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To assess the short term safety of the COVID-19 vaccines Comirnaty (Pfizer-BioNTech BNT162b2) and Vaxzevria (AstraZeneca ChAdOx1) in Australia.Prospective observational cohort study; online surveys by AusVaxSafety, a national active vaccine safety surveillance system, three and eight days after vaccination.People aged 16 years or more who received COVID-19 vaccines at sentinel vaccination hubs, general practices, or Aboriginal Community Controlled Health Organisation clinics, 22 February - 30 August 2021.Primary outcome: proportion of respondents who reported any adverse event following immunisation (AEFI) 0-3 days after vaccination.proportions of respondents who reported specific adverse events or medical review for AEFI within seven days of vaccination; impact on usual daily activities; recovery.4 851 480 people received COVID-19 vaccines at participating sentinel sites during the study period (25% of all COVID-19 vaccine doses administered in Australia to 30 August 2021). 3 035 983 people responded to both surveys (response rate, 62.6%); 35.9% of respondents reported one or more AEFI 0-3 days after Comirnaty dose 1, 54.7% after Comirnaty dose 2, 52.8% after Vaxzevria dose 1, and 22.0% after Vaxzevria dose 2. Local pain, fatigue, headache, and myalgia were the most frequently reported symptoms. After adjusting for demographic characteristics, vaccination site type, jurisdiction, and self-reported medical conditions, the odds of reporting any AEFI were higher for women than men (range of adjusted odd ratios [aORs], by vaccine and dose, 1.53-1.84), for people with a history of anaphylaxis (aOR range, 1.28-1.45), and for people reporting certain underlying conditions, including obesity (aOR range, 1.15-1.75), immunodeficiency (aOR range, 1.04-2.24), or chronic inflammatory disease (aOR range, 1.05-1.75). 0.9% of respondents sought medical advice in the three days following vaccination, most frequently after Comirnaty dose 2 (1.4%) and Vaxzevria dose 1 (1.2%).AusVaxSafety active surveillance affirms the short term safety profile of Comirnaty and Vaxzevria vaccines in a large population sample during the first six months of the Australian COVID-19 vaccination program.

BACKGROUND Population-level studies of severe pertussis extending beyond infancy are sparse, and none in the context of antenatal vaccination. We compared hospitalized pertussis cases from birth to 15 years of age before and after introduction of antenatal immunization. METHODS Active surveillance of laboratory-confirmed pertussis hospitalizations in a national network of pediatric hospitals in Australia January 2012 to June 2019. Impact of maternal vaccination was assessed by vaccine effectiveness (VE) in cases and test-negative controls with

Background Diphtheria is rare in Australia, but an increasing number of cases have been notified in recent years. Alongside notifications from 1999 to 2019, we analysed other relevant national data sources to evaluate trends over the past two decades. Methods Diphtheria notifications (National Notifiable Diseases Surveillance System [NNDSS]), hospitalisations (National Hospital Morbidity Database [NHMD]) and deaths (Australian Bureau of Statistics and the Australian Coordinating Registry) were separately analysed by site of infection, age group, sex, state/territory, Aboriginal and Torres Strait Islander status, and vaccination status. Results During the study period, eight (0.002 per 100,000 population per year) cases of respiratory diphtheria and 38 (0.008 per 100,000 population per year) cases of cutaneous diphtheria were recorded in the NNDSS, with 45/46 reported in the nine years since 2011. Corynebacterium diphtheriae accounted for 87% of notified cases, who had a median age of 31.5 years (respiratory diphtheria) and 52.5 years (cutaneous diphtheria); no respiratory diphtheria was notified in those under 15 years of age. A majority of the cutaneous diphtheria cases (27/38; 71%) were acquired overseas, as were 3/8 (38%) of the respiratory diphtheria cases. Rates of both presentation types were higher in Aboriginal and Torres Strait Islander people (respiratory: 0.007 per 100,000 population per year; cutaneous: 0.021 per 100,000 population per year) than were rates in the overall population. Queensland had the highest rate of notified respiratory cases (0.007 per 100,000 population per year), and the Northern Territory the highest rate of cutaneous notifications (0.043 per 100,000 population per year). There were 29 hospitalisations with a principal-diagnosis diphtheria code in the NHMD between 2002 and 2018, of which eight were designated as respiratory (0.002 per 100,000 population per year), eight as cutaneous (0.002 per 100,000 population per year), and 13 with an unknown site of infection. Among notified cases, two deaths were reported in unvaccinated people in Queensland. Conclusions Although diphtheria remains rare in Australia, 45 cases were notified in the years 2011–2019, compared with one case between 1999 and 2010. Robust surveillance remains important to detect all cases. High immunity will need to be maintained across all age groups to prevent outbreaks, and travel and adult booster doses should be encouraged.

Background Data sources, relevant to measles epidemiology from 2012 to 2019, were reviewed in the context of Australia’s certification, by the World Health Organization in 2014, of the elimination of measles. Methods Data on measles notifications, hospitalisations, and deaths were obtained from the National Notifiable Diseases Surveillance System, the National Hospital Morbidity Database, and the Australian Coordinating Registry. Data were analysed by age group, state/territory, Aboriginal and Torres Strait Islander status, genotype, place of acquisition, source of infection (importation status), and vaccination status. Results Between 2012 and 2019, there were 1,337 measles notifications (average annual notifications 0.7 per 100,000 population per year) and 425 hospitalisations with measles as principal diagnosis (0.3 per 100,000 population per year) were recorded. The highest annual notification rate was in 2014, when the rate in the Northern Territory was 21.4 per 100,000 population per year. Although notification and hospitalisation rates were highest in infants < 12 months (respectively 5.8 and 2.1 per 100,000 population per year), people aged 10 to 39 years (10–19y: 272 notifications; 20–29y: 347; 30–39y: 266) accounted for 66% of notified cases. Of cases with a known vaccination status, only 20/169 (11.8%) of those aged 1–9 years had received at least one dose of measles-containing vaccine, compared with 215/571 (37.7%) of those aged 10–39 years. Persons born before 1966 (at least 47 years of age during the study period) are likely to have immunity from wild-type measles infection and had the lowest notification rates in each year. Of notified cases, 98.1% were imported or import related, and of the 900 measles viruses genotyped, D8 and B3 accounted for 89.1%. Conclusion This review’s findings of low measles incidence, in the presence of robust surveillance and high two-dose measles vaccination coverage, provide evidence of continued elimination of endemic measles in Australia, with almost all cases imported or epidemiologically linked to an imported case. Most cases eligible for vaccination are unvaccinated, which should remain the primary focus for prevention. Potential waning immunity in older age groups requires monitoring. Continued high population immunity and high-quality public health response to cases will be needed to maintain Australia’s elimination status, particularly once international borders reopen.

Objectives To estimate SARS‐CoV‐2‐specific antibody seroprevalence after the first epidemic wave of coronavirus disease 2019 (COVID‐19) in Sydney. Setting, participants People of any age who had provided blood for testing at selected diagnostic pathology services (general pathology); pregnant women aged 20–39 years who had received routine antenatal screening; and Australian Red Cross Lifeblood plasmapheresis donors aged 20–69 years. Design Cross‐sectional study; testing of de‐identified residual blood specimens collected during 20 April – 2 June 2020. Main outcome measure Estimated proportions of people seropositive for anti‐SARS‐CoV‐2‐specific IgG, adjusted for test sensitivity and specificity. Results Thirty‐eight of 5339 specimens were IgG‐positive (general pathology, 19 of 3231; antenatal screening, 7 of 560; plasmapheresis donors, 12 of 1548); there were no clear patterns by age group, sex, or location of residence. Adjusted estimated seroprevalence among people who had had general pathology blood tests (all ages) was 0.15% (95% credible interval [CrI], 0.04–0.41%), and 0.29% (95% CrI, 0.04–0.75%) for plasmapheresis donors (20–69 years). Among 20–39‐year‐old people, the age group common to all three collection groups, adjusted estimated seroprevalence was 0.24% (95% CrI, 0.04–0.80%) for the general pathology group, 0.79% (95% CrI, 0.04–1.88%) for the antenatal screening group, and 0.69% (95% CrI, 0.04–1.59%) for plasmapheresis donors. Conclusions Estimated SARS‐CoV‐2 seroprevalence was below 1%, indicating that community transmission was low during the first COVID‐19 epidemic wave in Sydney. These findings suggest that early control of the spread of COVID‐19 was successful, but efforts to reduce further transmission remain important.

Summary Background School closures have occurred globally during the COVID-19 pandemic. However, empiric data on transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among children and in educational settings are scarce. In Australia, most schools have remained open during the first epidemic wave, albeit with reduced student physical attendance at the epidemic peak. We examined SARS-CoV-2 transmission among children and staff in schools and early childhood education and care (ECEC) settings in the Australian state of New South Wales (NSW). Methods Laboratory-confirmed paediatric (aged ≤18 years) and adult COVID-19 cases who attended a school or ECEC setting while considered infectious (defined as 24 h before symptom onset based on national guidelines during the study period) in NSW from Jan 25 to April 10, 2020, were investigated for onward transmission. All identified school and ECEC settings close contacts were required to home quarantine for 14 days, and were monitored and offered SARS-CoV-2 nucleic acid testing if symptomatic. Enhanced investigations in selected educational settings included nucleic acid testing and SARS-CoV-2 antibody testing in symptomatic and asymptomatic contacts. Secondary attack rates were calculated and compared with state-wide COVID-19 rates. Findings 15 schools and ten ECEC settings had children (n=12) or adults (n=15) attend while infectious, with 1448 contacts monitored. Of these, 633 (43·7%) of 1448 had nucleic acid testing, or antibody testing, or both, with 18 secondary cases identified (attack rate 1·2%). Five secondary cases (three children; two adults) were identified (attack rate 0·5%; 5/914) in three schools. No secondary transmission occurred in nine of ten ECEC settings among 497 contacts. However, one outbreak in an ECEC setting involved transmission to six adults and seven children (attack rate 35·1%; 13/37). Across all settings, five (28·0%) of 18 secondary infections were asymptomatic (three infants [all aged 1 year], one adolescent [age 15 years], and one adult). Interpretation SARS-CoV-2 transmission rates were low in NSW educational settings during the first COVID-19 epidemic wave, consistent with mild infrequent disease in the 1·8 million child population. With effective case-contact testing and epidemic management strategies and associated small numbers of attendances while infected, children and teachers did not contribute significantly to COVID-19 transmission via attendance in educational settings. These findings could be used to inform modelling and public health policy regarding school closures during the COVID-19 pandemic. Funding NSW Government Department of Health.

Aim: To identify barriers to influenza vaccination of children hospitalised for acute respiratory illness in Australia. Methods: A total of 595 parents of children hospitalised with acute respiratory illness across five tertiary hospitals in 2019 participated in an online survey. Multivariate logistic regression identified factors most strongly associated with influenza vaccination barriers. Results: Odds of influenza vaccination were lower with lack of health-care provider (HCP) recommendation (adjusted odds ratio (aOR) 0.18; 95% confidence interval (CI): 0.08–0.38); if parents had difficulties (aOR 0.19; 95% CI: 0.08–0.47) or were ‘neutral’ (aOR 0.23; 95% CI: 0.06–0.82) in remembering to make an appointment; and if parents had difficulties (aOR 0.21; 95% CI: 0.07–0.62) or were ‘neutral’ (aOR 0.24; 95% CI: 0.07–0.79) regarding getting an appointment for vaccination. Odds were also lower if parents did not believe (aOR 0.27; 95% CI: 0.08–0.90) or were ‘neutral’ (aOR 0.15; 95% CI: 0.04–0.49) regarding whether the people most important to them would have their child/ren vaccinated against influenza. Children had lower odds of vaccination if parents did not support (aOR 0.09; 95% CI: 0.01–0.82) or were ambivalent (aOR 0.09; 95% CI: 0.01–0.56) in their support for influenza vaccination. Finally, lack of history of influenza vaccination of child (aOR 0.38; 95% CI: 0.18–0.81) and respondent (aOR 0.25; 95% CI: 0.11–0.56) were associated with lack of receipt of influenza vaccine before admission for acute respiratory infection. Conclusions: Assisting parents in remembering and accessing influenza vaccination and encouraging health-care providers to recommend vaccination may increase uptake.

Background: This study evaluates trends in tetanus immunity and epidemiology over the last two decades in Australia, drawing on two national serological surveys and national tetanus morbidity data, to justify current Australian adult tetanus booster recommendations. Methods: We compare tetanus immunity level between two national serosurveys, and examine incidence trends using the most accurate estimation of the true number of cases by correcting for under-ascertainment. Results: Tetanus immunity in people aged Conclusion: Despite a positive decrease in tetanus incidence, there remains a significant burden in the elderly population of an entirely preventable disease. Supplying a funded booster dose of dTpa at 65 years would be, potentially, an effective strategy to prevent tetanus cases in Australia.

Background As of mid-2021, Australia’s only nationwide coronavirus disease 2019 (COVID-19) epidemic occurred in the first 6 months of the pandemic. Subsequently, there has been limited transmission in most states and territories. Understanding community spread during the first wave was hampered by initial limitations on testing and surveillance. To characterize the prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific antibody seroprevalence generated during this time, we undertook Australia’s largest national SARS-CoV-2 serosurvey. Methods Between June 19 and August 6, 2020, residual specimens were sampled from people undergoing general pathology testing (all ages), women attending antenatal screening (20–39 years), and blood donors (20–69 years) based on the Australian population’s age and geographic distributions. Specimens were tested by Wantai total SARS-CoV-2-antibody assay. Seroprevalence estimates adjusted for test performance were produced. The SARS-CoV-2 antibody-positive specimens were characterized with microneutralization assays. Results Of 11 317 specimens (5132 general pathology; 2972 antenatal; 3213 blood-donors), 71 were positive for SARS-CoV-2-specific antibodies. Seroprevalence estimates were 0.47% (95% credible interval [CrI], 0.04%–0.89%), 0.25% (CrI, 0.03%–0.54%), and 0.23% (CrI, 0.04%–0.54%), respectively. No seropositive specimens had neutralizing antibodies. Conclusions Australia’s seroprevalence was extremely low (

Introduction Significant recent changes in Australian pertussis immunisation policy include the progressive introduction of funded pertussis immunisation programs for pregnant women, from late 2014 to mid-2015 at jurisdictional level and then under the National Immunisation Program from July 2018, and reintroduction of the 18-month booster dose in 2016. This study analyses pertussis notification, hospitalisation, and mortality data from 2013 to 2018 in the context of trends since 1995. Methods This study used data from the National Notifiable Diseases Surveillance System, the National Hospital Morbidity Database, and the Australian Coordinating Registry, for descriptive analysis of pertussis notifications, hospitalisations and deaths in Australia by Aboriginal and Torres Strait Islander (Indigenous) status from 2013 to 2018, examining trends between 1995 and 2012 at both the national and jurisdictional level. Incidence rate ratios (IRR) were utilised to compare pertussis incidence in infants aged < 2 months and 6–11 months for each year from the 2015–2018 (post-maternal-vaccination) period against the 2010–2013 (pre-maternal-vaccination) period. Results and Discussion Annual national all-age incidence of pertussis notifications between 2013 and 2018 was 63.6 per 100,000 population, 40% less than between 2006 and 2012. Between 2016 and 2018, infants aged < 2 months had the lowest notification rates of age groups < 5 years old, with the highest notification rates in pre-adolescents aged 9–11 years. Compared with the baseline period (2010–2013), the IRR for infants aged < 2 months decreased in each year during the post-maternal-vaccination period from 0.4 (95% confidence interval [95% CI]: 0.3–0.5) in 2015 to 0.1 (95% CI: 0.1–0.2) in 2018. For infants aged 6–11 months, the IRR was 0.9 (95% CI: 0.8–1.0) in 2015, 1.1 (95% CI: 1.0–1.2) in 2016 and declined to 0.7 (95% CI: 0.6–0.8) in 2017 and 2018. Notification and hospitalisation rates in Indigenous children were 3–8 times as high as rates in non-Indigenous children across all age groups < 5 years old. Conclusion Pertussis remains the second most frequently notified vaccine preventable disease in Australia, after influenza, but dramatic decreases in incidence have been observed in infants too young to receive any doses of pertussis-containing vaccine.

Infants aged6 months are vulnerable to severe influenza disease and no vaccine is approved for use in this age group. We aimed to describe the epidemiology, risk factors associated with severe outcomes and management of influenza in Australian infants aged6 months.Incident cases aged6 months of laboratory-confirmed influenza were captured through two national active prospective sentinel hospital-based surveillance systems in Australia from 2011 to 2019, inclusive. Demographic and clinical features, disease risk factors and outcomes (intensive care unit (ICU) admission and length of stay) and oseltamivir use were analysed. The proportion of infant influenza hospitalisations and nosocomial cases among all hospitalisations were also reported.Of 680 hospitalised infants aged6 months, 57.9% were male and 14.5% were Indigenous Australian. Median age was 2.6 months, 19.2% were born premature and 19.0% had a comorbidity, excluding prematurity. Overall, 77.9% had influenza A. Nosocomial cases accounted for 7.8%. ICU admission occurred in 14.7% and oseltamivir was prescribed for 18.8%. Factors associated with ICU admission included age1 month (adjusted odds ratio (aOR) 3.95, 95% confidence interval (CI): 1.47-10.60), comorbidity (aOR 7.69, 95% CI: 4.04-14.64) and prematurity (aOR 2.60, 95% CI: 1.40-4.81). The proportion of infants with influenza among all infant hospitalisations ranged 1.0-2.6% in the 2019 influenza season.Infants aged6 months, and particularly neonates, experience serious disease from influenza. This data underpins the need for preventative strategies such as maternal immunisation and continued investigation into the possibility of safe and efficacious vaccination prior to 6 months of age.

Population-level studies of severe pertussis extending beyond infancy are sparse, and none in the context of antenatal vaccination. We compared hospitalized pertussis cases from birth to 15 years of age before and after introduction of antenatal immunization.Active surveillance of laboratory-confirmed pertussis hospitalizations in a national network of pediatric hospitals in Australia January 2012 to June 2019. Impact of maternal vaccination was assessed by vaccine effectiveness (VE) in cases and test-negative controls with2 months of age and by before-after comparison of age distribution of cases. Among cases eligible for one or more vaccine doses, we examined proportions age-appropriately immunized and with comorbidities by age group.Among 419 eligible cases, the proportion2 months of age significantly decreased from 33.1% in 2012 to 2014 compared with 19.6% in 2016 to 2019 when mothers of only 4 of 17 (23.5%) cases2 months of age had received antenatal vaccination. VE was estimated to be 84.3% (95% CI, 26.1-96.7). Across all years (2012-2019), of 55 cases 4-11 months of age, 21 (38%) had ≥2 vaccine doses, whereas among 155 cases ≥12 months of age, 122 (85.2%) had ≥3 vaccine doses. Prevalence of comorbidities (primarily cardiorespiratory) increased from 5 (2.1%)6 months of age to 36 (24.2%) ≥12 months of age (P0.001), with 6/16 (38%) cases ≥12 months of age who required intensive care having comorbidities.Below the age of 12 months, prevention of severe pertussis will be maximized by high maternal antenatal vaccine uptake and timeliness of infant vaccine doses. Despite full immunization, we found children ≥12 months of age accounted for 27% of hospitalizations15 years, with 24% having comorbities, suggesting new vaccine strategies, such as additional doses or more immunogenic vaccines, require evaluation.

Introduction The Paediatric Active Enhanced Disease Surveillance (PAEDS) network is an Australian hospital-based active surveillance system employing prospective case ascertainment for selected serious childhood conditions, particularly vaccine preventable diseases and potential adverse events following immunisation (AEFI). This report presents surveillance data for 2019. Methods Specialist nurses screened hospital admissions, emergency department records, laboratory and other data on a daily basis in seven paediatric tertiary referral hospitals across Australia, to identify children with the conditions under surveillance. Standardised protocols and case definitions were used across all sites. In 2019, the conditions under surveillance comprised: acute flaccid paralysis (AFP; a syndrome associated with poliovirus infection), acute childhood encephalitis (ACE), influenza, intussusception (IS; a potential AEFI with rotavirus vaccines), pertussis, varicella-zoster virus infection (varicella and herpes zoster), invasive meningococcal and invasive Group A streptococcus diseases and two new conditions, Kawasaki disease and gram-negative bloodstream infections. An additional social research component continued to evaluate parental attitudes to influenza vaccination. Results PAEDS captured 2,701 cases for 2019 across all conditions under surveillance. Key outcomes of PAEDS included: contribution to national AFP surveillance to reach the World Health Organization reporting targets for detection of poliomyelitis cases; demonstration of high influenza activity in 2019 and influenza-associated deaths in ACE cases; identification of key barriers to influenza vaccination of children hospitalised for acute respiratory illness; reporting of all IS cases associated with vaccine receipt to relevant state health department; and showing a further reduction nationally in varicella cases. Enhanced pertussis surveillance continued to capture controls to support vaccine efficacy estimation. Invasive meningococcal disease surveillance showed predominance of serotype B and a reduction in cases nationally. Surveillance for invasive group A streptococcus captured severe cases in children. Monitoring of Kawasaki disease incidence and gram-negative bloodstream infections commenced. Conclusions PAEDS continues to provide unique policy-relevant data on serious paediatric conditions using sentinel hospital-based enhanced surveillance. Keywords: paediatric, surveillance, child, hospital, vaccine preventable diseases, adverse event following immunisation, acute flaccid paralysis, encephalitis, influenza, intussusception, pertussis, varicella zoster virus, meningococcal, group A streptococcus, Kawasaki, bloodstream infections.

This report summarises Australian spontaneous surveillance data for adverse events following immunisation (AEFI) for 2019 reported to the Therapeutic Goods Administration (TGA) and describes reporting trends over the 20-year period from 1 January 2000 to 31 December 2019. There were 3,782 AEFI records for vaccines administered in 2019, an annual AEFI reporting rate of 14.9 per 100,000 population. There was an 11.8% decrease in the overall AEFI reporting rate in 2019 compared to 2018 (16.9 per 100,000 population). This decrease in the AEFI reporting rate in 2019 was mainly attributable to a decline in reported adverse events related to the human papillomavirus (HPV), dTpa, meningococcal ACWY and seasonal influenza vaccines. AEFI reporting rates for most individual vaccines in 2019 were similar to 2018. The most commonly-reported adverse events were injection site reaction (35.8%), rash (16.6%), pyrexia (15.3%), vomiting (8.1%), urticaria (5.8%), pain (5.8%) and headache (5.7%). There were five deaths reported to the TGA. In one report, the timing and clinical findings were consistent with a causal association with vaccination. In the remaining four reports, no clear causal relationship with vaccination was found.

Objectives To determine population-level immunity to mumps in Australia. Methods We tested randomly selected specimens from people aged 1-49 years using the Enzygnost anti-parotitis IgG enzyme immunoassay from an opportunistically collected serum bank in 2012-2013. Weighted estimates of the proportion seropositive and equivocal for mumps-specific IgG antibody were determined by age group and compared with two previous national serosurveys conducted in 2007-2008 and 1997-1998. Results Overall, 82.1% (95% CI 80.6-83.5%) of 2,729 specimens were positive or equivocal for mumps-specific IgG antibodies (71.1% positive [95% CI 69.4-72.9%]; 10.9% equivocal [95% CI 9.8-12.2%]). The proportion positive or equivocal was higher in 2012-2013 (82.1%) than in 2007-2008 (75.5%) and 1997-1998 (72.5%), but varied by age. The proportion positive or equivocal in 2012-2013 was above 80% for all age groups older than 1 year except for 30-34 year olds, corresponding to the 1978-1982 birth cohort previously identified as most likely to have missed out on a second MMR vaccine dose. Conclusion Seropositivity to mumps in 2012-2013 was well-maintained compared with previous serosurveys. Low mumps notifications over this period in Australia suggest an absence of community-based transmission of mumps infection in the general population, but recent outbreaks among Aboriginal adolescents and young adults in close-contact settings, despite high 2-dose MMR coverage, suggest that seroprotection may be insufficient in other similar settings in Australia.Seropositivity to mumps in 2012-2013 was well-maintained compared with previous serosurveys. Low mumps notifications over this period in Australia suggest an absence of community-based transmission of mumps infection in the general population, but recent outbreaks among Aboriginal adolescents and young adults in close-contact settings, despite high 2-dose MMR coverage, suggest that seroprotection may be insufficient in other similar settings in Australia.

Key Points Question Were the 2018 adjuvanted trivalent inactivated influenza vaccine (TIIV) and high-dose TIIV associated with adverse events in Australian individuals 65 years or older? Findings In this cohort study of active safety surveillance system data including 50 134 adults 65 years or older who responded to a short messaging service–based survey of self-reported adverse events following immunization, 94.4% of participants received an adjuvanted TIIV or high-dose TIIV. Individuals who received a high-dose TIIV reported higher rates of select adverse events, including fever and injection site reactions, but rates of seeking care were low and did not differ between enhanced vaccine groups. Meaning The findings of this postmarketing active sentinel surveillance system study consisting of self-reported adverse events following immunization suggest that these 2 new enhanced influenza vaccines were well tolerated among an older Australian population., This cohort study examines rates of adverse events following vaccinations among Australian adults 65 years or older who received influenza vaccines in 2018., Importance Every year, influenza vaccines are administered to millions of people worldwide to reduce morbidity and mortality from influenza. As new vaccine formulations are increasingly used, monitoring and comparing safety, in addition to vaccine effectiveness, in target populations are essential. Objective To assess the postmarketing safety profile of 2018 Southern Hemisphere influenza vaccines, particularly 2 new enhanced trivalent inactivated influenza vaccines: an adjuvanted trivalent inactivated influenza vaccine (aIIV3) and high-dose trivalent inactivated influenza vaccine (HD-IIV3), among Australian individuals 65 years or older. Design, Setting, and Participants This cohort study used solicited short message service–based self-reported survey data on adverse events occurring within 3 to 5 days after receipt of an influenza vaccination. Participants included individuals 65 years or older who received routinely recommended influenza vaccines at 1 of 265 sentinel immunization sites, including primary care, hospital, and community-based clinics, participating in Australia’s AusVaxSafety active vaccine safety surveillance system from April 1 to August 31, 2018. Data were analyzed from September 1, 2018, to June 30, 2019. Exposure Any licensed 2018 influenza vaccine administered in clinical practice. Main Outcomes and Measures Rates (overall, by brand, and by concomitant vaccine receipt) of adverse events, including medical attendance as a proxy for serious adverse events. Results Of 72 013 individuals 65 years or older who received an influenza vaccine in 2018, 50 134 individuals (69.6%) responded to the initial survey regarding adverse events experienced after vaccination (median [interquartile range] age, 71 [68-76] years; 27 056 [54.0%] women). Most individuals received an enhanced trivalent inactivated influenza vaccine, including 28 003 individuals (55.9%) who received aIIV3 and 19 306 individuals (38.5%) who received HD-IIV3; 2208 individuals (4.4%) received a quadrivalent inactivated influenza vaccine. Individuals who received HD-IIV3 reported significantly higher rates of any adverse event compared with individuals who received aIIV3 (1716 individuals [8.9%] vs 1796 individuals [6.4%]; P < .001) as well as specific adverse events, including fever (195 individuals [1.1%] vs 164 individuals [0.6%]; P

Background Four-component meningococcal B (4CMenB) vaccine is licensed in many countries but has had limited use in adolescents despite this age group being at increased risk of meningococcal disease. Objectives To assess the safety profile of two doses of 4CMenB in adolescents. Methods Cluster randomised controlled trial of senior school students in South Australia (SA) with participating schools randomised to intervention (4CMenB) or control. Vaccine safety was monitored using the South Australian Vaccine Safety Surveillance System (SAVSS), a spontaneous reporting system for adverse events following immunisation (AEFI) with enhanced follow-up of AEFI. Results 58,637 doses of 4CMenB vaccine were administered to 30,522 students (median age 16 years) during 2017–2018. Of 18,348 and 12,174 students vaccinated in 2017 and 2018, 97.3% and 84.3%, respectively, received both scheduled doses (N = 28,115). 193 AEFI in 187 students were reported with a reporting rate of 0.32% (95%CI: 0.28–0.39%). Seventy individuals sought medical review, including nine serious adverse events. 98% (166/169) of those who were contactable for AEFI follow-up (87.6% 169/193) reported resolution of the event. Most common AEFI were injection site reaction (126/193), headache (99/193) and nausea (61/193). AEFI were more frequently reported in females (aOR = 1.409 (95%CI: 1.002, 1.980)), schools with high level of educational advantage (adjusted Odds Ratio (aOR) = 1.515 (95%CI: 1.005, 2.284)), following first dose (aOR = 1.619 (95%CI: 1.168, 2.244)), and in 2017 (aOR = 1.437 (95%CI: 1.001, 2.064)). Reported AEFI declined with increasing age (aOR = 0.771 (95%CI: 0.673, 0.883)). Conclusion In this largest post-licensure use of 4CMenB in adolescents, the low AEFI reporting rate provides real-world evidence of 4CMenB safety in this age group. (ClinicalTrials.gov number: NCT03089086).

This report summarises Australian spontaneous surveillance data for adverse events following immunisation (AEFI) for 2018 reported to the Therapeutic Goods Administration and describes reporting trends over the 19-year period 1 January 2000 to 31 December 2018. There were 4221 AEFI records for vaccines administered in 2018, an annual AEFI reporting rate of 16.9 per 100,000 population. There was a 2.9% increase in the overall AEFI reporting rate in 2018 compared to 2017. This slight increase in reported adverse events in 2018 was likely due to new additions to the National Immunisation Program schedule, namely meningococcal ACWY vaccination for children aged 12 months, enhanced immunogenicity trivalent influenza vaccines for adults aged ≥65 years, and state- and territory-funded seasonal influenza vaccination programs for children aged 6 months to

Q fever (caused by Coxiella burnetii) is thought to have an almost world-wide distribution, but few countries have conducted national serosurveys. We measured Q fever seroprevalence using residual sera from diagnostic laboratories across Australia. Individuals aged 1–79 years in 2012–2013 were sampled to be proportional to the population distribution by region, distance from metropolitan areas and gender. A 1/50 serum dilution was tested for the Phase II IgG antibody against C. burnetii by indirect immunofluorescence. We calculated crude seroprevalence estimates by age group and gender, as well as age standardised national and metropolitan/non-metropolitan seroprevalence estimates. Of 2785 sera, 99 tested positive. Age standardised seroprevalence was 5.6% (95% confidence interval (CI 4.5%–6.8%), and similar in metropolitan (5.5%; 95% CI 4.1%–6.9%) and non-metropolitan regions (6.0%; 95%CI 4.0%–8.0%). More males were seropositive (6.9%; 95% CI 5.2%–8.6%) than females (4.2%; 95% CI 2.9%–5.5%) with peak seroprevalence at 50–59 years (9.2%; 95% CI 5.2%–13.3%). Q fever seroprevalence for Australia was higher than expected (especially in metropolitan regions) and higher than estimates from the Netherlands (2.4%; pre-outbreak) and US (3.1%), but lower than for Northern Ireland (12.8%). Robust country-specific seroprevalence estimates, with detailed exposure data, are required to better understand who is at risk and the need for preventive measures.

Background: School closures have occurred globally during the COVID-19 pandemic despite limited data on transmission among children and in educational setting

Infants are at the highest risk of severe complications - including death - as a result of pertussis infection. Controlling pertussis in this group has been challenging, particularly in those too young to be vaccinated. Following revised national recommendations in March 2015, the state of New South Wales, Australia, introduced a funded maternal vaccination campaign at 28 - 32 weeks of gestation using a 3-component tetanus-diphtheria-acellular pertussis vaccine (dTpa; Boostrix, GSK). This study aimed to assess the effectiveness of maternal vaccination and add to the growing body of evidence for this strategy.A 1:1 matched case-control study was conducted between 16 August 2015 and 17 August 2016. Cases were laboratory or doctor notified, laboratory confirmed (nucleic acid testing or culture) and aged6 months at onset. Each control infant was randomly selected from public hospital births in the same geographical area in the period up to 3 days before and after the case's birthdate. Odds ratios (OR) were calculated using conditional logistic regression. Vaccine effectiveness (VE) was calculated as 1 - OR.In total, 117 cases and 117 controls were recruited. The overall VE estimate was non-significantly protective for infants6 months old (VE 39%, 95% CI -12 to 66%). Higher VE was observed for infants3 months old (VE 69%, 95% CI 13-89%) and against hospitalisation (VE 94%, 95% CI 59-99%).Maternal pertussis vaccination with a 3-component acellular vaccine was found to be highly effective at preventing severe disease in infants, but was less effective at preventing disease which did not require hospitalisation. The overall VE reported in this study was lower than in prior studies and suggests that maternal vaccination, while an effective strategy at preventing severe pertussis, is less effective at protecting against infection or mild disease.

Background Australia is one of only a few countries with a long-standing and consistent serosurveillance program. We conducted a national serosurvey in 2012–2013 to estimate population seroprevalence of measles-specific IgG and the effective reproduction number, R, and compare the results with the three previous serosurveys (1996–1999, 2002 and 2007) to examine trends following a decade of sustained measles control. Methods 2729 residual sera from 1 to 49 year olds were tested using the Enzygnost anti-measles IgG enzyme immunoassay (EIA). All sera in the equivocal range by EIA on re-testing and a random sample of low positive and negative sera were later tested by a microneutralisation assay. R was calculated from weighted estimates of the proportion seronegative by age using a previously developed contact matrix. Results In the 2012–13 serosurvey, anti-measles IgG seropositivity for 1–49 year olds was 80.8% (95% CI: 79.4–82.3%) and 8.9% (95% CI: 7.8–10.0%) had equivocal antibody levels. The increasing proportion of seronegative and equivocal individuals in age groups 10–39 years continued a trend seen in previous serosurveys. There was also an increase in equivocal results among 2–4 and 5–9 year old children, >90% of whom were recently vaccinated. R increased from 0.57 in 1999 to above the epidemic threshold of 1 in 2012–13 (R = 1.7). All 20 EIA negative sera, 238/241 (98.8%) equivocal sera, and 89/92 (96.7%) low positive sera had a titre Conclusions A number of countries with sustained measles control have now demonstrated that measles-specific IgG antibodies decline with time since vaccination. As there is good epidemiologic evidence of population-level protection, the implications of declining measles-specific IgG antibody levels for maintaining measles elimination are unclear. Novel studies to determine correlates of protection against measles transmission and disease in the post-elimination era are needed to help answer this question.

In November 2014, New South Wales Health was notified of a cluster of respiratory illness in a veterinary school. Active case finding identified another case at a local equine stud. All cases had exposure to the equine fetal membranes of Mare A. This tissue subsequently tested positive for Chlamydia psittaci using quantitative real-time polymerase chain reaction. We conducted a cohort study of the university and stud farm staff to determine risk factors for disease. Nine people were exposed to the fetal membranes of Mare A. Of these, five cases of psittacosis were identified. Two required hospital admission. Contact with birds was not associated with illness (RR = 0.5, 95% CI = 0.09–2.73). People who had direct contact with the abnormal fetal membranes were more likely to develop disease (RR = 11.77, 95% CI = 1.02–∞). The emergence of an association between horse exposure and C. psittaci infection has important implications for the prevention and control of psittacosis. Article summary line: Investigation of an outbreak of psittacosis in a rural veterinary school demonstrates novel source of infection for psittacosis through exposure to abnormal equine fetal membranes.

SUMMARYDuring May 2015, an increase inSalmonellaAgona cases was reported from western Sydney, Australia. We examine the public health actions used to investigate and control this increase. A descriptive case-series investigation was conducted. Six outbreak cases were identified; all had consumed cooked tuna sushi rolls purchased within a western Sydney shopping complex. Onset of illness for outbreak cases occurred between 7 April and 24 May 2015.Salmonellawas isolated from food samples collected from the implicated premise and a prohibition order issued. No further cases were identified following this action. Whole genome sequence (WGS) analysis was performed on isolates recovered during this investigation, with additionalS.Agona isolates from sporadic-clinical cases and routine food sampling in New South Wales, January to July 2015. Clinical isolates of outbreak cases were indistinguishable from food isolates collected from the implicated sushi outlet. Five additional clinical isolates not originally considered to be linked to the outbreak were genomically similar to outbreak isolates, indicating the point-source contamination may have started before routine surveillance identified an increase. This investigation demonstrated the value of genomics-guided public health action, where near real-time WGS enhanced the resolution of the epidemiological investigation.

BACKGROUND: Rotavirus vaccine has been funded for infants under the Australian National Immunisation Program since 2007, with Rotarix vaccine used in New South Wales, Australia, from that time. In 2017, New South Wales experienced a large outbreak of rotavirus gastroenteritis. We examined epidemiology, genotypic profiles, and vaccine effectiveness (VE) among cases. METHODS: Laboratory-confirmed cases of rotavirus notified in New South Wales between January 1, 2010 and December 31, 2017 were analyzed. VE was estimated in children via a case-control analysis. Specimens from a sample of hospitalized case patients were genotyped and analyzed. RESULTS: In 2017, 2319 rotavirus cases were reported, representing a 3.1-fold increase on the 2016 notification rate. The highest rate was among children aged CONCLUSIONS: Rotarix is highly effective at preventing laboratory-confirmed rotavirus in Australia, especially in infants aged 6 to 11 months. Reduced VE in older age groups and over time suggests waning protection, possibly related to the absence of subclinical immune boosting from continuously circulating virus. G8 genotypes have not been common in Australia, and their emergence, along with equinelike G3P[8], may be related to vaccine-induced selective pressure; however, further strain-specific VE studies are needed.

There are limited long-term data on seroprevalence of neutralising antibody (nAb) to the three poliovirus serotypes following the switch from oral polio vaccine (OPV) to inactivated polio vaccine (IPV). In Australia, combination vaccines containing IPV replaced OPV in late 2005. Using serum and plasma specimens collected during 2012 and 2013, we compared prevalence of nAb to poliovirus type 1 (PV1), type 2 (PV2) and type 3 (PV3) in birth cohorts with differing IPV and OPV eligibility from an Australian population-based sample. In the total sample of 1673 persons aged 12 months to 99 years, 85% had nAb against PV1, 83% PV2 and 67% PV3. In the cohort 12 to18 years (eligible for 4 OPV doses, last dose 8-14 years prior), a significantly lower proportion had nAb than in the 7 to12 year cohort (eligible for 3 OPV doses and an IPV booster, last dose 3-8 years prior) for all poliovirus types: [PV1: 87.1% vs. 95.9% (P = 0.01), PV2: 80.4% vs. 92.9% (P = 0.003) and PV3: 38.1% vs. 84.0% (P 0.0001)]. These data suggest individual-level immunity may be better maintained when an OPV primary schedule is boosted by IPV, and support inclusion of an IPV booster in travel recommendations for young adults who previously received only OPV.

This report summarises Australian passive surveillance data for adverse events following immunisation (AEFI) for 2017 reported to the Therapeutic Goods Administration and describes reporting trends over the 18-year period 1 January 2000 to 31 December 2017. There were 3,878 AEFI records for vaccines administered in 2017; an annual AEFI reporting rate of 15.8 per 100,000 population. There was a 12% increase in the overall AEFI reporting rate in 2017 compared with 2016. This increase in reported adverse events in 2017 compared to the previous year was likely due to the introduction of the zoster vaccine (Zostavax®) provided free for people aged 70–79 years under the National Immunisation Program (NIP) and also the state- and territory-based meningococcal ACWY conjugate vaccination programs. AEFI reporting rates for most other individual vaccines in 2017 were similar to 2016. The most commonly reported reactions were injection site reaction (34%), pyrexia (17%), rash (15%), vomiting (8%) and pain (7%). The majority of AEFI reports (88%) described non-serious events. Two deaths were reported that were determined to have a causal relationship with vaccination; they occurred in immunocompromised people contraindicated to receive the vaccines.

Background Despite recommendations that older adults receive acellular pertussis vaccines, data on direct effectiveness in adults aged over 50 years are sparse. Methods A case-control study nested within an adult cohort. Cases were identified from linked pertussis notifications and each matched to 3 controls on age, sex, and cohort recruitment date. Cases and controls were invited to complete a questionnaire, with verification of vaccination status by their primary care provider. Vaccine effectiveness (VE) was estimated by conditional logistic regression, with adjustment for reported contact with children and area of residence. Results Of 1112 notified cases in the cohort, we had complete data for 333 cases and 506 controls. Among 172 PCR-diagnosed cases (mean age, 61 years), 11.2% versus 19.5% of controls had provider-verified pertussis vaccination, on average, 3.2 years earlier. Adjusted VE against PCR-diagnosed pertussis was 52% (95% CI, 15–73%), nonsignificantly higher if vaccinated within 2 years (63%; −5–87%). Adjusted VE was similar in adults born before 1950, presumed primed by natural infection (51%; −8–77%) versus those born 1950 or later who may have received whole-cell pertussis vaccine (53%; −11–80%) (P-heterogeneity = 0.9). Among 156 cases identified by single-point serology, adjusted VE was −55% (−177–13%). Conclusions We found modest protection against PCR-confirmed pertussis among older adults (mean age, 61 years; range, 46–81 years) within 5 years after acellular vaccine. The most likely explanation for the markedly divergent VE estimate from cases identified by single-titer serology is misclassification arising from limited diagnostic specificity in our setting.

The Paediatric Active Enhanced Disease Surveillance (PAEDS) network is a hospital-based active surveillance system employing prospective case ascertainment for selected serious childhood conditions, particularly vaccine preventable diseases and potential adverse events following immunisation (AEFI). PAEDS data is used to better understand these conditions, inform policy and practice under the National Immunisation Program, and enable rapid public health responses for certain conditions of public health importance. PAEDS enhances data available from other Australian surveillance systems by providing prospective, detailed clinical and laboratory information on children with selected conditions. This is the third annual PAEDS report, and presents surveillance data for 2016.Specialist nurses screened hospital admissions, emergency department records, laboratory and other data, on a daily basis in 5 paediatric tertiary referral hospitals in New South Wales, Victoria, South Australia, Western Australia and Queensland to identify children with the conditions under surveillance. Retrospective data on some conditions was also captured by an additional hospital in the Northern Territory. Standardised protocols and case definitions were used across all sites. Conditions under surveillance in 2016 included acute flaccid paralysis (AFP) (a syndrome associated with poliovirus infection), acute childhood encephalitis (ACE), influenza, intussusception (IS; a potential AEFI with rotavirus vaccines), pertussis, varicella-zoster virus infection (varicella and herpes zoster), invasive meningococcal and invasive Group A streptococcus diseases. Most protocols restrict eligibility to hospitalisations; Emergency Department (ED) only presentations are also included for some conditions.In 2016, there were 673 cases identified across all conditions under surveillance. Key outcomes of PAEDS included: contribution to national AFP surveillance to reach World Health Organization (WHO) reporting targets; identification of the leading infectious causes of acute encephalitis which included human parechovirus, influenza, enteroviruses, Mycoplasma pneumoniae, and bacterial meningo-encephalitis; demonstration of high influenza activity with vaccine effectiveness (VE) analysis demonstrating some protection offered through vaccination. All IS cases associated with vaccine receipt were reported to the relevant state health department. Varicella and herpes zoster case numbers increased from previous years associated with suboptimal vaccination in up to 40% of cases identified. Pertussis surveillance continued in 2016 with the addition of test negative controls captured for estimating vaccine effectiveness. Surveillance for invasive meningococcal disease showed predominance for serotype B in absence of immunisation, and new invasive group A streptococcus surveillance captured severe disease in children.PAEDS continues to provide unique policy-relevant data on serious paediatric conditions using hospital-based sentinel surveillance.

This chapter discusses the characteristics and limitations of diagnostic tests for Bordetella pertussis infection, including bacterial culture, polymerase chain reaction, and serology. It then discusses surveillance for pertussis at the population level in high- and low-income settings, outlining the interplay of clinical, laboratory, and surveillance criteria in the identification and reporting of pertussis cases. The characteristics of pertussis surveillance systems are related to both detection and reporting of pertussis and can change, even within countries, if changes in diagnostic practice occur, making comparisons over time problematic. These considerations have significant implications for optimal surveillance of pertussis in different settings and assessment of resurgence, as also discussed in Chapter 4 on pertussis epidemiology.

Changes in circulating Bordetella pertussis genotypes, including a novel pertussis toxin promoter ptxP3 allele and absence of pertactin (Prn) antigen, have been reported from several countries but limited data on relative severity are available. We compared markers of disease severity in children with B. pertussis infection due to strains of differing genotype.Culture confirmed cases presenting to tertiary paediatric hospitals in three Australian states between 2008 and 2012 were classified as severe if they required a hospital stay greater than seven days, were admitted to intensive care, or if death occurred. Associations between age, vaccination, genotype and severity were assessed.Of 199 pertussis cases, 81 (41%) were3 months, including 32/39 (82%) of severe cases. The proportion of isolates from these cases that were Prn deficient increased markedly between 2008 and 2012. Of B. pertussis isolates, the proportion considered severe was similar for Prn positive (27/128, 21%) and Prn deficient (12/71, 17%) cases but only 1/22 (4.5%) of non ptxP3 cases were severe versus 38/177 (21.4%) ptxP3 positive. Adjusting for ptxP type, vaccination status and age, disease severity was not significantly associated with Prn status (RRA: 0.95, [0.57-1.56]; p = 0.83).In children, we found no relationship between Prn status and markers of severe pertussis. An increased proportion of severe disease in isolates with the ptxP3 allele was observed.

Background: This study assessed the impact of the staged introduction of universal infant and adolescent catch-up hepatitis B vaccination programs on the prevalence of immunity and past hepatitis B virus (HBV) infection in targeted cohorts over almost a decade in Australia. Methods: We compared the prevalence of immunity in relevant cohorts of children and adolescents in repeated national serological surveys conducted in 1998-99, 2002 and 2007. Residual sera (n =2210) collected opportunistically from Australian laboratories in 2007 were tested for antibody to hepatitis B surface antigen (anti-HBs) indicating vaccine-induced immunity; sera from individuals aged 12-29 years with anti-HBs detected (n =386) were then tested for hepatitis B core antibody (anti-HBc) to identify past hepatitis B infection. Results: In 2007, compared with the baseline period of 1998-99, anti-HBs prevalence had increased significantly in all age groups below 24 years, by more than double in target children. Prevalence of anti-HBc was zero in the 12-14 years and reduced by 71% in those aged 15-19 years. The hepatitis B vaccination protected a significant number of targeted adolescents with a modest vaccine uptake (57% to 60% nationally). Conclusion: In a setting without incentives or school entry requirements, adolescent vaccination coverage was significantly higher when delivered by school-based rather than GP-based mechanisms. A cohort of children was growing up in Australia with a high prevalence of vaccineinduced immunity against hepatitis B, providing the best opportunity for controlling HBV infection in Australia.

The Paediatric Active Enhanced Disease Surveillance (PAEDS) network is a hospital-based active surveillance system employing prospective case ascertainment for selected serious childhood conditions, particularly vaccine preventable diseases and potential adverse events following immunisation (AEFI). PAEDS data is used to better understand these conditions, inform policy and practice under the National Immunisation Program, and enable rapid public health responses for certain conditions of public health importance. PAEDS enhances data available from other Australian surveillance systems by providing prospective, detailed clinical and laboratory information on children with selected conditions. This is the second of the planned annual PAEDS reporting series, and presents surveillance data for 2015.Specialist surveillance nurses screened hospital admissions, emergency department records, laboratory and other data, on a daily basis in 5 paediatric tertiary referral hospitals in New South Wales, Victoria, South Australia, Western Australia and Queensland to identify children with the selected conditions. Standardised protocols and case definitions were used across all sites. Conditions under surveillance in 2015 included acute flaccid paralysis (a syndrome associated with poliovirus infection), acute childhood encephalitis (ACE), influenza, intussusception (IS; a potential AEFI with rotavirus vaccines), pertussis and varicella-zoster virus infection (varicella and herpes zoster). Most protocols restrict eligibility to hospitalisations, ED only presentations are also included for some conditions.: In 2015, there were 674 cases identified across all conditions under surveillance. Key outcomes of PAEDS included: contribution to national AFP surveillance to reach WHO reporting targets; identification of signals for Mycoplasma pneumoniae and parechovirus-related outbreaks (ACE surveillance); and demonstration of high influenza activity with vaccine effectiveness (VE) analysis supportive of vaccination. Surveillance for IS remains ongoing with any identified AEFIs reported to the relevant State Health Department; varicella and herpes zoster case numbers decreased slightly from previous years in older children not eligible for catch-up. Pertussis case numbers increased in early 2015 and analysis of cases in children aged1 year demonstrated the importance of timely childhood and maternal immunisation.PAEDS continues to provide unique policy-relevant data on serious paediatric conditions using hospital-based sentinel surveillance.

Background This national, sentinel prospective study aimed to identify children with severe hospitalized varicella, despite availability of universal 1-dose vaccination since 2005, and determine associations between virus genotypes and disease severity. Methods Children with varicella or zoster from 5 Paediatric Active Enhanced Disease Surveillance hospitals were enrolled. Lesions were swabbed for genotyping. Associations with disease severity were analyzed using multiple regression. Results From 2007 to 2015, 327 children with confirmed varicella (n = 238) or zoster (n = 89) were enrolled. Two hundred three (62%) were immunocompetent children; including 5 of 8 children who required intensive care unit management. Eighteen percent (36 of 203) of immunocompetent children had been previously vaccinated. Vaccinated children aged >18 months were less likely to have severe disease (9%; 5 of 56) than unvaccinated children (21%; 21 of 100; P = .05). Three of 126 children who had virus genotyping (2 immunocompromised) had varicella (n = 2) or zoster (n = 2) due to the Oka/vaccine strain. European origin clades predominated and were independently associated with more severe disease (odds ratio = 3.2; 95% confidence interval, 1.1- 9.5; P = .04). Conclusions Severe hospitalized varicella still occurs with a 1-dose varicella program, although predominantly in unvaccinated children. Most 1-dose vaccine recipients were protected against severe disease. Viral genotyping in complex hospitalized cases is important to assist in monitoring disease due to Oka-vaccine strain.

Summary Objectives To examine the impact of Australia's single dose infant varicella vaccination program, we assessed single dose varicella vaccine effectiveness (VE) in preventing hospitalised disease using two methods. Methods Clinically confirmed varicella cases from the Paediatric Active Enhanced Disease Surveillance (PAEDS) sentinel network were age-matched to 20 controls obtained from the Australian Immunisation Register. Conditional logistic regression models were used to estimate VE and compared with estimates obtained using our second approach. Results There were 78 hospitalised varicella cases during the post vaccine introduction period from January 2008 to December 2015, who were eligible for funded varicella vaccination. Median age at onset was 4.5 years and more than half (59%) were vaccinated. The majority of children received one vaccine brand (Varilrix, GSK). The estimated case-control VE for one dose of vaccine against hospitalised varicella was 64.7% (95% CI: 43.3–78.0%); estimates using the screening method were not significantly different. Exclusion of children who were immunocompromised did not significantly alter VE estimates. Conclusions Although Australia's program has impacted on the burden of varicella disease, single dose VE against varicella hospitalisation is only moderate. Greater reductions in varicella disease could potentially be achieved by incorporation of a second vaccine dose into the program to minimise breakthrough disease and interrupt virus circulation.

Background Unique among high-income countries, Australia has used a 3 + 0 schedule (3 primary doses, no booster) for infant pneumococcal conjugate vaccine (PCV) since January 2005, initially 7 valent (PCV7) then 13 valent (PCV13) from July 2011. We measured vaccine effectiveness (VE) of both PCVs against invasive pneumococcal disease (IPD) using 2 methods. Methods Cases were IPD notifications to the national surveillance system of children eligible for respective PCVs. For case-control method, up to 10 age-matched controls were derived from the Australian Childhood Immunisation Register. For indirect cohort method, controls were IPD cases due to serotypes not in PCVs. VE was calculated as (1 - odds ratio [OR]) × 100 by logistic regression. VE waning was estimated as odds of vaccine type (VT) IPD in consecutive 12-month periods post-dose 3. Results Between 2005 and 2014, there were 1209 and 308 IPD cases in PCV7-eligible and PCV13-eligible cohorts, respectively. Both methods gave comparable VE estimates. In infants, VE for 3 doses against VT IPD was 92.9% (95% confidence interval [CI], 27.7% to 99.3%) for PCV7 and 86.5% (95% CI, 11.7% to 97.9%) for PCV13. From 12 months post-dose 3, the odds of VT IPD by 24-36 months increased significantly for PCV7 (5.6, 95% CI, 1.2-25.4) and PCV13 (5.9, 95% CI, 1.0-35.2). Conclusions For both PCVs in a 3 + 0 schedule, despite similar VE, progressive increase in breakthrough cases only occurred post-PCV13. This supports the importance of a booster dose of PCV13 in the second year of life to maintain protection.

INTRODUCTION Australia's novel, active surveillance system, AusVaxSafety, monitors the post-market safety of vaccines in near real time. We analysed cumulative surveillance data for children aged 6 months to 4 years who received seasonal influenza vaccine in 2015 and/or 2016 to determine: adverse event following immunisation (AEFI) rates by vaccine brand, age and concomitant vaccine administration. METHODS Parent/carer reports of AEFI occurring within 3 days of their child receiving an influenza vaccine in sentinel immunisation clinics were solicited by Short Message Service (SMS) and/or email-based survey. Retrospective data from 2 years were combined to examine specific AEFI rates, particularly fever and medical attendance as a proxy for serious adverse events (SAE), with and without concomitant vaccine administration. As trivalent influenza vaccines (TIV) were funded in Australia's National Immunisation Program (NIP) in 2015 and quadrivalent (QIV) in 2016, respectively, we compared their safety profiles. RESULTS 7402 children were included. Data were reported weekly through each vaccination season; no safety signals or excess of adverse events were detected. More children who received a concomitant vaccine had fever (7.5% versus 2.8%; p

The Paediatric Active Enhanced Disease Surveillance (PAEDS) network is a hospital-based active surveillance system employing prospective case ascertainment of selected uncommon vaccine preventable diseases and potential adverse events following immunisation (AEFI). PAEDS enhances other Australian surveillance systems by providing prospective detailed clinical and laboratory data for the same child.Specialist surveillance nurses screen hospital admissions, emergency department records, laboratory and other data, to prospectively identify hospitalised children aged under 15 years in 5 paediatric tertiary referral hospitals in New South Wales, Victoria, South Australia, Western Australia and Queensland. Standardised protocols and case definitions are used across all sites. Conditions under surveillance include vaccine preventable diseases: acute flaccid paralysis, varicella, pandemic and seasonal influenza and pertussis, and potential AEFIs: febrile seizures and intussusception. PAEDS also conducts surveillance for acute childhood encephalitis.Since August 2007, PAEDS has recruited a total of 6,227 hospitalised cases in total, for all conditions. From January to December 2014, there were 1,220 cases recruited across all conditions. Key outcomes include: enhanced acute flaccid paralysis surveillance to reach World Health Organization targets; supporting varicella and influenza vaccination in children; confirmation of a known low risk of febrile seizures following the 1st dose of measles-mumps-rubella vaccine but no increased risk of febrile seizures after measles-mumps-rubella-varicella vaccine, and a slightly increased risk of developing intussusception 1-7 days after rotavirus vaccination in infants aged less than 3 months. Acute childhood encephalitis data facilitated rapid investigation and response to the enterovirus 71 outbreak in 2013-2014.PAEDS provides unique policy-relevant data. This is the first of planned PAEDS annual reports to Communicable Diseases Intelligence.

This report summarises Australian passive surveillance data for adverse events following immunisation (AEFI) for 2014 reported to the Therapeutic Goods Administration for 2014 and describes reporting trends over the 15-year period 1 January 2000 to 31 December 2014. There were 3,087 AEFI records for vaccines administered in 2014; an annual AEFI reporting rate of 13.2 per 100,000 population. There was a decline of 5% in the overall AEFI reporting rate in 2014 compared with 2013. This decline in reported adverse events in 2014 compared with the previous year was mainly attributable to fewer reports following the human papillomavirus (HPV) vaccine as it was the 2nd year of the extension of the National HPV Vaccination Program to males. AEFI reporting rates for most vaccines were lower in 2014 compared with 2013. The most commonly reported reactions were injection site reaction (27%), pyrexia (18%), rash (16%), vomiting (9%), headache (7%), and syncope (5%). The majority of AEFI reports described non-serious events while 7% (n=211) were classified as serious. There were 5 deaths reported with no clear causal relationship with vaccination found.

Background Australia instituted funded female human papillomavirus (HPV) immunization in 2007, followed by a targeted male vaccination program in 2013. To date, Australia is one of only several countries with a funded male HPV immunization program. In 2012-2013, we conducted a survey of HPV seroprevalence in males to assess whether or not a herd impact of female vaccination could be observed. Methods We conducted a cross-sectional study of de-identified residual diagnostic test serum samples from males aged 15-39 years from laboratories in 3 Australian states and calculated the proportion seropositive to HPV types 6, 11, 16, and 18. We compared type-specific results by age group against those from a baseline 2005 Australian HPV serosurvey. Results There were decreases in proportion seropositive for every HPV type across all age groups, many statistically significant. The largest decrease was observed for HPV-11, with decreases of 8- and 9-fold for ages 20-29 and 30-39 years, respectively. Despite substantial reductions in seroprevalence, at least 9% of males were seropositive for at least 1 of the 4 HPV types. Conclusions This is the first serosurvey confirming broad population-level impact in males from female HPV vaccination. Our research may assist policy makers considering implementing HPV vaccination programs.

BACKGROUND: Although recommended for almost a decade, evidence for field effectiveness of vaccinating close adult contacts of newborn infants against pertussis (“cocooning”) is lacking. We evaluated the impact of a government-funded cocoon program during a pertussis epidemic in New South Wales, Australia. METHODS: We matched all New South Wales laboratory-confirmed pertussis cases aged RESULTS: Case households had fewer immunized mothers (22% vs 32%) or fathers (20% vs 31%) but were more likely to include additional and older children. After adjustment, when both parents met our definition of immunized, risk of pertussis at CONCLUSIONS: Timely parental pertussis boosters provided significant protection. Evidence of protection from maternal vaccination prepregnancy is biologically plausible, and more precise data on the magnitude and duration of this is important for future policy recommendations.

Surveillance for intussusception (IS) has been recommended in countries using rotavirus vaccine, but can be resource intensive. There is little data about the relative severity of rotavirus vaccine-associated IS compared with other IS cases. We collected detailed clinical data on all cases to evaluate the validity of ICD coding for IS in routinely collected data and case severity.Hospitalizations and emergency department presentations coded as IS in infants aged12 months from July 1, 2007, to June 30, 2010, were classified using Brighton criteria by case note review. We used self-controlled case series analysis to estimate IS risk after vaccination for all and only Brighton level 1 cases.Of 179 unique episodes coded as IS, 110 (61%) met Brighton level 1 criteria; self-controlled case series analysis found a relative incidence of IS in days 1-7 after the first dose of RV1 of 11.1 (95% confidence interval: 2.6-48.0). When all coded episodes of IS were included, relative incidence was 4.0 (95% confidence interval: 1.3-12.7). The proportion of Brighton 1 cases requiring surgery was 39% for those within 21 days of vaccine receipt and 34% for others (P = 0.67).Using ICD-coded cases without individual confirmation yielded a lower point estimate of risk for IS post rotavirus vaccination; however, the risk remained statistically compatible with that for chart confirmed cases only. Analysis using healthcare databases to evaluate risk of IS if conducted without case confirmation may be insufficient to confirm a low-level risk. IS episodes after vaccination were not more severe.

Introduction Post-partum vaccination of new mothers is currently recommended in Australia to reduce pertussis infection in infants. Internationally, vaccination recommendations now include pregnant women in some countries. Understanding the awareness of pertussis vaccination recommendations among pregnant women, and their willingness to have the vaccine while pregnant is important for informing vaccine program implementation. Objective To determine awareness and intentions toward current recommendations for post-partum pertussis vaccination among Australian pregnant women, and their willingness to accept pertussis vaccine during pregnancy, should it be recommended in Australia in the future. Design Quantitative self-administered survey, using a non-random stratified sampling plan based on representative proportions by age, parity and region of residence. Participants and setting Pregnant women receiving antenatal care through three large, demographically diverse referral hospitals in metropolitan, urban and rural New South Wales, Australia. Results The response rate was 815/939 (87%). Most women (80%) reported willingness to have the pertussis vaccine during pregnancy, should it be recommended. Thirty four per cent of women intended to receive a pertussis vaccine post-partum, 17% had received it previously, while 45% had never heard of pertussis vaccine, had not thought about it, or were undecided about having it. Compared with those who had not received a recommendation to have the vaccine post-partum, women who had received a recommendation were 7 times more likely (95% CI 4–14) to report intention to have the vaccine. Conclusions Health care provider recommendation is paramount to raising awareness of pertussis vaccination recommendations among pregnant women. Women's willingness to have the vaccine while pregnant is encouraging, and indicates the potential for high pertussis vaccine coverage among pregnant women, should it be recommended in Australia.

Background In November 2005, Australia introduced a publicly funded single dose of varicella vaccine for children aged 18-months. We describe the impact of this program on varicella hospitalisations in Queensland and provide the first assessment of single-dose varicella vaccine effectiveness in Australia since the program commenced. Methods Age-standardised varicella hospitalisation rates were calculated for 2000–2014 and pre- and post-public funding period rates compared. Case-control studies were conducted to investigate the association between vaccine receipt and both varicella hospitalisations and uncomplicated varicella emergency department presentations. Cases were matched to controls from a population-based register by date of birth and state of residence. Vaccine effectiveness was calculated as (1 – odds ratio) × 100%. Results Compared to the pre-funded period (2000–2003), age-standardised varicella hospitalisation rates declined by more than 70% in 2011–2014 with varicella principal diagnosis rates declining from 5.7 to 1.6 per 100,000 population per year. Varicella vaccine effectiveness at preventing hospitalisation with a principal diagnosis of varicella among children aged 19-months to 6-years was 81.9% (95% confidence interval: 61.8–91.4%), while for emergency department presentations among children aged 19-months to 8-years it was 57.9% (95% confidence interval: 48.5–65.5%). Conclusions In Australia, the single-dose varicella vaccination program has substantially reduced varicella morbidity. The single-dose varicella vaccine schedule is moderately-to-highly effective against hospitalisation, but appears less effective against emergency department presentations.

BACKGROUND There is limited information on the incidence, morbidity and risk factors for pertussis in adults, particularly those aged over 65 years. METHODS Population-based prospective cohort study of 263094 adults aged over 45 years (mean 62.8 years) recruited in the Australian state of New South Wales (the 45 and Up Study) between 2006 and 2008, and followed by record-linkage to laboratory-confirmed pertussis notifications, hospitalizations, and death records. The incidence of pertussis notifications and hospitalizations and relative risk (RR) of pertussis according to various participant characteristics was estimated using proportional hazards models. RESULTS Over a total follow-up of 217524 person-years, 205 adults had a pertussis notification and 12 were hospitalized; the incidence rate was 94 (95% confidence interval [CI], 82-108) and 5.5 (95% CI, 3.1-9.7) per 100000 person-years, respectively. The incidence of a pertussis notification did not differ by age but hospitalization rates progressively increased (2.2, 8.5, and 13.5 per 100000 person-years in age groups 45-64, 65-74, and 75+ years, respectively; P(trend) = .01). After adjusting for age, sex, and other factors, adults with a high body mass index (BMI; RR=1.52; 95% CI, 1.06-2.19 for BMI 30+kg/m(2) vs BMI

This study evaluates the evidence for elimination of rubella and congenital rubella syndrome (CRS) in Australia, drawing on three national serosurveys conducted between 1996 and 2007 and supported by statutory notification and vaccine coverage data. Anti-rubella IgG seropositivity was defined as ≥ 10 IU/ml by EIA. Between 1998 and 2007, rubella notifications fell >100-fold, to an average of 2 cases per million and there were five confirmed cases of CRS, two of which were locally acquired in 2003. Weighted overall seropositivity remained constant among 1-49 year-olds (89.6% in 1999; 88.1% in 2007). Between 2002 and 2009, 95% of children received at least one dose of the measles-mumps-rubella (MMR) vaccine. All three serosurveys provided estimates for R less than 0.5, well below the epidemic threshold of 1. All available data are supportive of Australia being considered for elimination status. Further reductions in incidence of CRS will require continued attention to vaccine coverage in overseas-born women, as well as the maintenance of current high coverage level of two-dose MMR vaccination.

ObjectiveTo actively solicit adverse events experienced in the days following immunisation with quadrivalent inactivated influenza vaccine using Australia’s near real-time, participant-based vaccine safety surveillance system, AusVaxSafety.Design and settingObservational cohort study conducted in 194 sentinel surveillance immunisation sites (primary care, hospital and community-based clinics) across Australia.ParticipantsIndividuals aged ≥6 months who received a routine seasonal influenza vaccine at a participating site (n=102 911) and responded to a survey (via short message service or email) sent 3 days after vaccination about adverse events experienced (n=73 892; 71.8%).Main outcome measureNear real-time and cumulative participant-reported rates of any adverse event, fever or medical attendance experienced within 3 days after vaccination overall, by brand, age, pregnancy status and concomitant vaccine receipt.ResultsParticipant median age was 57 years (range: 6 months to 102 years); 58.1% (n=42 869) were female and 2.7% (n=2018) were pregnant. Near real-time fast initial response cumulative summation and Bayesian analyses of weekly event rates did not demonstrate a safety signal. Children aged 6 months to 4 years had higher event rates (522/6180; 8.4%) compared with older ages; participants aged ≥65 years reported fewer events (1695/28 154; 6.0%). There were no clinically significant differences in safety between brands, by age group or overall. Cumulative data analysis demonstrated that concomitant vaccination was associated with increased rates of fever (2.1% vs 0.8%) and medical attendance (0.8% vs 0.4%), although all rates were low and did not exceed expected levels.ConclusionsNovel, postmarketing AusVaxSafety surveillance demonstrated comparable and expected safety outcomes for the 2017 quadrivalent inactivated influenza vaccine brands used in Australia. These near real-time, participant-reported data are expected to encourage confidence in vaccine safety and promote uptake.

SUMMARYComparing pertussis epidemiology over time and between countries is confounded by differences in diagnostic and notification practices. Standardized serological methods applied to population-based samples enhance comparability. Population prevalence of different levels of pertussis toxin IgG (PT IgG) antibody, measured by standardized methods, were compared by age group and region of Australia between 1997/1998 and 2002. The proportion of 5- to 9-year-olds with presumptive recent pertussis infection (based on IgG levels ⩾62·5 ELISA units/ml) significantly decreased in 2002, consistent with notification data for the same period and improved uptake of booster vaccines following the schedule change from whole-cell to acellular vaccine. In contrast, recent presumptive infection significantly increased in adults aged 35–49 years. Population-based serosurveillance using standardized PT IgG antibody assays has the potential to aid interpretation of trends in pertussis incidence in relation to vaccine programmes and between countries.

Objectives: To describe the epidemiology of mumps and examine potential factors underlying the recent increase in the incidence of mumps in Australia. Design, setting and participants: Analytical descriptive study, for all Australian states and territories, of mumps notifications (1994-2007); hospitalisations for mumps (1994-2005); and mumps seroprevalence in a nationally representative sample of 2787 subjects (1997). Main outcome measures: Incidence of notifications and hospitalisations for mumps; seropositivity by birth cohort. Results: Notified mumps cases increased from 60 in 2002 to 231 in 2005 and 512 in 2007. Between 1994 and 2005, there were 605 hospitalisations for mumps. Mumps seropositivity in all states and territories in 1997 was high (range, 87.1%-94.3%). The predominant age group affected by mumps shifted to adults over time: between 2005 and 2007, 41% of cases occurred among people aged 20-29 years. Cases were concentrated among the birth cohort of 1978 to 1982, who had higher rates of notifications and hospitalisations for mumps and a lower seropositivity rate (92% [95% Cl, 89%-94%]) than other birth cohorts. Conclusions: The birth cohort of 1978 to 1982 was too old to reliably receive a second dose of measles-mumps-rubella (MMR) vaccine in the 1998 Australian Measles Control Campaign and too young to have had mumps infection. Renewed efforts to maximise two-dose MMR coverage are important for prevention of mumps and measles in young adults.