Search

Background and Objectives: Group B Streptococcus (GBS) is the leading cause of sepsis and meningitis in infants <90 days. In this study, the burden of GBS disease and mortality in young infants in England was assessed., Methods: Using linked hospitalization records from every National Health Service (NHS) hospital from April 1, 1998 to March 31, 2017, we calculated annual GBS incidence in infants aged <90 days and, using regression models, compared their perinatal factors, rates of hospital-recorded disease outcomes, and all-cause infant mortality rates with those of the general infant population., Results: 15 429 infants aged <90 days had a hospital-recorded diagnosis of GBS, giving an average annual incidence of 1.28 per 1000 live births (95% CI 1.26-1.30) with no significant trend over time. GBS-attributable mortality declined significantly from 0.044 (95% CI .029-.065) per 1000 live births in 2001 to 0.014 (95% CI .010-.026) in 2017 (annual percentage change -6.6, 95% CI -9.1 to -4.0). Infants with GBS had higher relative rates of visual impairment (HR 7.0 95% CI 4.1-12.1), cerebral palsy (HR 9.3 95% CI 6.6-13.3), hydrocephalus (HR 17.3 95% CI 13.8-21.6), and necrotizing enterocolitis (HR 18.8 95% CI 16.7-21.2) compared with those without GBS., Conclusions: Annual rates of GBS disease in infants have not changed over 19 years. The reduction in mortality is likely multifactorial and due to widespread implementation of antibiotics in at-risk mothers and babies, as well as advances in managing acutely unwell infants. New methods for prevention, such as maternal vaccination, must be prioritized., (© The Author(s) 2020. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Background: After the re-emergence of serogroup C meningococcal meningitis (MM) in Nigeria and Niger, we aimed to re-evaluate the vaccination policy used to respond to outbreaks of MM in the African meningitis belt by investigating alternative strategies using a lower incidence threshold and information about neighboring districts., Methods: We used data on suspected and laboratory-confirmed cases in Niger and Nigeria from 2013 to 2017. We calculated global and local Moran's I-statistics to identify spatial clustering of districts with high MM incidence. We used a Pinner model to estimate the impact of vaccination campaigns occurring between 2015 and 2017 and to evaluate the impact of 3 alternative district-level vaccination strategies, compared with that currently used., Results: We found significant clustering of high incidence districts in every year, with local clusters around Tambuwal, Nigeria in 2013 and 2014, Niamey, Niger in 2016, and in Sokoto and Zamfara States in Nigeria in 2017.We estimate that the vaccination campaigns implemented in 2015, 2016, and 2017 prevented 6% of MM cases. Using the current strategy but with high coverage (85%) and timely distribution (4 weeks), these campaigns could have prevented 10% of cases. This strategy required the fewest doses of vaccine to prevent a case. None of the alternative strategies we evaluated were more efficient, but they would have prevented the occurrence of more cases overall., Conclusions: Although we observed significant spatial clustering in MM in Nigeria and Niger between 2013 and 2017, there is no strong evidence to support a change in methods for epidemic response in terms of lowering the intervention threshold or targeting neighboring districts for reactive vaccination., (© The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America.)

Background: To identify the barriers and facilitators to uptake of the HPV vaccine in an ethnically diverse group of young women in the south west of England., Methods: Three school-based vaccination sessions were observed. Twenty-three young women aged 12 to 13 years, and six key informants, were interviewed between October 2012 and July 2013. Data were analysed using thematic analysis and the Framework method for data management., Results: The priority given to preventing cervical cancer in this age group influenced whether young women received the HPV vaccine. Access could be affected by differing levels of commitment by school staff, school nurses, parents and young women to ensure parental consent forms were returned. Beliefs and values, particularly relevant to minority ethnic groups, in relation to adolescent sexual activity may affect uptake. Literacy and language difficulties undermine informed consent and may prevent vaccination., Conclusions: The school-based HPV vaccination programme successfully reaches the majority of young women. However, responsibility for key aspects remain unresolved which can affect delivery and prevent uptake for some groups. A multi-faceted approach, targeting appropriate levels of the socio-ecological model, is required to address procedures for consent and cultural and literacy barriers faced by minority ethnic groups, increase uptake and reduce inequalities., (© The Author 2015. Published by Oxford University Press on behalf of Faculty of Public Health.)

Background: In 2010, mass vaccination with a then-new meningococcal A polysaccharide-tetanus toxoid protein conjugate vaccine (PsA-TT, or MenAfriVac) was undertaken in 1- to 29-year-olds in Bamako, Mali. Whether vaccination with PsA-TT effectively boosts tetanus immunity in a population with heterogeneous baseline tetanus immunity is not known. We assessed the impact of PsA-TT on tetanus toxoid (TT) immunity by quantifying age- and sex-specific immunity prior to and 2 years after introduction., Methods: Using a household-based, age-stratified design, we randomly selected participants for a prevaccination serological survey in 2010 and a postvaccination survey in 2012. TT immunoglobulin G (IgG) antibodies were quantified and geometric mean concentrations (GMCs) pre- and postvaccination among all age groups targeted for vaccination were compared. The probability of TT IgG levels ≥0.1 IU/mL (indicating short-term protection) and ≥1.0 IU/mL (indicating long-term protection) by age and sex was determined using logistic regression models., Results: Analysis of 793 prevaccination and 800 postvaccination sera indicated that while GMCs were low pre-PsA-TT, significantly higher GMCs in all age-sex strata were observed 2 years after PsA-TT introduction. The percentage with short-term immunity increased from 57.1% to 88.4% (31.3-point increase; 95% confidence interval [CI], 26.6-36.0;, P < .0001) and with long-term immunity increased from 20.0% to 58.5% (38.5-point increase; 95% CI, 33.7-43.3; P < .0001) pre- and postvaccination., Conclusions: Significantly higher TT immunity was observed among vaccine-targeted age groups up to 2 years after Mali's PsA-TT mass vaccination campaign. Our results, combined with evidence from clinical trials, strongly suggest that conjugate vaccines containing TT such as PsA-TT should be considered bivalent vaccines because of their ability to boost tetanus immunity., (© The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America.)

Background: The introduction of MenAfriVac in campaigns targeting people aged 1-29 years across the African meningitis belt has successfully reduced meningitis incidence and carriage due to Neisseria meningitidis group A (MenA). It is important to consider how best to sustain population protection in the long term., Methods: We created a mathematical model of MenA transmission and disease to investigate the potential impact of a range of immunization strategies. The model is age structured; includes classes of susceptible, carrier, ill, and immune people (who may be vaccinated or unvaccinated); and incorporates seasonal transmission and a stochastic forcing term that models between year variation in rates of transmission. Model parameters were primarily derived from African sources. The model can describe the typical annual incidence of meningitis in the prevaccine era, with irregular epidemics of varying size. Parameter and structural uncertainty were explored in sensitivity analyses., Results: Following MenAfriVac introduction at high uptake, the model predicts excellent short-term disease control. With no subsequent immunization, strong resurgences in disease incidence were predicted after approximately 15 years (assuming 10 years' average vaccine protection). Routine immunization at 9 months of age resulted in lower average annual incidence than regular mass campaigns of 1- to 4-year-olds, provided coverage was above approximately 60%. The strategy with the lowest overall average annual incidence and longest time to resurgence was achieved using a combination strategy of introduction into the Expanded Programme on Immunization at 9 months, 5 years after the initial mass campaigns, with a catch-up targeting unvaccinated 1- to 4-year-olds., Conclusions: These results can be used to inform policy recommendations for long-term vaccination strategies with MenAfriVac., (© The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America.)

Background: A group A meningococcal (MenA) conjugate vaccine, PsA-TT (MenAfriVac), was introduced in Burkina Faso via mass campaigns between September and December 2010, targeting the 1- to 29-year-old population. This study describes specific antibody titers in the general population 11 months later and compares them to preintroduction data obtained during 2008 using the same protocol., Methods: During October-November 2011, we recruited a representative sample of the population of urban Bobo-Dioulasso aged 6 months to 29 years, who underwent standardized interviews and blood draws. We assessed anti-MenA immunoglobulin G (IgG) concentrations (n = 200) and, using rabbit complement, serum bactericidal antibody (SBA) titers against 2 group A strains: reference strain F8238 (SBAref) (n = 562) and strain 3125 (SBA3125) (n = 200)., Results: Among the 562 participants, 481 (86%) were aged ≥23 months and had been eligible for the PsA-TT campaign. Among them, vaccine coverage was 86.3% (95% confidence interval [CI], 82.7%-89.9%). Prevalence of putatively protective antibodies among vaccine-eligible age groups was 97.3% (95% CI, 95.9%-98.7%) for SBAref titers ≥128, 83.6% (95% CI, 77.6%-89.7%) for SBA3125 ≥128, and 84.2% (95% CI, 78.7%-89.7%) for anti-MenA IgG ≥2 µg/mL. Compared to the population aged 23 months to 29 years during 2008, geometric mean titers of SBAref were 7.59-fold higher during 2011, 51.88-fold for SBA3125, and 10.56-fold for IgG., Conclusions: This study shows high seroprevalence against group A meningococci in Burkina Faso following MenAfriVac introduction. Follow-up surveys will provide evidence on the persistence of population-level immunity and the optimal vaccination strategy for long-term control of MenA meningitis in the African meningitis belt., (© The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America.)

Background: The human papillomavirus (HPV) vaccine offers an opportunity to reduce health inequalities associated with cervical cancer provided the vaccine is delivered equitably at population level. Method We reviewed evidence of inequalities in HPV vaccine uptake in young women after undertaking a comprehensive search of databases from inception to March 2012. Studies that compared HPV vaccination initiation and/or completion by at least one ethnicity or socioeconomic-related variable in adolescent young women were included. There were no language restrictions. Data were extracted by two reviewers and pooled in a meta-analysis using a random-effects model; sub-analyses and meta-regression were undertaken to investigate sources of heterogeneity., Results: In all, 29 publications related to 27 studies were included in the review. Black young women were less likely to initiate HPV vaccination compared with White young women (combined OR: 0.89, 95% CI: 0.82-0.97). In the USA, young women without healthcare insurance were less likely to initiate (combined OR: 0.56, 95% CI: 0.40-0.78). There was no strong evidence that lower family income (combined OR: 1.16, 95% CI: 1.00-1.34) or lower parental education (combined OR 1.06, 95% CI: 0.92-1.22) influenced HPV vaccination initiation., Conclusions: We found strong evidence for differences in HPV vaccination initiation by ethnicity and healthcare coverage, but did not find a strong association with parental education or family income variables. The majority of studies originated from the USA. Population-based studies reporting both initiation and completion of the HPV vaccination programme are required to establish patterns of uptake in different healthcare contexts.

At the end of 2005, six European countries had implemented public immunization campaigns with serogroup C conjugate vaccines, and all had experienced substantial declines in the incidence of serogroup C disease. A quadrivalent ACWY meningococcal vaccine is in use in the USA, but serogroup A is extremely rare in Europe and serogroups Y and W135 are infrequent causes of disease. This paper outlines recommendations on the use of conjugate vaccines in Europe based on the experience with meningococcal C conjugate (MCC) vaccines so far.

Between 1999 and 2004, the European Union Invasive Bacterial Infections Surveillance Network (EU-IBIS) received c. 50,000 reports of meningococcal disease from 27 participating countries. Analysis has demonstrated a major decline in the incidence of invasive disease in those countries that have introduced routine vaccination against serogroup C infection. The establishment of rapid reporting of W135 and B2a/B2b strains has been able to provide early reassurance that these strains are not emerging as major public health problems in Europe. Between September 2001 and February 2005, the EU-MenNet project offered further opportunities for enhancing this data resource. Collaborative projects included: improving the EU-IBIS website; reviewing case ascertainment in Europe; reviewing cost-effectiveness studies for meningococcal serogroup C conjugate (MCC) vaccination; international comparisons of MCC vaccine efficacy; and mathematical modelling studies. In addition, linking of data from the European Meningococcal Multi-locus Sequence Type Centre to epidemiological data was performed. Particular clonal complexes were found to be preferentially associated with certain serogroups. Case fatality was also found to vary with clonal complex, suggesting that genotype can be a marker for hypervirulence. The importance of close collaboration between networks of epidemiologists, microbiologists, and the wider scientific and public health community is demonstrated.

Much interest has surrounded the use of conjugate vaccines in recent years, with the development of vaccines against disease caused by Haemophilus influenzae type b, Neisseria meningitidis, and Streptococcus pneumoniae. These vaccines offer the potential for safe and effective disease control, but some questions remain, particularly regarding the duration and mechanisms of protection and the longer-term impact of vaccination on carriage. In this paper, the authors use data on immunization with serogroup C meningococcal conjugate vaccines in England and Wales to develop and apply a mathematical model to investigate the direct and indirect (herd immunity) effects of a conjugate vaccine program. A realistic, age-structured, dynamic model was developed and parameterized and was fitted to epidemiologic data from England and Wales. The effects of a range of vaccine strategies, including hypothetical scenarios, were investigated. The basic reproduction number was estimated to be 1.36. Catch-up vaccination targeting teenagers generated substantial herd immunity and was important in controlling disease rapidly. The results were sensitive to changes in the assumptions regarding the method of vaccine action, particularly duration of protection and efficacy of vaccination against carriage acquisition. This model can be used to help predict the potential impact of vaccine strategies both in the United Kingdom and elsewhere.