Impact of 13-Valent Pneumococcal Conjugate Vaccine on Pneumococcal Meningitis, Burkina Faso, 2016-2017

The Divergent Effect of Different Infant Vaccination Schedules of the 13-Valent Pneumococcal Conjugate Vaccine on Serotype-Specific Immunological Memory

Pneumococcal vaccination schedules are traditionally assessed based on the antibody response. The Memory B Cell (MBC) response has been less studied, despite its role in the magnitude and longevity of protection. We compared the immune response to different vaccination schedules with the 13-valent Pneumococcal Conjugate Vaccine (PCV13) and investigated the relationship between MBCs and the antibody response. Total and pneumococcal serotype (PS)-specific MBCs, their subsets and PS-specific IgG antibodies induced by a 3 + 0 (group A), 2 + 1 (group B) or 3 + 1 (group C) schedule in healthy infants were studied before and 1 month after the last PCV13. The relatively immature IgM+IgD+ MBC subset was the predominant subset in all groups but was larger in group A compared to group B and group C, indicating that age might be a significant parameter of the composition of the MBC pool. PS-specific MBCs at baseline were higher in group A, but they increased significantly only in the groups receiving the booster schedules (groups B and C). PS-specific IgM-only MBCs at baseline positively corelated with the antibody response and the PS-specific swIg MBCs post-immunization. Our findings illustrate the importance of a booster dose for the enrichment of PS-specific immunological memory. IgM-only MBCs and swIg MBCs may serve as additional correlates of vaccine-induced protection.

Modelling control strategies for pneumococcal meningitis outbreaks in the African meningitis belt

INTRODUCTION

Pneumococcal meningitis outbreaks occur sporadically in the African meningitis belt. Outbreak control guidelines and interventions are well established for meningococcal but not pneumococcal meningitis. Mathematical modelling is a useful tool for assessing the potential impact of different pneumococcal control strategies. This work aimed to estimate the impact of reactive vaccination with pneumococcal conjugate vaccine (PCV) had it been implemented in past African meningitis belt outbreaks and assess their efficiency relative to existing routine infant immunisation with PCV.

METHODS & RESULTS

Using recent pneumococcal meningitis outbreaks in Burkina Faso, Chad, and Ghana as case studies, we investigated the potential impact of reactive vaccination. We calculated the number needed to vaccinate to avert one case (NNV) in each outbreak setting and over all outbreaks and compared this to the NNV for existing routine infant vaccination. We extended previous analyses of reactive vaccination by considering longer-term protection in vaccinees over five years, incorporating a proxy for indirect effects. We found that implementing reactive vaccination in previous pneumococcal meningitis outbreaks could have averted up to 10-20 % of outbreak cases, with the biggest potential impact in Brong Ahafo, Ghana (2015-2016) and Goundi, Chad (2009). The NNV, and hence the value of reactive vaccination, varied greatly. 'Large' (80 + cumulative modelled cases per 100,000 population) and/or 'prolonged' (exceeding a response threshold of 10 suspected cases per 100,000 per week for four weeks or more) outbreaks had NNV estimates under 10,000. For routine infant vaccination with PCV, the estimated NNV ranged from 3,100-5,600 in Burkina Faso and 1,500-2,600 in Ghana.

IMPLICATIONS

This analysis provides evidence to inform the design of pneumococcal meningitis outbreak response guidelines. Countries should consider reactive vaccination in each outbreak event, together with maintaining routine infant vaccination as the primary intervention to reduce pneumococcal disease burden and outbreak risk.

Serotype distribution of invasive pneumococcal disease from countries of the WHO Africa, Americas, Eastern Mediterranean, South-East Asia, and Western Pacific regions: a systematic literature review from 2010 to 2021

Background

Most publications on invasive pneumococcal disease (IPD) serotype distribution are from about 20 countries (Australia, Canada, China, European Union members, Japan, New Zealand, South Korea, and USA). Here, we reviewed the literature among underrepresented countries in the Americas (AMRO), Africa (AFRO), Eastern Mediterranean (EMRO), South-East Asia (SEARO), and Western Pacific (WPRO) WHO regions.

Methods

We performed a systematic review of the most recent IPD serotype surveillance publications (from 01/01/2010 to 31/12/2021, Medline/Embase) in those WHO regions. Selection criteria were delineated by contemporality, within-country geographical scope, and number of samples. Reported serotype distributions for each country were stratified by age group, pneumococcal conjugate vaccine (PCV) serotype category (considering undifferentiated serotypes), and PCV program period (pre-PCV, intermediate, or PCVhv [higher valency PCV formulation]). Pre-PCV period pooled data estimated PCV serotype category distribution by age group across WHO regions, while for the PCVhv period, country-level dataset tables were prepared.

Results

Of 2,793 publications screened, 107 were included (58 pediatric, 11 adult, 37 all ages, and one comprising every age group). One-third of eligible countries (51/135) published serotype distribution, ranging from 30 to 43% by WHO region. Considering number of samples per WHO region, a few countries prevailed: AMRO (Brazil), AFRO (South Africa, Malawi, and Burkina Faso), and WPRO (Taiwan). In the pre-PCV period, PCV13 formulation serotypes predominated: ranging from 74 to 85% in children and 58-86% in adults in the different WHO regions. The PCVhv period represented half of the most recent IPD surveillance by countries (26/51). Undifferentiated serotypes represented >20% of IPD from most countries (34/51).

Conclusion

Ubiquity of undifferentiated serotypes among the publications could constrain estimates of PCV program impact and of serotype coverage for newer PCVhv formulations; consequently, we recommend that countries favor techniques that identify serotypes specifically and, rather than reporting PCV formulation serotype distributions, provide serotype results individually.

Systematic review registration

The protocol has been prospectively registered at PROSPERO, identifier: CRD42021278501. https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=278501.

Pneumococcal Carriage in Burkina Faso After 13-Valent Pneumococcal Conjugate Vaccine Introduction and Before a Schedule Change

Background

In October 2013, Burkina Faso introduced 13-valent pneumococcal conjugate vaccine (PCV13) into the routine childhood immunization program using 3 primary doses with no booster. Previous pneumococcal carriage studies showed reductions in vaccine-type (VT) carriage in children aged <5 years but not in older age groups.

Methods

We conducted a cross-sectional, age-stratified pneumococcal carriage study among healthy persons aged ≥1 month in Bobo-Dioulasso in March 2020. Pneumococci isolated by culture from nasopharyngeal swabs (all participants) and oropharyngeal swabs (participants aged ≥5 years) were serotyped by polymerase chain reaction; a subset was serotyped by Quellung. Using data from a study with the same design from March 2017, we examined changes in pneumococcal carriage by age group.

Results

Among 1005 (2017) and 1002 (2020) enrolled participants, VT carriage decreased (21.6% to 15.9%; adjusted prevalence ratio [aPR], 0.76 [95% confidence interval {CI}, .63-.92]). By age group, decline in VT carriage was significant among children aged 5-14 years (28.9% to 16.3%; aPR, 0.57 [95% CI, .39-.84]) but not among children aged <5 years (22.4% to 19.1%; aPR, 0.87 [95% CI, .70-1.09]) or adults aged ≥15 years (12.0% to 5.5%; aPR, 0.52 [95% CI, .26-1.05]).

Conclusions

Between 3 and 6 years after PCV13 introduction, significant declines in VT carriage were observed in older children, possibly reflecting indirect effects of PCV13 use. VT carriage in children aged <5 years remained stable with almost 1 in 5 carrying VT pneumococci, suggesting limitations to a PCV schedule without a booster dose.

Optimal decision-making in relieving global high temperature-related disease burden by data-driven simulation

The rapid acceleration of global warming has led to an increased burden of high temperature-related diseases (HTDs), highlighting the need for advanced evidence-based management strategies. We have developed a conceptual framework aimed at alleviating the global burden of HTDs, grounded in the One Health concept. This framework refines the impact pathway and establishes systematic data-driven models to inform the adoption of evidence-based decision-making, tailored to distinct contexts. We collected extensive national-level data from authoritative public databases for the years 2010-2019. The burdens of five categories of disease causes - cardiovascular diseases, infectious respiratory diseases, injuries, metabolic diseases, and non-infectious respiratory diseases - were designated as intermediate outcome variables. The cumulative burden of these five categories, referred to as the total HTD burden, was the final outcome variable. We evaluated the predictive performance of eight models and subsequently introduced twelve intervention measures, allowing us to explore optimal decision-making strategies and assess their corresponding contributions. Our model selection results demonstrated the superior performance of the Graph Neural Network (GNN) model across various metrics. Utilizing simulations driven by the GNN model, we identified a set of optimal intervention strategies for reducing disease burden, specifically tailored to the seven major regions: East Asia and Pacific, Europe and Central Asia, Latin America and the Caribbean, Middle East and North Africa, North America, South Asia, and Sub-Saharan Africa. Sectoral mitigation and adaptation measures, acting upon our categories of Infrastructure & Community, Ecosystem Resilience, and Health System Capacity, exhibited particularly strong performance for various regions and diseases. Seven out of twelve interventions were included in the optimal intervention package for each region, including raising low-carbon energy use, increasing energy intensity, improving livestock feed, expanding basic health care delivery coverage, enhancing health financing, addressing air pollution, and improving road infrastructure. The outcome of this study is a global decision-making tool, offering a systematic methodology for policymakers to develop targeted intervention strategies to address the increasingly severe challenge of HTDs in the context of global warming.

Prevalence of prolonged otitis media with effusion among 2 to 3 years old Cameroonian children in the era of 13-valent pneumococcal conjugate vaccines

Objectives

There is data scarcity on the overall effects of pneumococcal conjugate vaccines (PCVs) on otitis media (OM) in low- and middle-income countries. The impact of the 13-valent PCV (PCV13) program on OM was evaluated in Cameroon where infant vaccination was implemented in July 2011 using a 3-dose primary series at 6, 10 and 14 weeks of age.

Methods

Through community-based surveillance, we used a retrospective cohort study design to assess OM prevalence among PCV13-vaccinated children aged 24 to 36 months in 2015. This was compared with a 2013 age-matched cohort of PCV13-unvaccinated children. OM was diagnosed by clinical inspection for chronic suppurative OM (CSOM) and tympanometry for OM with effusion (OME). CSOM was defined as draining of the middle ear with duration of more than 2 weeks and prolonged OME was defined as a flat 'type B' tympanogram. PCV13-vaccinated and PCV13-unvaccinated cohorts were compared by calculating prevalence odds ratios for OM and baseline characteristics.

Results

Altogether, 111 OM cases were identified; 42/433 (9.7%) in the PCV13-unvaccinated in 2013 and 69/413 (16.7%) in the PCV13-vaccinated cohort in 2015. In the 2013 baseline survey, 3/433 (0.7%) children were identified with unilateral CSOM compared to 9/413 (2.2%) in the PCV13-vaccinated cohort in 2015. Bilateral prolonged OME was diagnosed in 7/433 (1.6%) PCV13-unvaccinated children and in 12/413 (2.9%) in PCV13-vaccinated children. Proportions of children with unilateral prolonged OME were 31/433 (7.2%) in the PCV13-unvaccinated group compared with 48/413 (11.6%) in the PCV13-vaccinated group. Multivariate logistic regression analysis showed evidence that PCV13-vaccinated children in 2015 had 40% less risk of contracting OM compared to PCV13-unvaccinated children in 2013 (adjusted prevalence odds ratios = 0.60 [95% confidence interval: 0.38 to 0.94], P = 0.025). Additionally, attributable proportion estimates show that, 58% of OM infections among the PCV13-vaccinated group would still have occurred despite PCV13 vaccination.

Conclusion

Our findings provide significant evidence on the effect of PCV13 in decreasing OM or OME among children in this age group. It also supports justification for government's continuation of PCV13 immunization program in the absence of GAVI's funding. Further research is needed to assess the long-term impact of the PCV13 program on in OM Cameroon.

Implementation challenges and real-world impacts of switching pediatric vaccines: A global systematic literature review

Switching a vaccine for another on a pediatric national immunization program is often done for the betterment of society. However, if poorly implemented, switching vaccines could result in suboptimal transitions with negative effects. A systematic review was conducted to evaluate the existing knowledge from identifiable documents on implementation challenges of pediatric vaccine switches and the real-world impact of those challenges. Thirty-three studies met the inclusion criteria. We synthesized three themes: vaccine availability, vaccination program deployment, and vaccine acceptability. Switching pediatric vaccines can pose unforeseen challenges to health-care systems worldwide and additional resources are often required to overcome those challenges. Yet, the magnitude of the impact, especially economic and societal, was frequently under-researched with variability in reporting. Therefore, an efficient vaccine switch requires a thorough consideration of the added benefits of replacing the existing vaccine, preparation, planning, additional resource allocation, implementation timing, public-private partnerships, outreach campaigns, and surveillance for program evaluation.

Vaccine Uptake to Prevent Meningitis and Encephalitis in Shanghai, China

Multiple vaccines may prevent meningitis and encephalitis (M/E). In China, the meningococcal vaccine and Japanese encephalitis vaccine (JEV) have been included in the expanded program of immunization (EPI). The pneumococcal vaccine, Haemophilus influenzae type b (Hib) vaccine, rotavirus vaccine, and enterovirus 71 (EV-71) vaccine are non-EPI vaccines and are self-paid. We aim to investigate the uptake of these M/E vaccines in children and the related knowledge and health beliefs among family caregivers. A total of 1011 family caregivers with children aged 1-6 years in Shanghai, China were included in the study. The uptake of the pneumococcal vaccine, Hib-containing vaccine, rotavirus vaccine, and EV-71 vaccine remained at 44.0-48.1% in children, compared with the higher uptake of the meningococcal vaccine (88.8%) and JEV (87.1%). Moreover, family caregivers had limited knowledge on the M/E pathogens and possible vaccines. Their health beliefs were moderate to high. Then, a health belief model (HBM) and a structural equation model were established. The uptake of four non-EPI vaccines was significantly influenced by family income (β = 0.159), knowledge (β = 0.354), self-efficacy (β = 0.584), and perceived susceptibility (β = 0.212) within an HBM. Therefore, it warrants further improving the uptake rate for these non-EPI vaccines to prevent potential M/E in children. A specific health promotion may empower the caregivers' decision-making on childhood vaccination.

Decline in Vaccine-Type Streptococcus pneumoniae Serotypes Following Pneumococcal Conjugate Vaccine Introduction in Madagascar

BACKGROUND

The 10-valent conjugate vaccine (PCV10) was introduced into the Extended Program on Immunization in Madagascar. We assessed the impact of PCV10 on the targeted pneumococcal serotypes among children < 5 years of age at Centre Hospitalier Universitaire Mère Enfant Tsaralalàna.

METHOD

Between 2012 and December 2018, cerebrospinal fluid (CSF) samples were collected and tested for S. pneumoniae by culture, and antigen tests. The Sentinel Site Laboratory (SSL) referred available CSF samples to the Regional Reference Laboratory (RRL) for real-time polymerase chain reaction confirmatory testing and serotyping.

RESULTS

In total, 3616 CSF specimens were collected. The SSL referred 2716 to the RRL; 125 were positive for S. pneumoniae. At the RRL, 115 samples that tested positive for S. pneumoniae were serotyped; PCV10 serotypes accounted for 20%. Compared to the pre-PCV period, the proportion of S. pneumoniae detected declined from 22% to 6.6%, (P < .05), the proportion of PCV10 serotypes as the cause of pneumococcal meningitis cases declined by 26% following vaccine introduction.

CONCLUSIONS

In our findings, PCV10 introduction resulted in a decline of meningitis caused by S. pneumoniae and PCV10 vaccine serotypes.

Pneumococcal Carriage in Burkina Faso After 13-Valent Pneumococcal Conjugate Vaccine Introduction: Results From 2 Cross-sectional Population-Based Surveys

Background

Burkina Faso, a country in Africa’s meningitis belt, introduced 13-valent pneumococcal conjugate vaccine (PCV13) in October 2013, with 3 primary doses given at 8, 12 and 16 weeks of age. To assess whether the new PCV13 program controlled pneumococcal carriage, we evaluated overall and serotype-specific colonization among children and adults during the first 3 years after introduction.

Methods

We conducted 2 population-based, cross-sectional, age-stratified surveys in 2015 and 2017 in the city of Bobo-Dioulasso. We used standardized questionnaires to collect sociodemographic, epidemiologic, and vaccination data. Consenting eligible participants provided nasopharyngeal (all ages) and oropharyngeal (≥5 years only) swab specimens. Swab specimens were plated onto blood agar either directly (2015) or after broth enrichment (2017). Pneumococci were serotyped by conventional multiplex polymerase chain reaction. We assessed vaccine effect by comparing the proportion of vaccine-type (VT) carriage among colonized individuals from a published baseline survey (2008) with each post-PCV survey.

Results

We recruited 992 (2015) and 1005 (2017) participants. Among children aged <5 years, 42.8% (2015) and 74.0% (2017) received ≥2 PCV13 doses. Among pneumococcal carriers aged <1 year, VT carriage declined from 55.8% in 2008 to 36.9% in 2017 (difference, 18.9%; 95% confidence interval, 1.9%–35.9%; P = .03); among carriers aged 1–4 years, VT carriage declined from 55.3% to 31.8% (difference, 23.5%; 6.8%–40.2%; P = .004); and among participants aged ≥5 years, no significant change was observed.

Conclusion

Within 3 years of PCV13 implementation in Burkina Faso, we documented substantial reductions in the percentage of pneumococcal carriers with a VT among children aged <5 years, but not among persons aged ≥5 years. More time, a change in the PCV13 schedule, or both, may be needed to better control pneumococcal carriage in this setting.

Dynamics of Invasive Pneumococcal Disease in Israel in Children and Adults in the PCV13 Era: A Nationwide Prospective Surveillance

BACKGROUND

Following 13-valent pneumococcal conjugate vaccine (PCV13) implementation in infants worldwide, overall and vaccine-type invasive pneumococcal disease (IPD) rates declined in children, with variable indirect impact on adults.

METHODS

A population-based, prospective, nationwide active surveillance of IPD in Israel, 2004-2019 (for adults ≥18 years, 2009-2019). The 7-valent PCV (PCV7)/PCV13 were implemented in Israel in July 2009/November 2010, respectively, with >90% uptake in children <2 years. The 23-valent pneumococcal polysaccharide vaccine (PPV-23) uptake among >65 years was ~75%. For pre-PCV episodes with missing serotype, extrapolations were applied. Overall, PCV13 serotypes (VT13) and non-VT13 (NVT) incidence rates ratios (IRRs) comparing pre-PCV (2004-2008), early-PCV (2009-2011) and late-PCV13 (2016-2019) periods were calculated for different age groups.

RESULTS

Overall, 8,614 IPD cases were recorded. IPD rates declined by 67% in children <5 and 5-17 years, comparing late-PCV13 vs. pre-PCV periods (IRR=0.33; CI: 0.27-0.40; and IRR=0.33; CI: 0.21-0.50, respectively). For adults, comparing late-PCV13 vs. early-PCV periods, rates significantly declined by 53% in 18-44 years, while rates did not decline significantly in other age groups.VT13 rates significantly declined in all ages, with decline rates ranging between 94% in children <5 years and 60% in adults ≥85 years. NVT rates significantly increased in <5, 50-64 and ≥65 years age groups. In late-PCV13 period, serotypes 3, 14 and 19A remained the predominant VT13, while serotypes 8 and 12F emerged as the predominant NVT.

CONCLUSIONS

Continuous monitoring of circulating serotypes in all ages demonstrated direct and indirect PCV effects, which are essential for the development of new vaccination strategies.

Estimating the economic burden of pneumococcal meningitis and pneumonia in northern Ghana in the African meningitis belt post-PCV13 introduction

BACKGROUND

Ghana introduced 13-valent pneumococcal conjugate vaccine (PCV13) into the routine infant immunization program in 2012, using a three-dose primary series without a booster. Despite ≥ 88% reported three-dose vaccination coverage since 2013, PCV13-type pneumococcal meningitis outbreaks have occurred. We estimated the ongoing economic burden of PCV13-type pneumococcal meningitis and pneumonia in northern Ghana, an area within the African meningitis belt with seasonal increases of pneumococcal meningitis post-PCV13 introduction, to inform PCV13 vaccination policy.

METHODS

We performed a cross-sectional survey among patients with pneumonia or meningitis at three hospitals in northern Ghana to determine patient-level costs (direct medical and nonmedical, indirect patient and caregiver costs) incurred in household, outpatient, and inpatient settings. Pneumonia burden was estimated using 2017-2018 administrative records. Pneumococcal meningitis burden was estimated using 2017-2018 case-based surveillance data. Economic burden was reported in 2019 U.S. dollars ($) from the societal perspective.

RESULTS

For an area with a total population of 5,068,521, our model estimated 6,441 PCV13-type pneumonia cases and 286 PCV13-type meningitis cases occurred in a typical year post-PCV13. In the base case scenario, the total economic burden was $5,230,035 per year ($777 per case). By age group, cost per PCV13-type pneumonia case was $423 (<5 years), $911 (5-14 years), and $784 (≥15 years); cost per PCV13-type meningitis case was $2,128 (<5 years), $3,247 (5-14 years), and $2,883 (≥15 years). Most (78.0-93.4%) of the total societal cost was due to indirect costs related to deaths from PCV13-type diseases.

CONCLUSIONS

The estimated economic burden of PCV13-type disease in northern Ghana remains substantial, especially in older children and adults who were expected to have benefited from indirect effects from infant immunization. Additional interventions such as changes in the infant immunization schedule, reactive vaccination, or catch-up PCV13 vaccination may be needed to control remaining vaccine-type disease.

Application of a Pneumococcal Serotype-specific Urinary Antigen Detection Test for Identification of Pediatric Pneumonia in Burkina Faso

BACKGROUND

Serotype-specific diagnosis of pneumococcal community-acquired pneumonia in children under age 5 years would mark a major advancement for understanding pneumococcal epidemiology and supporting vaccine decision-making.

METHODS

A Luminex technology-based multiplex urinary antigen detection (UAD) diagnostic assay was developed and subsequently validated in adults, but its applicability to children is unknown. This study aimed to set appropriate cutoffs for use of the UAD in a healthy pediatric population and apply these cutoffs in children with pneumonia in sub-Saharan Africa. The cutoffs were determined by assessing 379 urines obtained from healthy children under age 5 years from the Bobo-Dioulasso area for serotypes included in 13-valent pneumococcal conjugate vaccine (UAD-1) and the 11 other serotypes unique to 23-valent pneumococcal polysaccharide vaccine (UAD-2).

RESULTS

Based on the assigned cutoff values, among 108 children who met the World Health Organization consolidation endpoint criteria, UAD-1 and UAD-2 were positive in 23.3% and 8.3%, respectively; among 364 children with clinically suspected pneumonia who did not meet the World Health Organization criteria, UAD-1 and UAD-2 were positive for 6.6% and 3.6%, respectively. Pneumococcal carriage prevalence was similar among pneumonia cases (30%) versus controls (35%) as was semiquantitative carriage density.

CONCLUSIONS

UAD-1 and UAD-2 were able to distinguish community controls from children with pneumonia, particularly pneumonia with consolidation. Future studies are needed to confirm these results and more fully assess the contribution of pneumococcal carriage and concurrent viral infection.

Pneumococcal vaccine implementation in the African meningitis belt countries: the emerging need for alternative strategies

Introduction: Besides meningococcal disease, the African meningitis belt (AMB) region is also affected by pneumococcal disease. Most AMB countries have introduced pneumococcal conjugate vaccines (PCV) following a schedule of three primary doses without a booster or a catch-up campaign. PCV is expected to help control pneumococcal disease through both direct and indirect effects. Whether and how fast this will be achieved greatly depends on implementation strategies. Pre-PCV data from the AMB indicate high carriage rates of the pneumococcus, not only in infants but also in older children, and a risk of disease and death that spans lifetime. Post-PCV data highlight the protection of vaccinated children, but pneumococcal transmission remains important, resulting in a lack of indirect protection for unvaccinated persons.Areas covered: A non-systematic literature review focused on AMB countries. Relevant search terms were used in PubMed, and selected studies before and after PCV introduction were summarized narratively to appraise the suitability of current PCV programmatic strategies.Expert opinion: The current implementation strategy of PCV in the AMB appears suboptimal regarding the generation of indirect protection. We propose and discuss alternative programmatic strategies, including the implementation of broader age group mass campaigns, to accelerate disease control in this high transmission setting.

Fletcher M, Koki Ndombo P, Boula A, Ashukem NT, Ngo Baleba M, Kingue Bebey RS, Nkolo Mviena EG, Tageube J, Kobela Mbollo M, Koulla-Shiro S, Madhi S, Njanpop-Lafourcade BM, Mohammad A, Begier E, Southern J, Beavon R, Gessner B. Impact of 13-valent pneumococcal conjugate vaccine on laboratory-confirmed pneumococcal meningitis and purulent meningitis among children ˂5 years in Cameroon, 2011-2018

BACKGROUND

The 13-valent pneumococcal conjugate vaccine (PCV13) entered Cameroon's childhood national immunization programme (NIP) in July 2011 under a 3-dose schedule (6, 10, 14 weeks of age) without any catch-up. We described the impact of PCV13 onserotype distribution among pneumococcal meningitis cases over time.

METHODS

We used laboratory-based sentinel surveillance data to identify meningitis cases among 2- to 59-month-old children with clinically-suspected bacterial meningitis (CSBM) admitted to hospitals in Yaoundé (August 2011-December 2018). Purulent meningitis cases had a cerebrospinal fluid (CSF) white blood cell (WBC) count ≥20 per mm3. Pneumococcal meningitis cases had S. pneumoniae identified from CSF, with serotyping by polymerase chain reaction. Years 2011-2014 were described as early PCV13 era (EPE) and years 2015-2018 as late PCV13 era (LPE) impact periods.

RESULTS

Among children hospitalized with CSBM who had a lumbar puncture obtained, there was no significant change from the EPE versus the LPE in the percentage identified with purulent meningitis: 7.5% (112/1486) versus 9.4% (154/1645), p = 0.0846. The percentage of pneumococcal meningitis cases due to PCV13 vaccine-serotype (VST) decreased from 62.0% (31/50) during the EPE to 35.8% (19/53) in the LPE, p = 0.0081. The most frequent pneumococcal meningitis VSTs during the EPE were 6A/6B (30%) and 5 (6%), and during the LPE were 14 (13.2%), 3 (7.6%), 4 (5.6%) and 18C (5.6%).

CONCLUSION

Four to seven years after PCV13 introduction, the proportion of pneumococcal meningitis due to vaccine serotypes has declined, mainly due to reductions of serotypes 6A/6B, 1, 19A, and 23F; nevertheless, PCV13 VSTs remain common. Because the analyzed surveillance system was not consistent or population based, we could not estimate incidence or overall impact; this emphasizes the need for improved surveillance to document further the utility of PCV13 immunization in Cameroon.

Global Landscape Review of Serotype-Specific Invasive Pneumococcal Disease Surveillance among Countries Using PCV10/13: The Pneumococcal Serotype Replacement and Distribution Estimation (PSERENADE) Project

Serotype-specific surveillance for invasive pneumococcal disease (IPD) is essential for assessing the impact of 10- and 13-valent pneumococcal conjugate vaccines (PCV10/13). The Pneumococcal Serotype Replacement and Distribution Estimation (PSERENADE) project aimed to evaluate the global evidence to estimate the impact of PCV10/13 by age, product, schedule, and syndrome. Here we systematically characterize and summarize the global landscape of routine serotype-specific IPD surveillance in PCV10/13-using countries and describe the subset that are included in PSERENADE. Of 138 countries using PCV10/13 as of 2018, we identified 109 with IPD surveillance systems, 76 of which met PSERENADE data collection eligibility criteria. PSERENADE received data from most (n = 63, 82.9%), yielding 240,639 post-PCV10/13 introduction IPD cases. Pediatric and adult surveillance was represented from all geographic regions but was limited from lower income and high-burden countries. In PSERENADE, 18 sites evaluated PCV10, 42 PCV13, and 17 both; 17 sites used a 3 + 0 schedule, 38 used 2 + 1, 13 used 3 + 1, and 9 used mixed schedules. With such a sizeable and generally representative dataset, PSERENADE will be able to conduct robust analyses to estimate PCV impact and inform policy at national and global levels regarding adult immunization, schedule, and product choice, including for higher valency PCVs on the horizon.

Serotype Distribution of Remaining Pneumococcal Meningitis in the Mature PCV10/13 Period: Findings from the PSERENADE Project

Pneumococcal conjugate vaccine (PCV) introduction has reduced pneumococcal meningitis incidence. The Pneumococcal Serotype Replacement and Distribution Estimation (PSERENADE) project described the serotype distribution of remaining pneumococcal meningitis in countries using PCV10/13 for least 5-7 years with primary series uptake above 70%. The distribution was estimated using a multinomial Dirichlet regression model, stratified by PCV product and age. In PCV10-using sites (N = 8; cases = 1141), PCV10 types caused 5% of cases <5 years of age and 15% among ≥5 years; the top serotypes were 19A, 6C, and 3, together causing 42% of cases <5 years and 37% ≥5 years. In PCV13-using sites (N = 32; cases = 4503), PCV13 types caused 14% in <5 and 26% in ≥5 years; 4% and 13%, respectively, were serotype 3. Among the top serotypes are five (15BC, 8, 12F, 10A, and 22F) included in higher-valency PCVs under evaluation. Other top serotypes (24F, 23B, and 23A) are not in any known investigational product. In countries with mature vaccination programs, the proportion of pneumococcal meningitis caused by vaccine-in-use serotypes is lower (≤26% across all ages) than pre-PCV (≥70% in children). Higher-valency PCVs under evaluation target over half of remaining pneumococcal meningitis cases, but questions remain regarding generalizability to the African meningitis belt where additional data are needed.

Evaluation of pneumococcal meningitis clusters in Burkina Faso and implications for potential reactive vaccination

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From 2011 to 2017, Burkina Faso had 20 pneumococcal meningitis clusters of ≥ 5 cases per district/week.

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Clusters had a maximum weekly incidence of 7 cases and a maximum duration of 4 weeks.

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Most clusters occurred prior to 13-valent pneumococcal conjugate vaccine introduction.

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Clusters were caused by a mixture of serotypes, with serotype 1 being most common.

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Due to the limited cluster size and duration, there were no clear indications for reactive vaccination.

Background

To better understand how to prevent and respond to pneumococcal meningitis outbreaks in the meningitis belt, we retrospectively examined Burkina Faso’s case-based meningitis surveillance data for pneumococcal meningitis clusters and assessed potential usefulness of response strategies.

Methods

Demographic and clinical information, and cerebrospinal fluid laboratory results for meningitis cases were collected through nationwide surveillance. Pneumococcal cases were confirmed by culture, polymerase chain reaction (PCR), or latex agglutination; strains were serotyped using PCR. We reviewed data from 2011 to 2017 to identify and describe clusters of ≥ 5 confirmed pneumococcal meningitis cases per week in a single district. We assessed whether identified clusters met the 2016 WHO provisional pneumococcal meningitis outbreak definition: a district with a weekly incidence of >5 suspected meningitis cases/100,000 persons, >60% of confirmed meningitis cases caused by Streptococcus pneumoniae, and >10 confirmed pneumococcal meningitis cases.

Results

Twenty pneumococcal meningitis clusters were identified, with a maximum weekly incidence of 7 cases and a maximum duration of 4 weeks. Most identified clusters (15/20; 75%) occurred before nationwide introduction of 13-valent pneumococcal conjugate vaccine (PCV13) in October 2013. Most cases were due to serotype 1 (74%), 10% were due to PCV13 serotypes besides serotype 1, and 8 clusters had >1 serotype. While 6 identified clusters had a weekly incidence of >5 suspected cases/100,000 and all 20 clusters had >60% of confirmed meningitis cases due to S. pneumoniae, no cluster had >10 confirmed pneumococcal meningitis cases in a single week.

Conclusions

Following PCV13 introduction, pneumococcal meningitis clusters were rarely detected, and none met the WHO provisional pneumococcal outbreak definition. Due to the limited cluster size and duration, there were no clear instances where reactive vaccination could have been useful. More data are needed to inform potential response strategies.

Isolation and identification of Streptococcus pneumoniae serotype 6B from a patient with bacterial meningitis infection in Jakarta, Indonesia

CNS infection is a life-threatening condition in developing countries and Streptococcus pneumoniae has been reported as the most common cause of bacterial meningitis; however, there is limited data on pneumococcal meningitis in Indonesia. This cross-sectional study aimed to isolate and identity S. pneumoniae strains from cerebrospinal fluid (CSF) specimens collected as part of routine testing from patients with clinically diagnosed central nervous system infection at a national referral hospital in Jakarta, Indonesia in 2017. S. pneumoniae isolation and identification were performed using conventional culture and molecular tools. Antibiotic susceptibility patterns were monitored through minimum inhibitory concentration testing. From 147 CSF specimens, one S. pneumoniae strain was identified from a patient with bacterial meningitis symptoms. The isolate was serotype 6B (ST5661) and susceptible to 18 antimicrobial agents tested, including penicillin, tetracycline, and the macrolide group. Our data provide insights into the epidemiology of invasive pneumococcal disease in Indonesia.

Future Directions for Meningitis Surveillance and Vaccine Evaluation in the Meningitis Belt of Sub-Saharan Africa

In sub-Saharan Africa, bacterial meningitis remains a significant public health problem, especially in the countries of the meningitis belt, where Neisseria meningitidis serogroup A historically caused large-scale epidemics. In 2014, MenAfriNet was established as a consortium of partners supporting strategic implementation of case-based meningitis surveillance to monitor meningitis epidemiology and impact of meningococcal serogroup A conjugate vaccine (MACV). MenAfriNet improved data quality through use of standardized tools, procedures, and laboratory diagnostics. MenAfriNet surveillance and study data provided evidence of ongoing MACV impact, characterized the burden of non-serogroup A meningococcal disease (including the emergence of a new epidemic clone of serogroup C), and documented the impact of pneumococcal conjugate vaccine. New vaccines and schedules have been proposed for future implementation to address the remaining burden of meningitis. To support the goals of "Defeating Meningitis by 2030," MenAfriNet will continue to strengthen surveillance and support research and modeling to monitor the impact of these programs on meningitis burden in sub-Saharan Africa.

Bacterial Meningitis Epidemiology in Five Countries in the Meningitis Belt of Sub-Saharan Africa, 2015-2017

BACKGROUND

The MenAfriNet Consortium supports strategic implementation of case-based meningitis surveillance in key high-risk countries of the African meningitis belt: Burkina Faso, Chad, Mali, Niger, and Togo. We describe bacterial meningitis epidemiology in these 5 countries in 2015-2017.

METHODS

Case-based meningitis surveillance collects case-level demographic and clinical information and cerebrospinal fluid (CSF) laboratory results. Neisseria meningitidis, Streptococcus pneumoniae, or Haemophilus influenzae cases were confirmed and N. meningitidis/H. influenzae were serogrouped/serotyped by real-time polymerase chain reaction, culture, or latex agglutination. We calculated annual incidence in participating districts in each country in cases/100 000 population.

RESULTS

From 2015-2017, 18 262 suspected meningitis cases were reported; 92% had a CSF specimen available, of which 26% were confirmed as N. meningitidis (n = 2433; 56%), S. pneumoniae (n = 1758; 40%), or H. influenzae (n = 180; 4%). Average annual incidences for N. meningitidis, S. pneumoniae, and H. influenzae, respectively, were 7.5, 2.5, and 0.3. N. meningitidis incidence was 1.5 in Burkina Faso, 2.7 in Chad, 0.4 in Mali, 14.7 in Niger, and 12.5 in Togo. Several outbreaks occurred: NmC in Niger in 2015-2017, NmC in Mali in 2016, and NmW in Togo in 2016-2017. Of N. meningitidis cases, 53% were NmC, 30% NmW, and 13% NmX. Five NmA cases were reported (Burkina Faso, 2015). NmX increased from 0.6% of N. meningitidis cases in 2015 to 27% in 2017.

CONCLUSIONS

Although bacterial meningitis epidemiology varied widely by country, NmC and NmW caused several outbreaks, NmX increased although was not associated with outbreaks, and overall NmA incidence remained low. An effective low-cost multivalent meningococcal conjugate vaccine could help further control meningococcal meningitis in the region.