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Objective: To examine how routine hepatitis B surface antigen (HBsAg) testing of antenatal women (as identified on the NT Midwifes Data Collection System) can be used to track the impact of hepatitis B (HBV) vaccination on the prevalence of chronic HBV infection in the Northern Territory (NT). Methods: Women who gave birth between 01 July 2002 and 30 June 2004 were identified from the NT Midwives Data Collection System (MDCS). For each woman, the unique hospital record number (HRN) was linked to the information system of the NT Government pathology service to obtain the results of serological tests for hepatitis B. The prevalence of HBsAg was calculated by age, Indigenous status, and maternal country of birth. Results: During the study period, 1061 records of women from the NT MDCS could be linked to HBsAg results. Overall, 33 (3.1%) were positive for HBsAg, of whom 29 were recorded as Indigenous and the remaining four were born outside Australia. Conclusions: Linking data from the NT MDCS and HBsAg results from government pathology service is a feasible means to monitor the impact of HBV vaccination policy. Implications: Routine inclusion of HBsAg results in all state and territory midwives data collections should be pursued.

Pertussis is a particular concern in infants under 6 months of age. They have the highest rates and severity of disease resulting in hospitalisation or death but are too young to be protected by current vaccination schedules. We outline the current epidemiology of pertussis in Australia and four potential strategies to prevent pertussis in the very young. First, universal adult and or adolescent vaccination; second, indirect protection of infants by immunisation of parents and possibly others in close contact with the newborn, such as grandparents and health-care workers; third, newborn and early infant vaccination (from birth to 1 month of age) and fourth maternal vaccination.

We compared the results of two national serosurveys in Australia to evaluate the impact of universal infant vaccination and school-based programs for adolescents. Immunity improved significantly overall, especially in 1-year-olds (40.0% versus 86%; p0.0001); in adolescents it was significantly higher in regions with established school-based programs (56.6% versus 38.8%; p=0.0008). 6.1% of 1-59-year-olds were positive for HBcAb and 0.7% for HBsAg. We have demonstrated successful implementation of universal infant hepatitis B vaccination in Australia and that school-based programs for adolescents are effective. This experience should be applicable to low prevalence countries in northern Europe which have not implemented universal hepatitis B immunisation.

Objective: Vaccine effectiveness analysis serves as a critical evaluation for immunization programmes and vaccination coverage. It also contributes to maintaining public confidence with the vaccine providers. This study estimated measles vaccine effectiveness at the population level using Australian national notifications data between 2006 and 2012. Methods: Notification data were obtained from the National Notifiable Diseases Surveillance System. Vaccination status was classified according to whether a case had received zero, one or two doses of measles-containing vaccine. Cases aged less than 1 year and those with unknown vaccination status were excluded. All children with disease onset between 1 January 2006 and 31 December 2012 who were born after 1996 were included. Cases were matched to controls extracted from the Australian Childhood Immunisation Register according to date of birth and jurisdiction of residence. Vaccine effectiveness was estimated by conditional logistic regression. Sensitivity analyses were conducted to test data robustness. Results: Vaccine effectiveness was estimated at 96.7% (95% confidence interval [CI]: 94.5–98.0%) for one dose and 99.7% (95% CI: 99.2–99.9%) for two doses of measles vaccine. For at least one dose, effectiveness was estimated at 98.7% (95% CI: 97.9–99.2%). Sensitivity analyses did not significantly alter the base estimates. Discussion: Vaccine effectiveness estimates suggested that the measles vaccine was protective at the population level between 2006 and 2012. However, vaccination coverage gaps may have contributed to recent measles outbreaks and may represent a serious barrier for Australia to maintain measles elimination status.

Barmah Forest virus (BFV) disease is the second most common mosquito-borne disease in Australia. Although the majority of notifications are received from Queensland, little is known about the distribution of the disease within the state, or the important mosquito vectors and nonhuman vertebrate hosts. We conducted a retrospective statistical analysis of the notifications received from Queensland residents from 1993 to 2003 to establish long-term local incidence rates and to identify disease outbreaks. In total, 4,544 notifications were received over the 10-yr period. Disease reporting peaked in autumn, although the peak transmission season encompassed both summer and autumn. Long-term standardized incidence rates for summer/autumn and winter/spring varied across the state, showing positive spatial autocorrelation in both 6-mo periods. Although 15 instances of increased disease activity were identified, only one major disease outbreak affecting eight contiguous local government areas was detected in summer/autumn 2002/2003. This outbreak contained 297 cases, 115 more than would be expected over this period. The factors important to this outbreak are unknown and require further investigation. Although the incidence rates for BFV disease are lower than Ross River virus disease, the most reported mosquito-borne disease in Australia, several factors indicate that this virus should be considered an important public health risk in Queensland. These include consistent endemic transmission, apparent underreporting of the disease, and the potential for outbreaks in major population centers.

Infection with the protozoan parasite Neospora caninum is an important cause of abortion in cattle. A major source of infection is transplacental transfer of the parasite from mother to offspring during pregnancy. This study describes investigations on the immunisation of outbred Qs mice before pregnancy with live or a crude lysate of N. caninum (NC-Nowra isolate) to prevent transplacental transfer of a challenge infection administered during pregnancy. Parasites present in the brains of pups from mice challenged with N. caninum (NC-Liverpool) were detected by PCR. Injection of live NC-Nowra tachyzoites before pregnancy dramatically reduced transplacental transfer from 75 to 0.8% in one experiment and from 76 to 8% in a second experiment. Injection of a crude lysate of NC-Nowra tachyzoites reduced transplacental transfer from 67 to 53% in one experiment and from 76 to 63% in a second experiment. Analysis of N. caninum-specific IgG1 and IgG2a antibody levels prior to pregnancy and challenge showed that NC-Nowra lysate induced a response skewed towards IgG1 whereas live parasites induced both IgG1 and IgG2a antibodies. After pregnancy and a challenge infection, a similar IgG1/IgG2a response was seen in all challenged groups. These results provide further positive support for the hypothesis that transplacental transmission of this parasite is preventable by vaccination. © 2005 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

OBJECTIVE: Data on the effectiveness of the diphtheria–tetanus–acellular pertussis (DTaP) vaccine in the first 4 years of life are sparse. We evaluated the vaccine effectiveness (VE) of 1 and 2 doses of DTaP before 6 months of age and of 3 doses from 6 months of age in Australia, where, since 2003, a fourth dose is not given until 4 years. METHODS: We matched reported pertussis cases aged 2 to 47 months between January 2005 and December 2009 to controls from a population-based immunization register by date of birth and region of residence. VE by number of doses and age group was calculated as (1 – odds ratio) × 100%. RESULTS: VE against hospitalization increased from 55.3% (95% confidence interval [CI], 42.7%–65.1%) for 1 dose before 4 months of age to 83.0% (95% CI, 70.2%–90.3%) for 2 doses before 6 months. The VE of 3 doses of DTaP against all reported pertussis was 83.5% (95% CI, 79.1%–87.8%) between 6 and 11 months, declining to 70.7% (95% CI, 64.5%–75.8%) between 2 and 3 years of age and 59.2% (95% CI, 51.0%–66.0%) between 3 and 4 years of age. CONCLUSIONS: DTaP provided good protection against pertussis in the first year of life from the first dose. Without a booster dose, the effectiveness of 3 doses waned more rapidly from 2 to 4 years of age than previously documented for children >6 years of age who had received 5 doses.

Estimates of the risk of intussusception (IS) associated with currently licensed rotavirus vaccines (RV1 [Rotarix; GSK] and RV5 [RotaTeq; Merck]) diverge. Contemporaneous introduction of both vaccines in Australia enabled a population-based assessment of risk.Confirmed cases of IS in infants aged 1 to12 months were identified from national hospitalization databases, supplemented by active hospital-based surveillance, from July 2007 through June 2010. Vaccination histories were verified by the Australian Childhood Immunisation Register, which was also used to identify age-matched controls. Self-controlled case series and case-control methods were used to assess the risk of IS associated with both vaccines in prespecified periods after vaccination. The estimated burden of vaccine-attributable IS was compared with estimated reductions in gastroenteritis hospitalizations.Based on 306 confirmed cases of IS, the relative incidence of IS in the 1-7-day period after the first vaccine dose, was 6.8 (95% confidence interval, 2.4-19.0; P.001) for RV1, and 9.9 (95% confidence interval, 3.7-26.4; P.001) for RV5. There was a smaller increased risk 1-7 days after the second dose of each vaccine. The case-control analysis gave similar results. We estimate an excess of 14 IS cases and6500 fewer gastroenteritis hospitalizations in young children annually in Australia after vaccine introduction.We found a similarly increased risk of IS after both vaccines, but the balance of benefits and risks at population level was highly favorable, a finding likely to extend to other settings despite varying incidence of IS and potentially higher morbidity and mortality from both gastroenteritis and IS.

To determine influenza vaccination coverage among pregnant women in New South Wales, and factors associated with vaccine uptake during pregnancy.Quantitative self-administered survey of pregnant women, using a non-random, stratified sample from antenatal clinics at three demographically diverse hospitals in NSW during the influenza season of 2011.Self-reported influenza vaccine uptake while pregnant; and attitudes, barriers and facilitators to vaccine acceptance during pregnancy.Of 939 women approached, 815 participated (87%). Influenza vaccine uptake in pregnant women was 27%. Women who had received a recommendation to have the vaccine were 20.0 times (95% CI, 10.9-36.9) more likely to have been vaccinated. Forty-two per cent recalled receiving a recommendation to be vaccinated. Other factors associated with vaccination were study site, perceived infection severity, overall feelings toward vaccination during pregnancy, vaccine accessibility, and willingness to take up the vaccine if recommended. Concern about the baby's safety was negatively associated with vaccination (odds ratio, 0.5; 95% CI, 0.2-0.9), but 68% (95% CI, 63%-71%) of women who expressed concern agreed they would have the vaccine if their health care professional recommended it.Recommendation from a health care provider is strongly associated with influenza vaccine uptake among pregnant women and can overcome their concerns about safety, but less than half the women surveyed reported receiving such a recommendation. Educational material targeting pregnant women and professional education and support for antenatal health care providers are needed to increase awareness and recommendation.

To assess changes in diagnostic practice and vaccine schedules for pertussis, we used culture-confirmation and clinical severity to compare pertussis cases at a single Australian tertiary pediatric hospital during relevant periods.We replicated the case ascertainment methods of a study reporting a 2-year epidemic period 1997-1999 (whole cell pertussis vaccine with 18-month booster, only culture available) to conduct a retrospective cross-sectional observational study over a 6-year period 2007-2012 (acellular pertussis vaccine, no 18-month booster, polymerase chain reaction and culture available). Cases were compared from case note review 2007-2012 (including prevalence of comorbidities) and published data 1997-1999.During 2007-2012, average annual hospitalizations in those aged6 months increased 2.3-fold (32.0 vs 14.0) and in those aged6 months by 5.1-fold (17.7 vs 3.5). Limited to culture-positive hospitalizations, there was no increase in those aged6 months (14.0 vs 14.5) contrasted with a 4.6-fold increase in those aged6 months (2.3 vs 0.5), despite increased annual culture requests (488 vs 188). In 2007-2012, significant comorbidities were documented in 41/72 (57%) hospitalized children aged ≥ 12 months vs 38/225 (17%)12 months (OR 6.5, 95% CI 3.7-11.7).Increased cases of culture-positive hospitalized pertussis were limited to fully immunized children6 months of age, consistent with schedule changes. Significant comorbidities were common, making a booster dose at 12-18 months of age especially important.

Objective This paper examines how the monovalent varicella vaccine for children, with an adolescent catch-up dose, was introduced into Australia's National Immunisation Program (NIP), focusing on programme implementation. Methods Semi-structured interviews were conducted with key informants involved in programme implementation. Key themes from interviews were identified through content analysis. Childhood coverage was assessed using data from the Australian Childhood Immunisation Register (ACIR) with adolescent coverage obtained from state/territory immunisation programmes. Seroprevalence data were analysed from national serosurveys conducted before and after programme commencement. Results Implementation challenges for both parents and providers included: (a) parental report of previous infection as an exclusion criterion; (b) introducing a vaccine on its own at 18 months of age; and (c) adding the adolescent dose into existing school-based vaccination programmes with parental reported exclusion criteria. Despite these challenges, coverage rapidly reached 83% by 24 months of age and 30–33% for the adolescent catch-up dose. When considered in conjunction with estimated pre-vaccination natural immunity in both target groups (20% and 83%, respectively) coverage can be considered high. The serosurvey under-estimated coverage in 2-year-old children but was useful to assess trends in population immunity. Conclusion The introduction of a single dose of monovalent varicella vaccine at 18 months of age and a school-based catch-up programme at 11–13 years of age successfully achieved high coverage, notwithstanding some challenges. Reported natural infection has been an exclusion criterion for vaccination, but as the programme matures and circulation of wild-type virus decreases, the need for this warrants consideration. There is a need for sensitive laboratory assays to measure vaccine-induced immunity at a population level.

The pertussis epidemic experienced in NSW in 2008–2009 was likely to be in part due to changes in diagnostic practice since 2007, which amplified disease notifications. We used population-based seroepidemiology as a less biased means of interpreting age-specific pertussis infection patterns in NSW from three serosurveys undertaken in 1997–98 (during an epidemic), 2002 (post-epidemic) and 2007 (inter-epidemic), using a standardised pertussis toxin IgG enzyme-linked immunosorbent assay (ELISA). There was a decrease in the proportion of high anti-pertussis toxin IgG titres (>62.5 ELISA Units/mL) across all age groups in the 2007 serosurvey compared to the previous two serosurveys. In the 2007 serosurvey, the proportion of undetectable (

BackgroundCross-sectional serosurveys using IgG antibody to pertussis toxin (IgG-PT) are increasingly being used to estimate trends in recent infection independent of reporting biases.Methods/principal findingsWe compared the age-specific seroprevalence of various levels of IgG-PT in cross-sectional surveys using systematic collections of residual sera from Australian diagnostic laboratories in 1997/8, 2002 and 2007 with reference to both changes in the pertussis vaccine schedule and the epidemic cycle, as measured by disease notifications. A progressive decline in high-level (≥62.5 EU/ml) IgG-PT prevalence from 19% (95% CI 16-22%) in 1997/98 to 12% (95% CI 11-14%) in 2002 and 5% (95% CI 4-6%) in 2007 was consistent with patterns of pertussis notifications in the year prior to each collection. Concomitantly, the overall prevalence of undetectable (Conclusions/significancePopulation seroprevalence of high levels of IgG-PT is accepted as a reliable indicator of pertussis disease activity over time within and between countries with varying diagnostic practices, especially in unimmunised age groups. Our novel findings suggest that increased prevalence of undetectable IgG-PT is an indicator of waning immunity useful for population level monitoring following introduction of acellular vaccines and/or schedule changes.

In 2008 and 2009 increased numbers of pertussis notifications were reported in NSW. During the epidemic period, the pertussis notification rate was 2.7 times higher than the previous 5-year average. Rates of pertussis notifications and hospitalisations were highest among infants aged less than 1 year across all years studied. Compared to previous years, the notification rate for children aged 1-4 years increased dramatically and was particularly striking for children aged 3 years with notifications exceeding those for infants in 2009. Changes in testing practices during the epidemic period, including a significant increase in the use of polymerase chain reaction, may account for some of the relative increase in size of the 2008-2009 outbreak compared with previous outbreak years.

Vaccine effectiveness in the first large-scale use of adolescent pertussis vaccine in Australia was evaluated by the screening method. Vaccine effectiveness was 78.0% (95% CI: 60.7-87.6%) for all study cases (n = 167), increasing to 85.4% (95% CI: 83.0-87.5%) for laboratory-confirmed cases (n = 155). Effectiveness should be comparable in settings with similar programs, such as the United States and Canada.

Objective: This study investigated the immunisation knowledge, attitudes and practices among health professionals in two regional Area Health Services of NSW with low and high immunisation rates. It also compared these factors between the areas and between the health professional groups. Methods: A self-administered questionnaire was posted in 2006 to health professionals, located within the North Coast and Hunter New England Area Health Services, whose practice could include immunisation. This included general practitioners (GPs), practice nurses, community nurses, hospital nurses and midwives. Results: Out of 926 surveys sent, 434 were returned (47%). The great majority of the health professionals (97%) believed that vaccines were safe, effective and necessary. However, in approximately one-third of respondents, there were specific concerns about additives, immune system overload and the number of vaccines. Significantly more health professionals in the North Coast area believed that additives in vaccines may be harmful and that adding more vaccines to the schedule would make immunisation too complex. Among GPs, over half felt uncomfortable about giving more than two injections at the one visit. Conclusions: Health professionals in this study had overall confidence in vaccines but had specific concerns about the number of vaccines given to children and vaccine content. These unfounded concerns may reduce parental confidence in immunisation. Implications: There is value in governments and immunisation support workers continuing their efforts to maintain up-to-date knowledge among health professionals and support the delivery of appropriate and targeted information to address concerns about vaccines.

Background. Representative population-based data on human papillomavirus (HPV) epidemiology are important for public health decision making but are difficult to obtain. Seroepidemiology is a valuable tool, although the relationship between HPV infection and seropositivity is incomplete.Methods. We obtained a large representative sample using residual diagnostic test serum samples obtained from individuals aged 0-69 years (1247 samples from male patients and 1523 samples from female patients) in Australia. Serum antibody levels to HPV types 6, 11, 16, and 18 were measured using an immunoassay.Results. Overall, seroprevalence of HPV types 6 and 16 was higher than seroprevalence of HPV types 11 and 18. Among female patients, peak HPV seropositivity occurred among those who were 30-39 years of age for types 6, 16, and 18 (22%, 22%, and 10.5%, respectively) and among those who were 40-49 years of age for HPV 11 (11.8%). Among male subjects, peak HPV seropositivity occurred among those who were 40-49 years of age for types 6 and 11 (15.4% and 9.1%, respectively) and among those who were 50-59 years of age for types 16 and 18 (14.3% and 8.2%, respectively). No cases of HPV seropositivity were detected in individualsConclusions. Australian seroepidemiological data, showing differing age-specific patterns of HPV seropositivity in male and female patients, are likely to be generalizable to other developed countries and add to other data supporting completion of HPV vaccination before adolescence.

Abortion, resulting from infections by the parasite Neospora caninum, is a major cause of economic loss to both the dairy and beef industries of cattle-producing countries of the world. Vaccination as a means of preventing abortion and/or infection represents a viable control strategy; indeed a commercial vaccine is available in some countries, albeit of unknown efficacy. The commercial vaccine is based on inactivated tachyzoites of N. caninum but other approaches based on lysates and recombinant antigens of N. caninum may also be feasible. In this study we have used an immunisation/challenge model of transplacental transmission, based on the Qs mouse with an Nc-Liverpool challenge, to investigate the vaccine potential of a number of formulations based on four recombinant proteins of N. caninum (GRA1, GRA2, MIC10, and p24B). All formulations studied were immunogenic in the mouse when assessed by ELISA using sonicated tachyzoite antigen as the target antigen. In one experiment, a mixture of MIC10 and p24B produced partial protection against transplacental transmission of N. caninum in this mouse model; in contrast a live infection of tachyzoites of NC-Nowra given before pregnancy always induces very high levels of protective immunity. The field of vaccines against Neospora-associated abortion in cattle is discussed. © 2008 Elsevier Ltd. All rights reserved.

Important changes have occurred in the National Immunisation Program for pertussis during the decade 1995-2005, including the introduction of acellular pertussis vaccine for all doses, removal from the schedule of the booster dose at 18 months, and the introduction of a booster dose for adolescents. In addition, the coverage of pertussis vaccine at 12 and 24 months has substantially increased as recorded by Australian Bureau of Statistics surveys and the Australian Childhood Immunisation Register. There were 75,458 notifications nationally between 1995 and 2005, with little change in the annual number of notifications at the national level but with periodic and dramatic changes in the age distribution of notified cases. Pertussis is well controlled in the 1-4 and 5-9 year age groups, and the highest annual notification rates continue to be in infants under 6 months of age. Adolescents aged 10-19 years had high notification rates in all states and territories, over this period, but 63% of notifications are now in the 20-59 year age range. Following the introduction of a fifth dose for adolescents, the current focus should be on protecting infants too young to be vaccinated and further defining the true morbidity of the disease in the elderly population.

Notification trends from countries with well-established immunisation programs show increasing tetanus cases among the elderly, corresponding to seroepidemiologic data showing declining immunity with advanced age. We examined Australian trends in tetanus to review the likely value of routine funded immunisation at 65 years. Since 1993, 62% (36/58) of notifications, 44% (67/151) of hospitalisations and 83% (10/12) of deaths were in people aged over 65 years. Taking into account higher vaccine coverage at 65 years, versus the current recommended age in Australia of 50 years, we estimate that routine funded tetanus vaccine would prevent 9% more hospitalisations and 28% more deaths than the most favourable outcome from the current unfunded recommendation at 50 years. This is likely to be applicable to other industrialised countries.

In 2004, 60 diseases and conditions were nationally notifiable in Australia. States and Territories reported a total of 110,929 cases of communicable diseases to the National Notifiable Diseases Surveillance System (NNDSS): an increase of 4 per cent on the number of notifications in 2003. In 2004, the most frequently notified diseases were sexually transmissible infections (46,762 cases; 42% of total notifications), gastrointestinal diseases (25,247 cases; 23% of total notifications) and bloodborne diseases (19,191 cases; 17% of total notifications). There were 13,206 notifications of vaccine preventable diseases, 6,000 notifications of vectorborne diseases, 1,799 notifications of other bacterial infections (includes, legionellosis, leprosy, meningococcal infections and tuberculosis) and 877 notifications of zoonotic diseases.

Neospora caninum is an obligate intracellular protozoan parasite which is efficiently transmitted transplacentally in cattle where it may cause abortion. A pregnant mouse model was used to characterise the immune response following N. caninum infection; the response in non-pregnant and pregnant mice was compared. Spleen cells from both infected/non-pregnant and infected/pregnant mice produced interferon-gamma, interleukin-12 and tumour necrosis factor alpha; however, the levels of these Th1 cytokines were lower in infected/pregnant mice. Infected/non-pregnant and infected/pregnant mice also produced the Th2 cytokine interleukin-10; however, there was no trend toward a decrease of this in pregnant mice. Interleukin-4 was exclusively produced at high levels by infected/pregnant mice and thus appears responsible for the observed decline in Th1 cytokine production in pregnant mice. A bias towards Th2 cytokines such as IL-4 and IL-10 is normally associated with the maintenance of a viable pregnancy, and not with the control of protozoal infections. Consequently, the importance and role of cytokines and cell-mediated immunity in the control of transplacental transmission and foetal loss due to N. caninum infection are discussed.

Resistance to many intracellular protozoan parasites is dependent on T helper cell 1 cytokine responses. This has important repercussions for pregnant females because strong T helper cell 1 cytokine responses are incompatible with successful pregnancy. Thus, there are two possible consequences of infection with protozoans such as Leishmania major, Plasmodium falciparum and Toxoplasma gondii during pregnancy: (1) pregnancy is compromised; or (2) resistance to the parasite is compromised. The apicomplexan Neospora caninum is a parasite renowned for its association with abortion in cattle. Furthermore, a major route of transmission for this parasite is congenital. The evidence for the hypothesis that T helper cell 1 cytokines play a role in these events is reviewed here.

Fetal loss and vertical transmission of Neospora caninum were evaluated in outbred Quackenbush (Qs) mice with respect to dose of parasites, N. caninum isolate, and route of injection. Mice were infected with NC-Liverpool or NC-SweB1 at day 5 or 8 of pregnancy with doses of 10(4), 10(6), or 10(7) parasites, through either a subcutaneous or intraperitoneal injection. Polymerase chain reaction was used to detect N. caninum in the brains of offspring, and enzyme-linked immunosorbent assay was used to analyze the maternal immune response. Vertical transmission occurred in mice given 10(6) NC-Liverpool at day 5 during gestation, and a significant (P0.05) maternal antibody response was observed in mice infected with NC-Liverpool or NC-SweB1 at days 5 and 8 of gestation. This study shows that outbred Qs mice are a useful model for the study of vertical transmission associated with N. caninum, as they display less clinical disease and pathogenesis than inbred mice and have large litters, which is advantageous when studying maternal transmission.

Over the past decade the number of recommended and funded vaccines for adolescents has increased, becoming a substantial part of the National Immunisation Program in Australia. In response, NSW has implemented disease-specific vaccination campaigns for both children and adolescents and more recently established a routine high school-based vaccination program to administer vaccines to this often hard to reach group. This paper outlines the history of school-based vaccination in NSW from its commencement in 1971 to coverage from early disease-specific programs, and describes the implementation of the current program of routine vaccination. Substantial coverage has been achieved across the age spectrum 5-17 years, highlighting the effectiveness of the school-based vaccination program in reaching large numbers of adolescents.

Summary Background Infection with Helicobacter pylori is common worldwide and a significant cause of upper gastrointestinal disease. Prevalence of this infection varies in different population groups internationally. Because of the invasiveness of specimen collection for bacteriologic diagnosis and the expense of tests such as labeled urea breath tests, serology is the most feasible means of determining the population epidemiology of H. pylori . The aim of this study was to describe the seroepidemiology of H. pylori infection in Australia. Methods H. pylori -specific ELISA for the presence of IgG antibodies was performed on a representative sample of 2413 sera from Australia in 2002, using validated serosurveillance methods. Results The overall seroprevalence of H. pylori infection in Australia was 15.1% in 2002, with no statistical difference between genders. Seropositivity rates increased progressively with age, ranging between 4.0% in the 1–4-year-olds and 23.3% in the 50–59-year-olds. Conclusions The prevalence of infection with H. pylori in Australia was lower than rates reported in other developed countries, at 15.4%. This study provides important baseline measurements for future preventive measures including vaccine research and development. Further studies to determine subgroups at higher risk of infection may help target the more susceptible populations.

Background The availability of new pneumococcal conjugate vaccines covering a broader range of serotypes, has seen many countries introduce these into their national immunisation program. When transitioning from 7-valent to 13-valent pneumococcal conjugate vaccines, Australia is one of a small number of countries that included a supplementary dose of the 13-valent pneumococcal conjugate vaccine to offer protection against additional serotypes to an expanded age group of children. An evaluation of the implementation and uptake of the 13-valent pneumococcal conjugate vaccine supplementary dose was undertaken in two local health districts (LHDs) in New South Wales, Australia. Methods A self-administered postal survey of immunisation providers in the Northern New South Wales and Mid North Coast LHDs. Trends in vaccine ordering were examined. Coverage was assessed using data from the Australian Childhood Immunisation Register (ACIR). Results Of the 177 surveys sent, 125 were returned (70%). Almost all providers (96%) were aware of the 13vPCV supplementary dose program though took an opportunistic approach to program promotion and parental reminders. Supplementary doses of 13vPCV were ordered for 37% of the eligible cohort, mostly in the program’s first six months. Coverage as recorded on the ACIR was 27%, though was lower in older children and those not due for scheduled childhood vaccines. Of the children who received the 13vPCV supplementary dose, 3% received it at the same time as vaccines due at 12-months of age, and 44% at the time of those due at 18-months of age. Conclusion Despite the high awareness of the program, reported coverage was lower than that for other PCV supplementary dose programs in Australia and internationally. This may be influenced by providers’ largely opportunistic approach to implementation, under-reporting to the ACIR or vaccine uptake. Lessons learned from this evaluation are relevant for future time-limited childhood vaccination programs. Prior to commencement, providers should be informed about the importance of catch-up/supplementary vaccination for their patients and their active role in promoting this. They should also receive program information before parents. An understanding of parental reasons for non-receipt of time-limited childhood vaccines and evaluation of the effect of aligning supplementary (or catch up) vaccination programs with the NIP schedule would be useful to inform future programs.