Uptake and determinants of routine immunization among vulnerable children and adolescents in sub-Saharan Africa: A scoping review

BACKGROUND

Despite notable improvements in coverage of immunization services in sub-Saharan Africa (SSA) over recent decades, there are marked inequities across populations. We undertook a scoping review to study the uptake and determinants of routine immunization (RI). This is the health system component that regularly delivers vaccination services to eligible populations as set out in national immunization schedules among vulnerable children and adolescents in sub-Saharan Africa.

METHODS

We adopted the population-concept-context format to address the 2 research questions. The population was vulnerable children and adolescents from birth to 18 years from 2010 to 2020. The context was sub-Saharan Africa. An electronic search was conducted in PubMed, SCOPUS and African Journals Online, following which the selected studies were entered into a data extraction tool. Estimates of immunization uptake as well as quantitative and qualitative synthesis of demand and supply determinants of immunization were carried out.

RESULTS

Out of the 6040 studies screened, 68 articles were finally selected. Nineteen of these focused on older children and adolescents (9-18 years). RI uptake ranged from 1/201 (0.01 %; 95 % CI:0.01-0.03) to 205/216 (95 %; 95 % CI:0.92-0.97). Demand-related factors that were positively correlated with RI uptake were non-Muslim religion (aOR:1.56,95 % CI:1.11-2.17), high caregiver vaccination knowledge (aOR:3.30,95 % CI:0.26-3.56), high household socio-economic status (aOR:1.25,95 % CI:1.04-1.49) and short distance from health facility (aOR:1.63,95 % CI:1.10-2.39). Attendance of less than 4 antenatal visits (aOR:0.47,95 %CI:0.32-0.67) and Somali ethnicity (aOR:0.41,95 %CI:0.19-0.91) were negatively associated with RI uptake. Only 3 quantitative studies examined supply determinants of immunization uptake. Conducive health facility attributes were positively correlated with RI uptake (aOR:2.21,95 % CI:1.22-3.98) while the cost of obtaining vaccination (aOR:1.01,95 % CI:0.63-1.60) and health worker shortage (aOR:0.33,95 % CI:0.02-0.13) were negatively correlated.

CONCLUSION

RI uptake among vulnerable sub-populations of children and adolescents varies widely. There is a paucity of studies on supply-side determinants of routine immunization uptake and also among adolescents.

Respiratory syncytial virus vaccination and immunoprophylaxis: realising the potential for protection of young children

The search for safe and efficacious products to prevent severe respiratory syncytial virus (RSV) disease in young infants has lasted more than 60 years. In high-income and middle-income countries, two new products have been authorised: an RSV monoclonal antibody for administration to infants (nirsevimab) and an RSV prefusion F maternal vaccine (RSVpreF [Pfizer, Puurs, Belgium]) for administration to pregnant people. These products are not yet available in low-income and lower-middle-income countries, where most RSV deaths occur. Other papers in this Series describe the acute burden of RSV disease in young children, the effects of RSV infection in early childhood on long-term lung health, and the burden of RSV disease and disease prevention products in older adults. In this Series paper, we briefly review the efficacy, effectiveness, and safety of nirsevimab and RSVpreF maternal vaccine for protection of infants. We then explore potential regulatory, policy, and implementation pathways and provide case studies of intervention uptake in Spain and Argentina, and considerations for use in Kenya. We also explore the health economic evidence to inform product introduction decisions. With sufficient political will and affordable pricing, RSV disease prevention in infants can become a global reality.

New Vaccine Introductions in WHO African Region between 2000 and 2022

Significant progress has been made in vaccine development worldwide. This study examined the WHO African Region's vaccine introduction trends from 2000 to 2022, excluding COVID-19 vaccines. We extracted data on vaccine introductions from the WHO/UNICEF joint reporting form for 17 vaccines. We examined the frequency and percentages of vaccine introductions from 2000 to 2022, as well as between two specific time periods (2000-2010 and 2011-2022). We analysed Gavi eligible and ineligible countries separately and used a Chi-squared test to determine if vaccine introductions differed significantly. Three vaccines have been introduced in all 47 countries within the region: hepatitis B (HepB), Haemophilus influenzae type b (Hib), and inactivated polio vaccine (IPV). Between 2011 and 2022, HepB, Hib, IPV, the second dose of measles-containing vaccine (MCV2), and pneumococcal conjugate vaccine (PCV) were the five most frequently introduced vaccines. Hepatitis A vaccine has only been introduced in Mauritius, while Japanese encephalitis vaccine has not been introduced in any African country. Between 2000-2010 and 2011-2022, a statistically significant rise in the number of vaccine introductions was noted (p < 0.001) with a significant positive association between Gavi eligibility and vaccine introductions (p < 0.001). Significant progress has been made in the introduction of new vaccines between 2000 and 2022 in the WHO African Region, with notable introductions between 2011 and 2022. Commitments from countries, and establishing the infrastructure required for effective implementation, remain crucial.

Status of New Vaccine Introduction - Worldwide, 2016-2021

This report describes the status of introductions globally for eight World Health Organization (WHO)-recommended new and underutilized vaccines, comprising 10 individual vaccine antigens. By 2021, among 194 countries worldwide, 33 (17%) provided all of these 10 WHO-recommended antigens as part of their routine immunization schedules; only one low-income country had introduced all of these recommended vaccines. Universal hepatitis B birth dose; human papillomavirus vaccine; rotavirus vaccine; and diphtheria, tetanus, and pertussis-containing vaccine first booster dose have been introduced by 57%, 59%, 60%, and 72% of all countries worldwide, respectively. Pneumococcal conjugate vaccine, rubella-containing vaccine, measles-containing vaccine second dose, and Haemophilus influenzae type b vaccine have been introduced by 78%, 89%, 94%, and 99% of all countries, respectively. The annual rate of new vaccine introductions declined precipitously when the COVID-19 pandemic started, from 48 in 2019 to 15 in 2020 before rising to 26 in 2021. Increased efforts to accelerate new and underutilized vaccine introductions are urgently needed to improve universal equitable access to all recommended vaccines to achieve the global Immunization Agenda 2021-2030 (IA2030) targets.

The prevalence and influencing factors of the oropharyngeal carriage of Haemophilus influenzae in healthy children in a high-altitude area of China: A cross-sectional study

Haemophilus influenzae is a common commensal organism of the human upper respiratory tract and an important cause of human disease. No data on H influenzae carriage rate has been carried out on the Qinghai-Tibet Plateau of China. This study aims to present the H influenzae carriage rate and influencing factors of H influenzae in healthy children <15 years of age in Qinghai Province, an area located on the Qinghai-Tibet Plateau in China. Oropharyngeal swabs for the detection of H influenzae DNA were collected between September and October 2019. Taqman real-time polymerase chain reaction was used to detect the nucleic acids from the oropharyngeal swabs. Self-designed questionnaires were used to investigate the related information among this group of children. A number of 284 children were enrolled in this study. The carriage rate of H influenzae was 44.7%. The carriage rate in cities was 47.5%, in rural areas was 21.9%, and in pastoral areas was 52.8%. The carriage rate was found to be higher among children of minority ethnic groups than those of Han ethnicity (55.6% vs 38.1%). H influenzae carriage rate was influenced by tobacco smoke exposure (adjusted odds ratio [aOR] = 2.31, 95% CI [confidence interval]: 1.14-4.70), having siblings <5 years of age (aOR = 2.36, 95% CI: 1.21-4.59), respiratory infections during the last 30 days (aOR = 2.37, 95% CI: 1.11-5.06), and parent/guardian education level (aOR = 0.08, 95% CI: 0.02-0.27). H influenzae was highly prevalent in healthy children in Qinghai Province, especially among children of minority ethnicities and those living in pastoral areas. Tobacco smoke exposure, having siblings <5 years of age, and respiratory infections during the last 30 days were risk factors for H influenzae carriage. Parents or guardians having education levels of college or higher was a protective factor for H influenzae carriage. It is of critical importance that the government take effective measures to reduce the carriage rate and the occurrence of H influenzae related diseases in susceptible populations.

Criteria for New Vaccine Introduction in a National Expanded Program on Immunization: A Survey of Expanded Program on Immunization Managers

OBJECTIVES

This study aimed to critically review the decision-making (DM) processes for new vaccines introduction in Latin America's Expanded Program on Immunization (EPIs) and role of cost-effectiveness analyses (CEAs).

METHODS

An online survey was conducted between August and December 2019 to Latin America and the Caribbean (LAC) EPI managers, participants of the National Immunization Technical Advisory Group (NITAG). Information about criteria to introduce the most recent vaccine was asked. CEA role in that decision and technical knowledge of informants were investigated. Frequencies of categorical data were calculated. Bar plots and stacked bar plots were used to visualize the data.

RESULTS

A total of 26 EPI managers and stakeholders participated in the survey from 14 LAC countries. Respondents worked at the Ministry of Health and the Pan American Health Organization. Most recent vaccines included were human papillomavirus (42.3%), injectable polio (26.9%), and varicella (15.4%). High burden of disease and cost-effectiveness/cost-utility were identified as the main a priori criteria used to new vaccine introduction, but not all inputs are available or good quality. Discussion about vaccine introduction was conducted at NITAG meetings, reported as independent by most countries. Nevertheless, NITAG members did not master the essential CEAs concepts.

CONCLUSIONS

DM of vaccine introduction in LAC is reported by EPI managers as a process of discussion with participation of several actors where economic rationalities had a high role in the decision. It is necessary to strengthen the technical capacity to understand economical inputs to inform DM and advocate to include other rationalities as important in the discussion.

Building evidence for improving vaccine adoption and uptake of childhood vaccinations in low- and middle-income countries: a systematic review

Vaccine coverage for children is an important indicator of the performance of national health and immunization systems. Most of the existing literature has targeted mothers’ low educational level, living in underserved districts and/or remote rural areas and economic poverty that are correlated with low immunization coverage but the supply- and demand-side constraints to immunization in low- and middle- income countries (LMICs) are not well understood. The reliability of claimed administrative immunization coverage in these contexts is questionable. To address these barriers within the present Expanded Programme on Immunization (EPI), the difficulties related to inadequate vaccination uptake must be addressed in more depth. Building on already produced literature, this study aims to determine the extent of immunization coverage among children in LMICs, as well as to fill in the gaps in awareness about system-level obstacles that currently hinder the effective delivery and uptake of immunization services through EPI. By two reviewers, a literature search using PubMed and Google Scholar along with targeted grey literature was conducted on the 2nd of June 2021 by following PRISMA guidelines. The search techniques for electronic databases used both Medical Subject Headings (Mesh) and free-text words were tailored to each database's specific needs using a controlled vocabulary that was limited to the English language from 2000 and 2020. Of the 689 records, eleven articles were included in this review meeting the inclusion criteria. In total, five articles related to vaccination coverage, four studies on components of the routine immunization system, one article on the implementation of new and under-utilized vaccines and one were on vaccines financing. We evaluated the quality of the included studies and extracted into tables created by one investigator and double-checked by another. Review findings suggest that specific strategies to reduce inequality may be required. Vaccine procurement and pricing strategies, as well as vaccine customization to meet the needs of LMICs, are all critical components in strengthening immunization systems. Our findings could be used to establish practical strategies for countries and development partners to address coverage gaps and improve vaccination system effectiveness.

Is the Rotavirus Vaccine Really Associated with a Decreased Risk of Developing Celiac and Other Autoimmune Diseases?

This review examines the risk of developing celiac disease (CD) and other autoimmune diseases in individuals receiving the rotavirus (RV) vaccine compared to the normal population. Celiac disease is a malabsorptive, chronic, immune-mediated enteropathy involving the small intestine. The pathogenesis of CD is multifactorial, and mucosal immunity plays an important role in its development. Low mucosal IgA levels significantly increase the risk of developing the disease. Rotavirus is an infectious agent that causes diarrhea, particularly in children aged 0-24 months, and is frequently involved in diarrhea-related deaths in these children. An oral vaccine against RV has been developed. While it is effective on RV infection, it also contributes to increasing mucosal immunity. Studies have indicated that individuals immunized with the RV vaccine are at lower risk of developing CD than unvaccinated individuals. In addition, the mean age for developing CD autoimmunity may be higher in the vaccinated group than in controls receiving placebo. Additional studies that include children immunized with different RV vaccines and unvaccinated children would provide more meaningful results. Although current data suggest a possible association of RV vaccination with a reduced risk of developing CD and other autoimmune diseases, this remains an unanswered question that merits greater international investigation.

Global Rotavirus and Pneumococcal Conjugate Vaccine Introductions and the Association With Country Disease Surveillance, 2006-2018

BACKGROUND

To inform the introduction of pneumococcal conjugate vaccine (PCV) and rotavirus vaccine, the World Health Organization (WHO) established the Global Invasive Bacterial Vaccine-Preventable Disease Surveillance Network (GISN) and the Global Rotavirus Surveillance Network (GRSN) in 2008. We investigated whether participation in these networks or other surveillance was associated with vaccine introduction.

METHODS

Between 2006 and 2018, among all WHO member states, we used multivariable models adjusting for economic status to assess (1) the association between surveillance for pneumococcal disease or rotavirus disease, including participation in GISN or GRSN and the introduction of the PCV or the rotavirus vaccine, respectively, and (2) the association between the rotavirus disease burden and the rotavirus vaccine introduction among 56 countries participating in GRSN from 2008 to 2018.

RESULTS

Countries that participated in or conducted surveillance for invasive pneumococcal disease or rotavirus disease were 3.5 (95% confidence interval [CI], 1.7-7.1) and 4.2 (95% CI, 2.1-8.6) times more likely to introduce PCV or rotavirus respectively, compared to those without surveillance. Among countries participating in GRSN, there was insufficient evidence to demonstrate an association between countries with higher rotavirus positivity and vaccine introduction.

CONCLUSIONS

Surveillance should be incorporated into advocacy strategies to encourage the introduction of vaccines, with countries benefiting from data from, support for, and coordination of international disease surveillance networks.

A fuzzy multi-criteria framework to identify barriers and enablers of the next-generation vaccine supply chain

Purpose

Due to the introduction of new vaccines in the child immunization program and inefficient vaccine supply chain (VSC), the universal immunization program (UIP), India is struggling to provide a full schedule of vaccination to the targeted children. In this paper, the authors investigate the critical factors for improving the performance of the existing VSC system by implementing the next-generation vaccine supply chain (NGVSC) in India.

Design/methodology/approach

The authors design a fuzzy multi-criteria framework using a fuzzy analytical hierarchical process (FAHP) and fuzzy multi-objective optimization on the basis of ratio analysis (FMOORA) to identify and analyze the critical barriers and enablers for the implementation of NGVSC. Further, the authors carry out a numerical simulation to validate the model.

Findings

The outcome of the analysis contends that demand forecasting is the topmost supply chain barrier and sustainable financing is the most important/critical enabler to facilitate the implementation of the NGVSC. In addition, the simulation reveals that the results of the study are reliable.

Social implications

The findings of the study can be useful for the child immunization policymakers of India and other developing countries to design appropriate strategies for improving existing VSC performance by implementing the NGVSC.

Originality/value

To the best of the authors’ knowledge, the study is the first empirical study to propose the improvement of VSC performance by designing the NGVSC.

New Vaccine Introduction and Childhood Vaccination Timeliness in Two Urban, Informal Settlements in Nairobi, Kenya

New vaccine introduction accompanied by social mobilization activities could contribute to improved routine immunization timeliness. This study assesses the impact of Kenya's introduction of pneumococcal conjugate vaccine (PCV) on the timeliness of routine childhood vaccination in two informal, urban settlements in Nairobi. Data collected from 2007 to 2015 as part of a demographic surveillance system were used to estimate annual vaccination delays of ≥ 4 weeks among children aged 12-23 months in the period before and after the introduction of PCV in Kenya. Binomial segmented regression models using generalized estimating equations examined the association between vaccine introduction and timeliness of routine immunization. Over half of all children vaccinated in the two urban areas received one or more doses ≥ 4 weeks after the recommended age. The timeliness of routine immunization showed slight improvements or nonsignificant changes during the years following PCV introduction compared with the preceding years (adjusted prevalence ratio [aPR]: 0.67, 95% CI: 0.45-0.99 for Bacille Calmette-Guerin receipt; aPR: 0.59, 95% CI: 0.41-0.83 for third dose Pentavalent receipt; aPR: 1.19, 95% CI: 0.99-1.42 for measles). However, as of 2015, delayed vaccination remained prevalent in children, particularly among the poorest residing in the settlements. Many sub-Saharan African countries have introduced new life-saving vaccines into their routine childhood immunization schedule. Additional evidence regarding the positive or neutral influence of new vaccine introduction on the performance of delivery systems provides further justification to sustain the inclusion of these more costly vaccines in the immunization schedule.

Redesigning immunization supply chains: Results from three country analyses

INTRODUCTION

Immunization supply chains (iSC) are essential for ensuring access to vaccines that prevent diseases. Guinea, Madagascar, and Niger initiated iSC system design efforts to conduct analysis of alternative supply chain scenarios to identify areas for improvement.

METHODOLOGY

Key stakeholders from Ministries of Health and immunization programs identified bottlenecks in the current iSC and prioritized five general design scenarios to model in each country. Scenarios included aspects of integration, changing supply chain levels and delivery frequency, ignoring administrative boundaries, and direct delivery. Primary and secondary data were collected and cleaned. Analysis was completed using Supply Chain Guru (Madagascar and Niger) and AnyLogistix (Guinea) modeling software to build a virtual representation of the iSC physical components and operating policies.

RESULTS

Modeling results were compared using both quantitative and qualitative criteria (total operating costs, cost per dose, cold chain capacity, risk of mishandling, logistics burden on healthcare workers, feasibility to implement, and equity). Using a Stop Light Analysis for user-friendly understanding of positive, negative or minimal impact on scenarios, cost savings were realized in most scenarios in Madagascar (except using autonomous aerial vehicles); proposed scenarios in Guinea increased costs or had minimal impact; in Niger, eliminating regional tiers reduced costs. Facility level cold chain was sufficient in all countries. Effect on qualitative indicators largely depended on the scenario and country context.

DISCUSSION

Similarities in scenarios selected were seen across the three countries. Results suggest that efficiencies can be found through changes to the iSC design, but the benefits of each scenario must be considered in the country context. Results of the analysis do not provide "the right answer" but rather options and guidance which then must be grounded in the country context and used as evidence for decision making to ensure reliable availability of vaccines.

Efficacy and Safety of a 3-Antigen (Pre-S1/Pre-S2/S) Hepatitis B Vaccine: Results of a Phase 3 randomized clinical trial in the Russian Federation

Background

This study compares the immunogenicity and safety of a 3-antigen (S/pre-S1/pre-S2) hepatitis B (HepB) vaccine (3AV), to a single antigen vaccine (1AV) in adults to support the registration of 3AV in Russia.

Methods

We conducted a randomized, double-blind, comparative study of 3-dose regimens of 3AV (10 μg) and 1AV (20 µg) in adults aged 18–45 years. We evaluated immunogenicity based on hepatitis B surface (HBs) antibody titers at days 1, 28, 90, 180, and 210, adverse and serious adverse events (SAEs) to study day 210. The primary outcome was based on the difference in rates of seroconversion at day 210 (lower bound 95% confidence interval [CI]: > − 4%). Secondary outcomes were seroprotection rates (SPR), defined as anti-HBs ≥10 mIU/mL and anti-HBs geometric mean concentration (GMC).

Results

Rate of seroconversion in 3AV (100%) was noninferior to 1AV (97.9%) at study day 210 (difference: 2.1%, 95% CI: −2.0, 6.3%]) but significantly higher at study day 28. SPR at study day 210 was >97% in both arms. Anti-HBs titers were significantly higher at study days 90 (P = .001) and 180 (P = .0001) with 3AV. Sex, age, and body mass index (BMI) had no impact on anti-HBs titers. The rates of local reactions related to vaccination were similar between vaccine arms (3AV vs 1AV) after the first (30% vs 18.8%, P = .15), second (20.0% vs 14.6%, P = .33), and third vaccination (14.9% vs 23.4%, P = .22). No SAEs were reported.

Conclusions

3AV was noninferior to 1AV. 3AV induced high SPR, and there were no safety concerns.

Clinical Trials Registration. NCT04209400.

Prevalence of Rotavirus-Associated Acute Gastroenteritis Cases in Early Childhood in Turkey: Meta-Analysis

BACKGROUND

Rotavirus is globally the most common viral pathogen in childhood gastroenteritis. This study aimed to estimate the number of Turkish children suffering from early-childhood gastroenteritis by rotavirus by performing a meta-analysis.

METHODS

Meta-analysis following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was performed. Following the guidelines, primary studies were found reporting the prevalence of rotavirus gastroenteritis in Turkey. We performed a computerized search of published studies in national and international databases from 1990 to 2018. We selected 38 out of 721 studies for our study. Meta-analysis was carried out using R statistical software. The Cochrane Q statistic was calculated to assess the heterogeneity of the study results. Heterogeneity among studies was evaluated using the I² statistic. Effect-size estimate was reported with 95% confidence interval.

RESULTS

On the basis of 38 selected articles, 80,113 children up to five years of age were diagnosed with symptoms of acute gastroenteritis, of whom the stool samples of 13,651 children were positive for rotavirus. The pooled prevalence of rotavirus was 19% in children younger than five years of age with acute gastroenteritis. In terms of seasonal prevalence, the highest prevalence rate was found in winter.

CONCLUSION

This study supports the major prevalence of early-childhood gastroenteritis by rotavirus among Turkish children. Therefore, the decision to adopt immunization programs to prevent rotavirus infection might be helpful in Turkey.

Etiology of Bacterial Meningitis Among Children <5 Years Old in Côte d'Ivoire: Findings of Hospital-based Surveillance Before and After Pneumococcal Conjugate Vaccine Introduction

Background

Bacterial meningitis remains a major disease affecting children in Côte d’Ivoire. Thus, with support from the World Health Organization (WHO), Côte d’Ivoire has implemented pediatric bacterial meningitis (PBM) surveillance at 2 sentinel hospitals in Abidjan, targeting the main causes of PBM: Streptococcus pneumoniae (pneumococcus), Haemophilus influenzae, and Neisseria meningitidis (meningococcus). Herein we describe the epidemiological characteristics of PBM observed in Côte d’Ivoire during 2010–2016.

Methods

Cerebrospinal fluid (CSF) was collected from children aged <5 years admitted to the Abobo General Hospital or University Hospital Center Yopougon with suspected meningitis. Microbiology and polymerase chain reaction (PCR) techniques were used to detect the presence of pathogens in CSF. Where possible, serotyping/grouping was performed to determine the specific causative agents.

Results

Overall, 2762 cases of suspected meningitis were reported, with CSF from 39.2% (1083/2762) of patients analyzed at the WHO regional reference laboratory in The Gambia. In total, 82 (3.0% [82/2762]) CSF samples were positive for bacterial meningitis. Pneumococcus was the main pathogen responsible for PBM, accounting for 69.5% (52/82) of positive cases. Pneumococcal conjugate vaccine serotypes 5, 18C, 19F, and 6A/B were identified post–vaccine introduction. Emergence of H. influenzae nontypeable meningitis was observed after H. influenzae type b vaccine introduction.

Conclusions

Despite widespread use and high coverage of conjugate vaccines, pneumococcal vaccine serotypes and H. influenzae type b remain associated with bacterial meningitis among children aged <5 years in Côte d’Ivoire. This reinforces the need for enhanced surveillance for vaccine-preventable diseases to determine the prevalence of bacterial meningitis and vaccine impact across the country.

A systematic review of the agreement of recall, home-based records, facility records, BCG scar, and serology for ascertaining vaccination status in low and middle-income countries

Background: Household survey data are frequently used to estimate vaccination coverage - a key indicator for monitoring and guiding immunization programs - in low and middle-income countries. Surveys typically rely on documented evidence from home-based records (HBR) and/or maternal recall to determine a child's vaccination history, and may also include health facility sources, BCG scars, and/or serological data. However, there is no gold standard source for vaccination history and the accuracy of existing sources has been called into question. Methods and Findings: We conducted a systematic review of literature published January 1, 1975 through December 11, 2017 that compared vaccination status at the child-level from at least two sources of vaccination history. 27 articles met inclusion criteria. The percentage point difference in coverage estimates varied substantially when comparing caregiver recall to HBRs (median: +1, range: -43 to +17), to health facility records (median: +5, range: -29 to +34) and to serology (median: -20, range: -32 to +2). Ranges were also wide comparing HBRs to facility-based records (median: +17, range: -61 to +21) and to serology (median: +2, range: -38 to +36). Across 10 studies comparing recall to HBRs, Kappa values exceeded 0.60 in 45% of comparisons; across 7 studies comparing recall to facility-based records, Kappa never reached 0.60. Agreement varied depending on study setting, coverage level, antigen type, number of doses, and child age. Conclusions: Recall and HBR provide relatively concordant vaccination histories in some settings, but both have poor agreement with facility-based records and serology. Long-term, improving clinical decision making and vaccination coverage estimates will depend on strengthening administrative systems and record keeping practices. Short-term, there must be greater recognition of imperfections across available vaccination history sources and explicit clarity regarding survey goals and the level of precision, potential biases, and associated resources needed to achieve these goals.

A systematic review of the agreement of recall, home-based records, facility records, BCG scar, and serology for ascertaining vaccination status in low and middle-income countries

Background: Household survey data are frequently used to estimate vaccination coverage - a key indicator for monitoring and guiding immunization programs - in low and middle-income countries. Surveys typically rely on documented evidence from home-based records (HBR) and/or maternal recall to determine a child’s vaccination history, and may also include health facility sources, BCG scars, and/or serological data. However, there is no gold standard source for vaccination history and the accuracy of existing sources has been called into question.

Methods and Findings: We conducted a systematic review of literature published January 1, 1975 through December 11, 2017 that compared vaccination status at the child-level from at least two sources of vaccination history. 27 articles met inclusion criteria. The percentage point difference in coverage estimates varied substantially when comparing caregiver recall to HBRs (median: +1, range: -43 to +17), to health facility records (median: +5, range: -29 to +34) and to serology (median: -20, range: -32 to +2). Ranges were also wide comparing HBRs to facility-based records (median: +17, range: -61 to +21) and to serology (median: +2, range: -38 to +36). Across 10 studies comparing recall to HBRs, Kappa values exceeded 0.60 in 45% of comparisons; across 7 studies comparing recall to facility-based records, Kappa never reached 0.60. Agreement varied depending on study setting, coverage level, antigen type, number of doses, and child age.

Conclusions: Recall and HBR provide relatively concordant vaccination histories in some settings, but both have poor agreement with facility-based records and serology. Long-term, improving clinical decision making and vaccination coverage estimates will depend on strengthening administrative systems and record keeping practices. Short-term, there must be greater recognition of imperfections across available vaccination history sources and explicit clarity regarding survey goals and the level of precision, potential biases, and associated resources needed to achieve these goals.

School-based delivery of routinely recommended vaccines and opportunities to check vaccination status at school, a global summary, 2008-2017

School-based vaccination (SBV) and checking students' vaccination records at school have the potential to optimize vaccination coverage among school-aged children. The primary aim of this paper is to describe adoption of SBV by countries from 2008 to 2017, including target age groups and vaccines delivered in 2017, as reported annually through the World Health Organization (WHO)-United Nations Children's fund (UNICEF) Joint Reporting Form (JRF). Expanding upon previous analyses, country-specific rates of primary school enrollment and home-based record (HBR) ownership were linked to the WHO-UNICEF JRF data, to identify countries with high potential to implement vaccination record checks at school. The proportion of countries reporting delivery of at least one routinely recommended vaccine dose in school settings increased from 95 (of 163 reporting; 58%) in 2008 to 108 (of 181 reporting; 60%) in 2017. The 13 additional countries that reported using SBV in 2017 were among 31 countries for which SBV data from the JRF were unavailable in 2017. The most common antigens delivered through SBV in 2017 were tetanus (94 countries), diphtheria (89 countries), and human papillomavirus (52 countries). Among 93 countries with data available for net primary school enrollment and HBR ownership, 52 (56%) countries had both ≥80% net primary school enrollment and ≥80% of children aged 12-23 months ever owning an HBR; 33 (63%) of these used SBV. If not already doing so, these 33 countries represent an opportunity to introduce routine checking of vaccination status at entry to, or during primary school. With the growing number of new vaccines and booster doses of childhood vaccines targeting school-age children, implementation of SBV and checking of student vaccination records at school may help improve vaccination coverage; however, additional data are needed to assess global prevalence of checking vaccination status at school and to identify factors facilitating optimal implementation of this strategy.

New immunization strategies: adapting to global challenges

Immunization has made an enormous contribution to global health. Global vaccination coverage has dramatically improved and mortality rates among children due to vaccine-preventable diseases have been significantly reduced since the creation of the Expanded Programme of Immunization in 1974, the formation of Gavi, the Vaccine Alliance, in 2000, and the development of the Global Vaccine Action Plan in 2012. However, challenges remain and persisting inequities in vaccine uptake contribute to the continued occurrence and outbreaks of vaccine-preventable diseases. Inequalities in immunization coverage by geography, urban-rural, and socio-economic status jeopardize the achievement of global immunization goals and call for renewed immunization strategies. These should take into account emerging opportunities for building better immunization systems and services, as well as the development of new vaccine products and delivery technologies. Such strategies need to achieve equity in vaccination coverage across and within countries. This will require the participation of communities, a better understanding of vaccine acceptance and hesitancy, the expansion of vaccination across the life course, approaches to improve immunization in middle-income countries, enhanced use of data and possible financial and non-financial incentives. Vaccines also have an important role to play in comprehensive disease control, including the fight against antimicrobial resistance. Lessons learned from disease eradication and elimination efforts of polio, measles and maternal and neonatal tetanus are instrumental in further enhancing global immunization strategies in line with the revised goals and targets of the new Immunization Agenda 2030, which is currently being developed.

Pneumococcal pneumonia and carriage in Africa before and after introduction of pneumococcal conjugate vaccines, 2000-2019: protocol for systematic review

INTRODUCTION

Africa harbours a high burden of pneumococcal disease, with associated high mortality rates. Despite 34 countries introducing the pneumococcal conjugate vaccine, which reduces the risk of pneumococcal carriage (a prerequisite for disease) of some of the most pathogenic pneumococcal serotypes, it remains uncertain whether they will achieve the sustained direct or indirect protection necessary to reduce pneumococcal carriage to levels sufficient to interrupt transmission and disease. We will therefore summarise the available data on the impact of the pneumococcal conjugate vaccine in reducing vaccine serotype carriage and pneumococcal pneumonia in Africa between 2000 and 2019.

METHODS AND ANALYSIS

Using a predetermined search strategy, we will conduct a comprehensive search of PubMed, MEDLINE database, the Excerpta Medica Database, the ISI Web of Science (Science Citation Index), Scopus and the African Index Medicus to identify published studies reporting the prevalence of Streptococcus pneumoniae carriage (vaccine type and non-vaccine type), incidence rates of pneumococcal pneumonia and mortality among children, adults and HIV-infected (all-ages) pre-pneumococcal conjugate vaccine (PCV) and post-PCV introduction (published between 1st January 2000 and 31st December 2019) in African countries that have introduced PCVs (PCV7/PCV10/PCV13) in their routine national immunisation programme. The studies retained and data extracted will be assessed for bias using prevalidated tools and checklists. Heterogeneity across studies will be assessed using the χ2 test on Cochrane Q statistic. A random effect meta-analysis will be used to estimate the overall prevalence of pneumococcal carriage and incidence of pneumococcal pneumonia across studies with similar characteristics. Results will be reported in compliance with the Meta-Analysis Of Observational Studies in Epidemiology guidelines. The protocol has been prepared in accordance to the 2015 guidelines on Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

ETHICS AND DISSEMINATION

This systematic review will not require ethical approval as we will be using already published data. The final manuscript will be submitted for publication in a peer-reviewed journal and presented at conferences.

PROSPERO REGISTRATION NUMBER

CRD42019130976.

New vaccine introductions in Africa before and during the decade of vaccines - Are we making progress?

Vaccines are excellent investments with far-reaching rewards beyond individual and population health, but their introduction into national programs has been historically slow in Africa. We provide an overview of the introduction of new and underutilized vaccines in countries of the WHO African Region by 2017, using data from the WHO-UNICEF Joint Reporting Form. By 2017, all 47 countries had introduced vaccines containing hepatitis B (compared to 11% in 2000 and 98% in 2010) and Haemophilus influenzae type b (Hib) (compared to 4% in 2000 and 91% in 2010). The proportion of countries that had introduced other vaccines by 2017 was 83% for pneumococcal conjugate vaccine (PCV) from 7% in 2010, 72% for rotavirus vaccine from 2% in 2010, 55% for the second dose of a measles-containing vaccine (MCV2) (compared to 11% in 2000 and 17% in 2010), and 45% for rubella-containing vaccines (RCV) (compared to 4% in 2000 and 7% in 2010). From 2000 to 2010, there was no significant difference between countries eligible (N = 36) and those not eligible (N = 10) for Gavi support in the introduction of hepatitis B and PCV. However, Gavi eligible countries were more likely to introduce Hib and non-Gavi eligible countries were more likely to introduce MCV2 and RCV. From 2010 to 2017, the only significant differences that remained between the two groups of countries were with mumps, inactivated polio and seasonal influenza vaccines; which non-Gavi eligible countries were more likely to have introduced. There has been significant progress in the introduction of new childhood vaccines in Africa, mostly driven by Gavi support. As many countries are expected to transition out of Gavi support soon, there is need for countries in the region to identify predictable, reliable and sustainable immunization funding mechanisms. This requires commitments and actions that go beyond the purchase of vaccines.

Introducing new vaccines in low- and middle-income countries: challenges and approaches

INTRODUCTION

The number of new vaccine introductions (NVIs) in low and middle-income countries (LMICs) has markedly increased since 2010, raising challenges to often overstretched and underfunded health care systems.

AREAS COVERED

We present an overview of some of these challenges, focusing on programmatic decisions, delivery strategy, information and communication, pharmacovigilance and post-licensure evaluation. We also highlight field-based initiatives that may facilitate NVI.

EXPERT COMMENTARY

Some new vaccines targeting populations other than infants require alternative delivery strategies. NVIs impact upon existing supply chain management, in particular vaccines with novel characteristics. A lack of understanding about immunization and misconceptions may be detrimental to NVI, as well as insufficient or poorly trained health care workforce. Many barriers exist to achieving good vaccination coverage. Real-world evaluation of vaccine safety, effectiveness and impact in LMICs may be limited by lack of robust demographic and disease epidemiology data, as well as limited health care and surveillance infrastructure. A thorough planning phase is crucial to define the most suitable delivery strategy based on the vaccine's and country's specificities. A communication plan and social mobilization are essential. Implementation research and innovative approaches applied to logistics, delivery, communication and program evaluation can facilitate NVI.

Rotavirus infections in children in Turkey: A systematic review

We aimed to describe rotavirus epidemiology and clinical findings including extraintestinal manifestations in a setting that has yet to introduce rotavirus vaccines in the national immunization program. A literature search was performed by using the key words "Turkey" and "rotavirus." Ninety-eight studies published between 1987 and 2016 including epidemiological, clinical, and genotypical data at least 1 year duration were included. There were a total of 117 741 children with diarrhea and 26 566 rotavirus gastroenteritis with a median detection rate 31.8% (95% CI, 31.3-32.4) under 5 years of age. The rate of dehydration was 47% (95% CI, 23.4-91.6). There were 328 cases reported to be presenting with a various complication related to rotavirus in 2750 children in eight studies. The overall complication rate was 11.7% (95% CI, 10.7-12.9). The cumulative incidence of the most common genotypical combinations circulating worldwide was only 59.7% (G9[P8], 25%; G1[P8], 22%; G2[P4], 5.6%; G3[P8], 2.6%; G4[P8], 4.5%) whereas mixed, untypeable, and other genotypes were 2.4%, 15%, and 22.9% respectively. Our results point out the importance of rotavirus vaccination by presenting that rotavirus may cause severe complications besides severe gastroenteritis. The role of strain diversity in the variability of clinical presentations of rotavirus infections needs to be further investigated.

Strengthening Care Delivery in Primary Care Facilities: Perspectives of Facility Managers on the Immunization Program in Kenya

BACKGROUND

Primary healthcare facility managers (PHFMs) occupy a unique position in the primary healthcare system, as the only cadre combining frontline clinical activities with managerial responsibilities. Often serving as 'street-level bureaucrats,' their perspectives can provide contextually relevant information about interventions for strengthening primary healthcare delivery, yet such perspectives are under-represented in the literature on primary healthcare strengthening. Our objective in this study was to explore perspectives of PHFMs in western Kenya regarding how to leverage human resource factors to improve immunization programs, in order to draw lessons for strengthening of primary healthcare delivery.

METHODS

We employed a sequential mixed methods approach. We conducted in-depth interviews with key informants in Kakamega County. Emergent themes guided questionnaire development for a cross-sectional survey. We randomly selected 94 facility managers for the survey which included questions about workload, effects of workload on immunization program, and appropriate measures to address workload effects. Participants provided self-assessment of their general motivation at work, their specific motivation to ensure that all children in their catchment areas were fully immunized, and recommendations to improve motivation. Participants were asked about frequency of supervisory visits, supervisor activities during those visits, and how to improve supervision.

RESULTS

The most frequently reported consequences of high workload were reduced accuracy of vaccination records (47%) and poor client counseling (47%). Hiring more clinical staff was identified as an effective remedy to high workload (69%). Few respondents (20%) felt highly motivated to ensure full immunization coverage and only 13% reported being very motivated to execute their role as a health worker generally. Increasing frequency of supervisory visits and acting on the feedback received during those visits were mostly perceived as important measures to improve program effectiveness.

CONCLUSION

Besides increasing the number of staff providing clinical care, PHFMs endorsed introducing some financial incentives contingent on specified targets and making supervisory visits meaningful with action on feedback as strategies to increase program effectiveness in primary healthcare facilities in Kenya. Targeting health worker motivation and promoting supportive supervision may reduce missed opportunities and poor client counseling in primary healthcare facilities in Kenya.

Incidence and aetiology of bacterial meningitis among children aged 1-59 months in South Asia: systematic review and meta-analysis

BACKGROUND

Bacterial meningitis is a significant cause of morbidity and mortality worldwide among children aged 1-59 months. We aimed to describe its burden in South Asia, focusing on vaccine-preventable aetiologies.

METHODS

We searched five databases for studies published from January 1, 1990, to April 25, 2017. We estimated incidence and aetiology-specific proportions using random-effects meta-analysis. In secondary analyses, we described vaccine impact and pneumococcal meningitis serotypes.

RESULTS

We included 48 articles cumulatively reporting 20,707 cases from 1987 to 2013. Mean annual incidence was 105 (95% confidence interval [CI], 53-173) cases per 100,000 children. On average, Haemophilus influenzae type b (Hib) accounted for 13% (95% CI, 8-19%) of cases, pneumococcus for 10% (95% CI, 6-15%), and meningococcus for 1% (95% CI, 0-2%). These meta-analyses had substantial between-study heterogeneity (I² > 78%, P < 0.0001). Among studies reporting only confirmed cases, these three bacteria caused a median of 78% cases (IQR, 50-87%). Hib meningitis incidence declined by 72-83% at sentinel hospitals in Pakistan and Bangladesh, respectively, within two years of implementing nationwide vaccination. On average, PCV10 covered 49% (95% CI, 39-58%), PCV13 covered 51% (95% CI, 40-61%), and PPSV23 covered 74% (95% CI, 67-80%) of pneumococcal meningitis serotypes. Lower PCV10 and PCV13 serotype coverage in Bangladesh was associated with higher prevalence of serotype 2, compared to India and Pakistan.

CONCLUSIONS

South Asia has relatively high incidence of bacterial meningitis among children aged 1-59 months, with vaccine-preventable bacteria causing a substantial proportion. These estimates are likely underestimates due to multiple epidemiological and microbiological factors. Further research on vaccine impact and distribution of pneumococcal serotypes will inform vaccine policymaking and implementation.

Rotavirus Vaccines: Effectiveness, Safety, and Future Directions

Rotavirus is the leading cause of diarrheal death among children < 5 years old worldwide, estimated to have caused ~ 215,000 deaths in 2013. Prior to rotavirus vaccine implementation, > 65% of children had at least one rotavirus diarrhea illness by 5 years of age and rotavirus accounted for > 40% of all-cause diarrhea hospitalizations globally. Two live, oral rotavirus vaccines have been implemented nationally in > 100 countries since 2006 and their use has substantially reduced the burden of severe diarrheal illness in all settings. Vaccine efficacy and effectiveness estimates suggest there is a gradient in vaccine performance between low child-mortality countries (> 90%) and medium and high child-mortality countries (57-75%). Additionally, an increased risk of intussusception (~ 1-6 per 100,000 vaccinated infants) following vaccination has been documented in some countries, but this is outweighed by the large benefits of vaccination. Two additional live, oral rotavirus vaccines were recently licensed and these have improved on some programmatic limitations of earlier vaccines, such as heat stability, cost, and cold-chain footprint. Non-replicating rotavirus vaccines that are parenterally administered are in clinical testing, and these have the potential to reduce the performance differential and safety concerns associated with live oral rotavirus vaccines.

Geospatial Planning and the Resulting Economic Impact of Human Papillomavirus Vaccine Introduction in Mozambique

BACKGROUND

Research has shown that the distance to the nearest immunization location can ultimately prevent someone from getting immunized. With the introduction of human papillomavirus (HPV) vaccine throughout the world, a major question is whether the target populations can readily access immunization.

METHODS

In anticipation of HPV vaccine introduction in Mozambique, a country with a 2015 population of 25,727,911, our team developed Strategic Integrated Geo-temporal Mapping Application) to determine the potential economic impact of HPV immunization. We quantified how many people in the target population are reachable by the 1377 existing immunization locations, how many cannot access these locations, and the potential costs and disease burden averted by immunization.

RESULTS

If the entire 2015 cohort of 10-year-old girls goes without HPV immunization, approximately 125 (111-139) new cases of HPV 16,18-related cervical cancer are expected in the future. If each health center covers a catchment area with a 5-km radius (ie, if people travel up to 5 km to obtain vaccines), then 40% of the target population could be reached to prevent 50 (44-55) cases, 178 (159-198) disability-adjusted life years, and US $202,854 (US $140,758-323,693) in health care costs and lost productivity. At higher catchment area radii, additional increases in catchment area radius raise population coverage with diminishing returns.

CONCLUSIONS

Much of the population in Mozambique is unable to reach any existing immunization location, thereby reducing the potential impact of HPV vaccine. The geospatial information system analysis can assist in planning vaccine introduction strategies to maximize access and help the population reap the maximum benefits from an immunization program.

Decline of rotavirus-coded hospitalizations in children under 5 years: A report from Japan where rotavirus vaccines are self-financed

OBJECTIVES

To estimate the trend in incidence of rotavirus gastroenteritis (RVGE) hospitalization among children aged <5 years in Japan during pre- and post-vaccine periods (2009-2011 and 2012-2015).

STUDY DESIGN

This retrospective observational study used a health insurance claims database (constructed by Japan Medical Data Center Co., Ltd.). Rotavirus vaccine became commercially available in 2011. We analyzed data of all children aged <5 years between January 2009 and December 2015. We estimated the incidence rate (IR) of RVGE hospitalization per 1000 person-years from 2009 to 2015 and incidence rate ratio (IRR) of post-vaccine years compared with the averaged pre-vaccine years. IRs and IRRs were also estimated by age group. Primary analysis was limited to the rotavirus season (January to June) of each year.

RESULTS

The IR was 6.3-9.3 in pre-vaccine years, 2.3 in 2014, and 3.0 in 2015; the decline was estimated to be 71% in 2014 and 61% in 2015 (p<0.01). By age group, reduction in hospitalizations began in 2013 among children <1 year old, followed by children aged 1 to <5 years in 2014. In the 2014 season, a 65% reduction in RVGE hospitalization was observed in children aged 36 to <60 months, although this age group was unlikely to be vaccinated.

CONCLUSIONS

A substantial decline of RVGE hospitalization in 2014 and its persistence was observed among children aged <5 years in Japan after introduction of rotavirus vaccine, although not included in the national immunization program. Indirect effects of rotavirus vaccination were suggested in the 2014 season.

Prevention of human papillomavirus (HPV)-related tumors in people living with human immunodeficiency virus (HIV)

INTRODUCTION

In comparison to their HIV-negative counterparts, people living with HIV (PLWH) have a higher prevalence of human papillomavirus (HPV) infection in various anatomical sites coupled with increased HPV persistence, higher risk of HPV-related tumors, and faster disease progression. Areas covered: Gender-neutral prevention strategies for HPV-related cancers in PLWH discussed: ABC approach, HPV vaccination, antiretroviral treatment (ART), anal cancer screening, and smoking cessation. Gender specific strategies: cervical cancer screening reduces the incidence and mortality of cervical cancer and circumcision might reduce the risk of HPV infections in men. Expert commentary: HPV-related cancer incidence has not declined (e.g. cervical cancer) and has even increased (e.g. anal cancer) in the ART era, demanding an effective HPV prevention strategy. HPV vaccination should be introduced into national prevention programs worldwide immediately because current prophylactic vaccines are safe, tolerable, and immunogenic in PLWH. HPV vaccine efficacy trials in PLWH are essential to determine the most appropriate immunization schedule. The population most at risk of anal cancer is HIV-positive men who have sex with men, who are not protected by herd immunity if only the female population is vaccinated. Unvaccinated PLWH need enhanced surveillance for early detection of HPV-related cancers and their precursors.

Rubella virus infection and associated factors among pregnant women attending the antenatal care clinics of public hospitals in Hawassa City, Southern Ethiopia: a cross-sectional study

OBJECTIVE

To assess the seroprevalence of recent/acute and past exposure to rubella virus infection and associated risk factors among pregnant women.

DESIGN

A hospital-based cross-sectional study.

SETTING

The study was conducted in two public hospitals in Hawassa City, Southern Ethiopia.

PARTICIPANTS

A total of 422 pregnant women attending antenatal care clinics were selected using a systematic random sampling technique from March to June 2016.

OUTCOME MEASURES

Data on sociodemography and related factors were collected using a structured questionnaire. Blood samples were also collected from each study participant and tested for antirubella IgM and IgG antibodies using ELISA. IgG seropositivity indicates past exposure to rubella (protective immunity). IgM seropositivity indicates recent exposure to rubella (or reinfection).

RESULTS

The seroprevalence of antirubella IgM and IgG antibodies was 2.1% and 86.3%, respectively. Thus, the rate of susceptibility to rubella virus infection among pregnant women was found to be 13.7%. A significant association between residence site and IgG seropositivity was observed, where urban dwellers had higher past rubella exposure compared with rural residents (crude OR 6.3; 95% CI 3.29 to 12.14, p<0.001).

CONCLUSION

The high rate of rubella exposure and its similar distribution by sociodemography (except residence site) suggests the continuous transmission and endemicity of the infection in the study area. These findings emphasise the importance of introducing rubella-containing vaccine into routine childhood immunisation programme and vaccinating susceptible women of childbearing age.

Identification of vaccine-derived rotavirus strains in children with acute gastroenteritis in Japan, 2012-2015

Two live attenuated oral rotavirus vaccines, Rotarix and RotaTeq, have been introduced as voluntary vaccination in Japan since 2011 and 2012, respectively. Effectiveness of the vaccines has been confirmed, whereas concerns such as shedding of the vaccine strains and gastroenteritis cases caused by vaccine strains are not well assessed. We aimed to identify the vaccine strains in children with acute gastroenteritis (AGE) to investigate the prevalence of AGE caused by vaccination or horizontal transmission of vaccine strains. A total of 1,824 stool samples were collected from children with AGE at six outpatient clinics in 2012-2015. Among all, 372 group A rotavirus (RVA) positive samples were screened for vaccine components by real-time RT-PCR which were designed to differentiate vaccine strains from rotavirus wild-type strains with high specificity. For samples possessing both vaccine and wild-type strains, analyses by next-generation sequencing (NGS) were conducted to characterize viruses existed in the intestine. As a result, Rotarix-derived strains were identified in 6 of 372 (1.6%) RVA positive samples whereas no RotaTeq strain was detected. Among six samples, four possessed Rotarix-derived strains while two possessed both Rotarix-derived strains and wild-type strains. In addition, other pathogens such as norovirus, enterovirus and E.coli were detected in four samples. The contribution of these vaccine strains to each patient's symptoms was unclear as all of the cases were vaccinated 2-14 days before sample collection. Proportion of average coverage for each segmented gene by NGS strongly suggested the concurrent infection of the vaccine-derived strain and the wild-type strain rather than reassortment of these two strains in one sample. This is the first study to report the prevalence of vaccine-derived strains in patients with RVA AGE in Japan as 1.6% without evidence of horizontal transmission. The results emphasized the importance of continuous monitoring on vaccine strains and their clinical impacts on children.

Hospitalisation for lower respiratory tract infection in children in the province of Quebec, Canada, before and during the pneumococcal conjugate vaccine era

Streptococcus pneumoniae is an important cause of community-acquired pneumonia and pneumococcal conjugate vaccines (PCVs) may reduce this burden. This study's goal was to analyse trends in lower respiratory tract infections (LRTI) hospitalisations before and during a routine vaccination programme targeting all newborns with PCV was started in the province of Quebec, Canada in December 2004. The study population included hospital admissions with a main diagnosis of LRTI among 6-59 month-old Quebec residents from April 2000 to December 2014. Trends in proportions and rates were analysed using Cochran-Armitage tests and Poisson regression models. We observed a general downward trend in all LTRI hospitalisations rate: from 11·55/1000 person-years in 2000-2001 to 9·59/1000 in 2013-2014, a 17·0% reduction, which started before the introduction of PCV vaccination. Downward trends in hospitalisation rates were more pronounced for all-cause of pneumonia (minus 17·8%) than for bronchiolitis (minus 15·4%). There was also a decrease in the mean duration of hospital stay. There was little evidence that all-cause pneumonia decreased over the study period due mainly to the introduction of PCVs. Trends may be related to changes in clinical practice. This study casts doubt on the interpretation of ecological analyses of the implementation of PCV vaccination programmes.

Rapid replacement by non-vaccine pneumococcal serotypes may mitigate the impact of the pneumococcal conjugate vaccine on nasopharyngeal bacterial ecology

There is growing concern that interventions that alter microbial ecology can adversely affect health. We characterised the impact of the seven-valent pneumococcal conjugate vaccine (PCV7) on pneumococcal carriage and the bacterial component of the nasopharyngeal microbiome during infancy. Newborns were recruited into three groups as follows: Group1 (n = 33) was the control group and comprised infants who received PCV7 after 6 months and came from unvaccinated communities. Group 2 (n = 30) came from unvaccinated communities and Group 3 (n = 39) came from vaccinated communities. Both group 2 and 3 received PCV7 at 2, 3 and 4 months. Culture and 16 S rRNA gene sequencing were performed on nasopharyngeal specimens collected at regular intervals from infants. Nasopharyngeal carriage of PCV7 serotypes in Group 1 was significantly higher than in Group 2 and 3 (p < 0.01). However, pneumococcal carriage remained comparable due to an expansion of non-vaccine serotypes in Groups 2 and 3. Determination of phylogenetic dis(similarities) showed that the bacterial community structures were comparable across groups. A mixed effects model showed no difference in community richness (p = 0.15) and Shannon α-diversity (p = 0.48) across the groups. Immediate replacement of pneumococcal vaccine serotypes with non-vaccine serotypes may mitigate the impact of PCV7 on nasopharyngeal bacterial community structure and ecology.

Progress in prophylactic human papillomavirus (HPV) vaccination in 2016: A literature review

Prophylactic human papillomavirus (HPV) vaccine represents a revolutionary step forward in preventing HPV-related cancers, especially cervical carcinoma. Alongside appropriate screening, it has the potential to dramatically reduce cervical cancer incidence and even eradicate it. Following extensive evaluations in clinical trials, the first decade of routine HPV vaccine use provides overwhelming evidence of the vaccines' safety and their real-life effectiveness. In 2016, further clinical trials showed high vaccine efficacy in adult women, especially those that were HPV DNA-negative at baseline, and indicated possible protection from HPV-related diseases after treatment of precancerous cervical lesions. The recommendation for a two-dose schedule in individuals under 15 is further supported for all three licensed vaccines by immunogenicity studies that show non-inferior immune responses and similar clinical efficacy compared to the three-dose schedule. So far, natural competition between HPV types has not been confirmed and therefore vaccine-induced clinically significant type replacement is unlikely. The real-world effectiveness data showed cross-sectional reduction in the prevalence/incidence of vaccine-related HPV types, genital warts and precancerous cervical lesions in countries and regions with HPV vaccination coverage. These declines were evident not only in vaccinated females, but also in unvaccinated females and males, strongly suggesting herd protection. Despite an excellent safety profile consistently demonstrated in clinical trials and confirmed in real-life settings, recently invented controversial syndromes allegedly linked to HPV vaccines temporarily compromised some previously very successful vaccination programs and significantly contributed to the failure of HPV vaccine implementation in some countries with the highest prevalence of cervical cancer. However, several safety studies failed to confirm any association of these syndromes with HPV vaccination in various settings and geographic locations. The main challenges remain implementing HPV vaccination in national vaccination programs, especially in low-and middle-income countries with the highest burden of cervical cancer, and achieving and sustaining high vaccine coverage rates.

Streptococcus pneumoniae Otitis Media Pathogenesis and How It Informs Our Understanding of Vaccine Strategies

PURPOSE OF REVIEW

This study aimed to review the literature regarding the mechanisms of transition from asymptomatic colonization to induction of otitis media and how the insight into the pathogenesis of otitis media has the potential to help design future otitis media-directed vaccines.

RECENT FINDINGS

Respiratory viruses have long been shown to predispose individuals to bacterial respiratory infections, such as otitis media. Recent information suggests that Streptococcus pneumoniae, which colonize the nasopharynx asymptomatically, can sense potentially "threatening" changes in the nasopharyngeal environment caused by virus infection by upregulating specific sets of genes involved in biofilm release, dissemination from the nasopharynx to other sites, and protection against the host immune system. Furthermore, an understanding of the transcriptional and proteomic changes occurring in bacteria during transition to infection has led to identification of novel vaccine targets that are disease-specific and will not affect asymptomatic colonization. This approach will avoid major changes in the delicate balance of microorganisms in the respiratory tract microbiome due to elimination of S. pneumoniae.

SUMMARY

Our recent findings are reviewed in the context of the current literature on the epidemiology and pathogenesis of otitis media. We also discuss how other otopathogens, such as Haemophilus influenzae and Moraxella catarrhalis, as well as the normal respiratory microbiome, can modulate the ability of pneumococci to cause infection. Furthermore, the unsatisfactory protection offered by the pneumococcal conjugate vaccines is highlighted and we review potential future strategies emerging to confer a more specific protection against otitis media.

Global Routine Vaccination Coverage, 2015

In 1974, the World Health Organization (WHO) established the Expanded Program on Immunization* to provide protection against six vaccine-preventable diseases through routine infant immunization (1). Based on 2015 WHO and United Nations Children's Fund (UNICEF) estimates, global coverage with the third dose of diphtheria-tetanus-pertussis vaccine (DTP3), the first dose of measles-containing vaccine (MCV1) and the third dose of polio vaccine (Pol3) has remained stable (84%-86%) since 2010. From 2014 to 2015, estimated global coverage with the second MCV dose (MCV2) increased from 39% to 43% by the end of the second year of life and from 58% to 61% when older age groups were included. Global coverage was higher in 2015 than 2010 for newer or underused vaccines, including rotavirus vaccine, pneumococcal conjugate vaccine (PCV), rubella vaccine, Haemophilus influenzae type b (Hib) vaccine, and 3 doses of hepatitis B (HepB3) vaccine. Coverage estimates varied widely by WHO Region, country, and district; in addition, for the vaccines evaluated (MCV, DTP3, Pol3, HepB3, Hib3), wide disparities were found in coverage by country income classification. Improvements in equity of access are necessary to reach and sustain higher coverage and increase protection from vaccine-preventable diseases for all persons.