Public health impact of pneumococcal conjugate vaccine infant immunization programs: assessment of invasive pneumococcal disease burden and serotype distribution

National recommendations for adult pneumococcal vaccination in countries of the WHO regions of Americas, Africa, Eastern Mediterranean, South East Asia, and Western Pacific

BACKGROUND

Adults who are elderly or who have underlying health conditions are at particular risk of Streptococcus pneumoniae infections, and pneumococcal vaccines are available. Nonetheless, only national recommendations from countries of North America and Europe have been previously reviewed in the literature.

METHODS

Consequently, we aimed to collate national guidelines for adult pneumococcal immunization across the 161 countries within the World Health Organization (WHO) regions-the Americas (except Canada and the United States of America), Africa, Eastern Mediterranean, South East Asia, and Western Pacific-from country-level official websites and documents, from the WHO portal, and from direct contact with public health officials, pertinent governmental sources, or local vaccination experts.

RESULTS

For 40.4 % (65/161) of these countries, adult pneumococcal vaccination information was available. Among these 65 with available information, 63.1 % (41/65) include adult pneumococcal vaccination in the national vaccination schedule: 58.5 % (24/41) recommend vaccination both for older adults and for risk groups, while 9.8 % (4/41) recommend it only for older adults, and 31.7 % (13/41) only for risk groups. Of note, among the 13 national risk based-only recommendations, 30.8 % (4/13) are age-dependent and strictly reserved for older adults. The regions where age-based adult pneumococcal vaccination recommendations seem to predominate are South East Asia, Western Pacific, and the Americas. The threshold for age-based pneumococcal vaccination recommendations varies between 50 and 70 years of age. The Americas has the highest proportion of countries with risk-based recommendations. Three-quarters of these countries include PCV and PPV23 in the recommendations, most often given in sequence.

CONCLUSIONS

Less than half of countries of the five WHO regions analyzed have accessible information on adult pneumococcal vaccination, and only 25.5 % (41/161) of all countries reviewed recommend adult pneumococcal immunization within the national vaccination schedule. Policymakers should consider extending pneumococcal vaccination guidelines-adapted to national priorities for adult healthcare-as based on local age demographics and risk factor predominance.

Implications of Cross-Reactivity and Cross-Protection for Pneumococcal Vaccine Development

Pneumococcal vaccines are a cornerstone for the prevention of pneumococcal diseases, reducing morbidity and mortality in children and adults worldwide. Pneumococcal vaccine composition is based on the polysaccharide capsule of Streptococcus pneumoniae, which is one of the most important identified contributors to the pathogen's virulence. Similarities in the structural composition of polysaccharides included in licensed pneumococcal vaccines may result in cross-reactivity of immune response against closely related serotypes, including serotypes not included in the vaccine. Therefore, it is important to understand whether cross-reactive antibodies offer clinical protection against pneumococcal disease. This review explores available evidence of cross-reactivity and cross-protection associated with pneumococcal vaccines, the challenges associated with the assessment of cross-reactivity and cross-protection, and implications for vaccine design and development.

Comparative genomic and morphological analyses of capsular and capsular-deficient pneumococcal strains simultaneously isolated from a patient with invasive pneumococcal disease

INTRODUCTION

To understand the in-vivo dynamics in pneumococci, investigation into the carriage in patients with invasive pneumococcal disease (IPD) is extremely important.

METHODS

To clarify genomic and morphological differences between pneumococcal strains simultaneously isolated from different sites in a patient with IPD, we conducted comparative analyses of two strains. A capsular strain isolated from the blood and a non-capsular strain isolated from the sputum of a patient with IPD were used.

RESULTS

The strain isolated from blood was serotype 24B with capsule. The strain isolated from sputum with capsular type 24 genes was non-encapsulated, and genomic analysis revealed an insertion region in the wcxK gene. Its biofilm-forming capacity was higher than that of the capsular strain, as was that of the pspK-positive true non-encapsulated strain. Furthermore, observing the microbe using transmission electron microscopy revealed that the strain isolated from sputum lacked a capsule, like the pspK-positive true non-encapsulated strain.

CONCLUSIONS

Our analysis of the two strains isolated from the blood and sputum of a patient with IPD showed one possible in-vivo morphological change in Streptococcus pneumoniae.

Clinical and economic burden of acute otitis media caused by Streptococcus pneumoniae in European children, after widespread use of PCVs-A systematic literature review of published evidence

BACKGROUND

Acute otitis media (AOM) is a common childhood disease frequently caused by Streptococcus pneumoniae. Pneumococcal conjugate vaccines (PCV7, PCV10, PCV13) can reduce the risk of AOM but may also shift AOM etiology and serotype distribution. The aim of this study was to review estimates from published literature of the burden of AOM in Europe after widespread use of PCVs over the past 10 years, focusing on incidence, etiology, serotype distribution and antibiotic resistance of Streptococcus pneumoniae, and economic burden.

METHODS

This systematic review included published literature from 31 European countries, for children aged ≤5 years, published after 2011. Searches were conducted using PubMed, Embase, Google, and three disease conference websites. Risk of bias was assessed with ISPOR-AMCP-NPC, ECOBIAS or ROBIS, depending on the type of study.

RESULTS

In total, 107 relevant records were identified, which revealed wide variation in study methodology and reporting, thus limiting comparisons across outcomes. No homogenous trends were identified in incidence rates across countries, or in detection of S. pneumoniae as a cause of AOM over time. There were indications of a reduction in hospitalization rates (decreases between 24.5-38.8% points, depending on country, PCV type and time since PCV introduction) and antibiotic resistance (decreases between 14-24%, depending on country), following the widespread use of PCVs over time. The last two trends imply a potential decrease in economic burden, though this was not possible to confirm with the identified cost data. There was also evidence of an increase in serotype distributions towards non-vaccine serotypes in all of the countries where non-PCV serotype data were available, as well as limited data of increased antibiotic resistance within non-vaccine serotypes.

CONCLUSIONS

Though some factors point to a reduction in AOM burden in Europe, the burden still remains high, residual burden from uncovered serotypes is present and it is difficult to provide comprehensive, accurate and up-to-date estimates of said burden from the published literature. This could be improved by standardised methodology, reporting and wider use of surveillance systems.

Pneumococcal sialidase promotes bacterial survival by fine-tuning of pneumolysin-mediated membrane disruption

Pneumolysin (Ply) is an indispensable cholesterol-dependent cytolysin for pneumococcal infection. Although Ply-induced disruption of pneumococci-containing endosomal vesicles is a prerequisite for the evasion of endolysosomal bacterial clearance, its potent activity can be a double-edged sword, having a detrimental effect on bacterial survivability by inducing severe endosomal disruption, bactericidal autophagy, and scaffold epithelial cell death. Thus, Ply activity must be maintained at optimal levels. We develop a highly sensitive assay to monitor endosomal disruption using NanoBiT-Nanobody, which shows that the pneumococcal sialidase NanA can fine-tune Ply activity by trimming sialic acid from cell-membrane-bound glycans. In addition, oseltamivir, an influenza A virus sialidase inhibitor, promotes Ply-induced endosomal disruption and cytotoxicity by inhibiting NanA activity in vitro and greater tissue damage and bacterial clearance in vivo. Our findings provide a foundation for innovative therapeutic strategies for severe pneumococcal infections by exploiting the duality of Ply activity.

Streptococcus pneumoniae serotype 3 population structure in the era of conjugate vaccines, 2001-2018

Background. Despite use of highly effective conjugate vaccines, invasive pneumococcal disease (IPD) remains a leading cause of morbidity and mortality and disproportionately affects Indigenous populations. Although included in the 13-valent pneumococcal conjugate vaccine (PCV13), which was introduced in 2010, serotype 3 continues to cause disease among Indigenous communities in the Southwest USA. In the Navajo Nation, serotype 3 IPD incidence increased among adults (3.8/100 000 in 2001-2009 and 6.2/100 000 in 2011-2019); in children the disease persisted although the rates dropped from 5.8/100 000 to 2.3/100 000.Methods. We analysed the genomic epidemiology of serotype 3 isolates collected from 129 adults and 63 children with pneumococcal carriage (n=61) or IPD (n=131) from 2001 to 2018 of the Navajo Nation. Using whole-genome sequencing data, we determined clade membership and assessed changes in serotype 3 population structure over time.Results. The serotype 3 population structure was characterized by three dominant subpopulations: clade II (n=90, 46.9 %) and clade Iα (n=59, 30.7 %), which fall into Clonal Complex (CC) 180, and a non-CC180 clade (n=43, 22.4 %). The proportion of clade II-associated IPD cases increased significantly from 2001 to 2010 to 2011-2018 among adults (23.1-71.8 %; P<0.001) but not in children (27.3-33.3 %; P=0.84). Over the same period, the proportion of clade II-associated carriage increased; this was statistically significant among children (23.3-52.6 %; P=0.04) but not adults (0-50.0 %, P=0.08).Conclusions. In this setting with persistent serotype 3 IPD and carriage, clade II has increased since 2010. Genomic changes may be contributing to the observed trends in serotype 3 carriage and disease over time.

Prevalence and serotype distribution of nasopharyngeal carriage of Streptococcus pneumoniae among healthy children under 5 years of age in Hainan Province, China

BACKGROUND

The thirteen-valent pneumococcal conjugate vaccine (PCV13) is not included in the national immunization program and is administered voluntarily with informed consent in China. In preparation for assessing the impact of pilot introduction in Hainan Province, we conducted a carriage study among children under 5 years of age from four locations in Hainan Province, China.

METHODS

From March to June 2022, nasopharyngeal (NP) swabs, collected from healthy children aged younger than 59 months who lived in the 4 different locations (Haikou, Wanning, Baisha and Qiongzhong) in Hainan Province, were tested for pneumococcus using conventional culture. Pneumococcal isolates were serotyped using the Quellung reaction. Risk factors associated with pneumococcal colonization were assessed using univariate analysis and multivariable logistic regression adjusting for age, daycare attendance and other factors.

RESULTS

Pneumococcus was isolated in 710 (30.4%) of the 2333 children enrolled. Of 737 pneumococci, 29 serotypes were identified; 60.9% were PCV13 serotypes; the most common vaccine serotypes were 6B (20.4%), 19F (13.0%), 6A (11.9%) and 23F (6.1%); and the most common nonvaccine serotypes were 23A (12.9%), 34 (6.1%) and nontypeable (NT) pneumococci (5.6%). Children vaccinated with PCV13 had lower carriage (17.7% vs 32.5%; P = 0.0001) and fewer PCV13 serotypes (41.9% vs 62.7%; P = 0.0017) compared to unimmunized children. After adjustment, NP carriage was higher among children attending daycare (aOR = 2.3, 95% CI: 1.7-3.2), living in rural areas (aOR = 1.4, 95% CI: 1.1-1.8), living with siblings (aOR = 1.3, 95% CI: 1.0-1.6) and whose mothers had completed senior high/technical secondary school (aOR = 1.5, 95% CI: 1.1-2.0). In contrast, completion of 3-4 doses of PCV13 were associated with a lower carriage rate (aOR = 0.6, 95% CI: 0.4-0.9).

CONCLUSIONS

We established the baseline of pneumococcal carriage, serotype distribution and PCV13 immunization rates among healthy children under 5 years of age in Hainan Province, prior to the introduction of PCV13 into the national immunization program. The high proportion of PCV13 serotypes suggests that PCV13 introduction will likely have a substantial impact on pneumococcal carriage in Hainan Province.

Potential serotype-specific effectiveness against IPD of pneumococcal conjugate vaccines V114 and PCV20 in children given a 2+1 dosing regimen

BACKGROUND

Next generation, higher valency pneumococcal conjugate vaccines (PCVs) are assessed and licensed by comparing the immune response across serotypes shared with the PCVs that are standard of care for prevention of pneumococcal disease.

METHODS

Using a previously qualified method we predicted the serotype-specific vaccine effectiveness (VE) against invasive pneumococcal disease of V114 and PCV20 for the serotypes shared with PCV13 in an EU, Russian, and Australian pediatric population that is recommended to receive a 2 + 1 dosing regimen.

RESULTS

The estimated protective antibody concentrations ranged from 0.03 (serotype 23F) to 1.49 µg/mL (serotype 19F). Predicted VE values for V114 ranged from 79% (serotype 5) to 100% (serotype 23F). V114 had comparable effectiveness to PCV13 for all but one of shared serotypes, with predicted higher effectiveness (in V114) against serotype 3 (93% vs. 65%). Predicted VE values for PCV20 ranged from 47% (serotype 3) to 91% (serotype 14). PCV20 predicted VE was lower than PCV13's for serotypes 4, 19F, 23F, 1, 3, 5, 6A, 7F, and 19A.

CONCLUSIONS

Predicted serotype-specific VE values suggest that, with a 2 + 1 dosing regimen, V114 will have greater effectiveness than PCV20 against PCV13 serotypes, particularly for the still-prevalent serotype 3. Real-world VE studies will ultimately provide clarity on the effectiveness of novel PCVs and support further confidence in and/or improvements to modeling efforts.

Emerging pneumococcal serotypes in Iraq: scope for improved vaccine development

Pneumococcal disease is a global public health concern as it affects the young, aged and the immunocompromised. The development of pneumococcal vaccines and their incorporation in the immunization programs has helped to reduce the global burden of disease. However, serotype replacement and the emergence of non-vaccine serotypes as well as the persistence of a few vaccine serotypes underscores the need for development of new and effective vaccines against such pneumococcal serotypes. In the Middle East, places of religious mass gatherings are a hotspot for disease transmission in addition to the global risk factors. Therefore, the periodic surveillance of pneumococcal serotypes circulating in the region to determine the effectiveness of existing prevention strategies and develop improved vaccines is warranted. Currently, there is a lack of serotype prevalence data for Iraq due to inadequate surveillance in the region. Thus, this review aims to determine the pneumococcal serotypes circulating in Iraq which may help in the development and introduction of improved pneumococcal vaccines in the country.

Recent changes to adult national immunization programs for pneumococcal vaccination in Europe and how they impact coverage: A systematic review of published and grey literature

Despite widespread use of pneumococcal vaccines throughout Europe, the burden of pneumococcal disease (PD) in adults is considerable. To mitigate this burden, National Immunization Technical Advisory Groups (NITAGs) and Health Technology Assessment (HTA) agencies assess the value of different vaccine schedules for protecting against PD. The aim of this review was to assess the evidence and rationales used by NITAGs/HTA agencies, when considering recent changes to National Immunization Programs (NIPs) for adults, and how identified changes affected vaccine coverage rates (VCRs). A systematic review was conducted of published literature from PubMed® and Embase®, and gray literature from HTA/NITAG websites from the last 5 y, covering 31 European countries. Evidence related to NIP recommendations, epidemiology (invasive PD, pneumonia), health economic assessments and VCRs were collected and synthesized. Eighty-four records providing data for 26 countries were identified. Of these, eight described explicit changes to NIPs for adults in seven countries. Despite data gaps, some trends were observed; first, there appears to be a convergence of NIP recommendations in many countries toward sequential vaccination, with a pneumococcal conjugate vaccine (PCV), followed by pneumococcal polysaccharide vaccine 23. Second, reducing economic or healthcare burden were common rationales for implementing changes. Third, most health economic analyses assessing higher-valency PCVs for adults found its inclusion in NIPs cost-effective. Finally, higher coverage rates were seen in most cases where countries had expanded their NIPs to cover at-risk populations. The findings can encourage agencies to improve surveillance systems and work to reach the NIP's target populations more effectively.

Safety and Immunogenicity of V114 in Preterm Infants: A Pooled Analysis of Four Phase Three Studies

BACKGROUND

Risk of invasive pneumococcal disease is 3-fold higher in preterm versus full-term infants. V114 is a 15-valent pneumococcal conjugate vaccine (PCV) containing the 13 serotypes in PCV13 plus 2 unique serotypes, 22F and 33F. A pooled subgroup analysis was performed in preterm infants (<37 weeks gestational age) enrolled in 4 pediatric phase 3 studies evaluating the safety and immunogenicity of different 4-dose regimens of V114 or PCV13.

METHODS

Healthy preterm infants were randomized 1:1 to receive V114/PCV13 in the 4 studies. Safety was evaluated as the proportion of participants with adverse events (AEs) following receipt of PCV. Serotype-specific antipneumococcal immunoglobulin G (IgG) geometric mean concentrations, IgG response rates and opsonophagocytic activity geometric mean titers were measured at 30 days postdose 3, pretoddler dose and 30 days postdose 4.

RESULTS

V114 and PCV13 were administered to 174 and 180 participants, respectively. Mean gestational age was 35.4 weeks (range: 27 - <37 weeks). Proportions of participants with AEs were comparable between vaccination groups; most AEs experienced were of short duration (≤3 days) and mild-to-moderate intensity. V114-elicited IgG geometric mean concentrations, IgG response rates and opsonophagocytic activity geometric mean titers were generally comparable to PCV13 for the 13 shared serotypes and higher for serotypes 22F and 33F at 30 days postdose 3 and postdose 4.

CONCLUSIONS

In preterm infants, V114 was well tolerated and induced comparable immune responses to PCV13 for the 13 shared serotypes and higher immune responses to serotypes 22F and 33F. Results support the use of V114 in preterm infants.

A retrospective cohort study investigating the comparative effectiveness of pneumococcal vaccines against hospitalisation with otitis media and pneumonia in New Zealand

BACKGROUND

Since 2008 New Zealand has used three different formulations of pneumococcal vaccines on the national infant schedule, PCV7, PCV10 and PCV13, switching between PCV10 and PCV13 twice in 10 years. We have used New Zealand's linkable, administrative health data to examine the comparative risk of otitis media (OM) and pneumonia hospitalisations among children receiving three different pneumococcal conjugate vaccines (PCV).

METHODS

This was a retrospective cohort study using linked administrative data. Outcomes were otitis media, all cause pneumonia and bacterial pneumonia related hospitalisation for children in three cohorts representing periods where PCVs transitioned between PCV7, PCV10, PCV13 and back to PCV10 between 2011 and 2017. Cox's proportional hazard regression was used to provide hazard ratio estimates to compare outcomes for children vaccinated with different vaccine formulations and to adjust for different sub population characteristics.

RESULTS

Each observation period, where different vaccine formulations coincided, and therefore comparable with respect to age and the environment, included over fifty-thousand infants and children. PCV10 was associated with a reduced risk for OM compared with PCV7 (Adjusted HR 0.89, 95 %CI 0.82-0.97). There were no significant differences between PCV10 and PCV13 in risk of hospitalisation with either otitis media or all-cause pneumonia amongst the transition 2 cohort. In the 18 -month follow-up, after transition 3, PCV13 was associated with a marginally higher risk of all-cause pneumonia and otitis media compared to PCV10.

CONCLUSION

These results should offer reassurance about the equivalence of these pneumococcal vaccines against the broader pneumococcal disease outcomes OM and pneumonia.

Co-carriage of Staphylococcus aureus and Streptococcus pneumoniae among children younger than 2 years of age in a rural population in Pakistan

Objectives

Staphylococcus aureus and Streptococcus pneumoniae are common colonizers of the human nasopharynx. In this study, we describe S. aureus nasopharyngeal carriage and evaluate its association with S. pneumoniae carriage post-10-valent pneumococcal conjugate vaccine (PCV10) introduction in Pakistan.

Methods

A serial cross-sectional study was undertaken from 2014 to 2018, children <2 years were randomly selected, and nasopharyngeal swabs were collected using standard WHO guidelines. S. aureus and S. pneumoniae isolates were identified using standard methods and tested for antimicrobial susceptibility by the standard Kirby-Bauer disk-diffusion method as per Clinical & Laboratory Standards Institute (CLSI) recommendations. Regression analysis was used to determine predictors associated with S. aureus carriage.

Results

We enrolled 3140 children. S. aureus carriage prevalence was 5.6% (176/3140), and 50.1% (81/176) of the isolates were methicillin-resistant S. aureus (MRSA). S. aureus carriage was higher in the absence of pneumococcus compared to isolates in which pneumococcus was present (7.5% vs 5.0%). S. aureus carriage was negatively associated with pneumococcal carriage, being in 3rd and 4th year of enrollment, and vaccination with two and three PCV10 doses, in addition, fast breathing, ≥2 outpatients visits, and rainy season were positively associated. The following resistance rates were observed: 98.9% for penicillin, 74.4% for fusidic acid, and 23.3% for gentamicin, 10.2% for erythromycin, and 8.5% for cotrimoxazole. All isolates were susceptible to amikacin.

Conclusions

Overall S. aureus carriage prevalence was low, PCV10 vaccine was protective against the carriage. The proportion of MRSA carriage and antimicrobial resistance was high in this community warranting continuous monitoring for invasive infections.

Vaccine effectiveness of the pneumococcal polysaccharide and conjugated vaccines in elderly and high-risk populations in preventing invasive pneumococcal disease: a systematic search and meta-analysis

BACKGROUND

Invasive pneumococcal disease (IPD) is a major cause of morbidity and mortality globally. However, the literature on the vaccine effectiveness (VE) of 23-valent polysaccharide vaccine (PPV23) and 13-valent conjugated vaccine (PCV13) against IPD in adults is sparse. The aim was to summarize the available evidence on the VE of the PPV23 and the PCV13 in elderly individuals against IPD and to investigate how age and comorbidities influence VE against IPD.

METHODS

A systematic search was conducted in Medline and Embase in February 2021. We used combinations of terms related to PPV23, PCV13, elderly, high-risk populations, and IPD. Eligible articles published since 2010 were included. Two authors reviewed and extracted data.

RESULTS

Eight studies met the inclusion criteria for PPV23. The meta-analysis showed a reduced OR for all-type IPD with the use of PPV23 vaccine compared with unvaccinated controls (OR 0.69; 95%CI 0.54, 0.88) and a reduced OR for vaccine-type IPD compared with non-vaccine type IPD (0.69; 95%CI 0.63, 0.76). VE against vaccine-type IPD ranged from 28% to 54.1% for individuals aged 65-79 and from 7.5% to 34% for those aged ≥80-85 years. Most studies found a lower VE of PPV23 in populations with comorbidities and in immunocompromised populations compared with the VE for individuals without comorbidities.One study met the inclusion criteria for PCV13. The vaccine efficacy of PCV13 against IPD in individuals aged ≥65 was 75.0% (95% CI, 41.4 to 90.8).

CONCLUSION

The results from this review show a reduction of IPD in elderly and high-risk populations vaccinated with PPV23 and PCV13. The protective effect may be lower in elderly individuals aged >80 and in individuals with comorbidities. However, the literature is sparse; large-scale prospective studies are required to evaluate the VE of PPV23 and PCV13 vaccination in adults against IPD.

Serotype distribution and antimicrobial susceptibility of invasive Streptococcus pneumoniae isolates among adult and elderly population before and after introduction of pneumococcal conjugate vaccine in Casablanca, Morocco

BACKGROUND

Streptococcus pneumoniae (S. pneumoniae), remains a major cause of mortality and morbidity worldwide. The objective of this study was to determine the trends of invasive pneumococcal diseases (IPD) in adult and elderly population in Casablanca (Morocco) before and after introduction of pneumococcal conjugate vaccine (PCV) by determining the distribution of pneumococcal serotypes and antibiotic resistance profile of isolated strains.

METHOD

The proposed study is a retrospective laboratory-based surveillance of IPD in hospitalized adult (15-59 years old) and elderly (≥ 60 years old) patients in Ibn Rochd University Hospital Centre from 2007 to 2019 (13 years). All the 250 non-duplicate clinical invasive isolates from adult and elderly patients, confirmed as S. pneumoniae according to the laboratory standard identification procedures, are included in this study.

RESULTS

A significant decrease of the overall incidence in IPD was observed only in adults from 0.71 to 0.54/100000 populations (P  =  0.02) and to 0.47/100000 populations (P  =  0.0137) in the early and mature post-vaccine period respectively compared to the pre-vaccine period. Our results also showed a significant reduction in the overall prevalence of vaccine serotypes from 28.17 to 6.90% (P  =  0.0021) for the PCV-10 serotypes, and from 46.48 to 25.86% (P  =  0.0164) for the PCV-13 serotypes only in the mature post-vaccine period (2015-2019). In parallel, the rate of non-vaccine serotypes did not significantly change in the early post-vaccine period (2011-2014) while it increased considerably from 54 to 74.14% (P  =  0.0189) during the mature post-vaccine period. The rate of penicillin non-susceptible pneumococcal isolates decreased significantly from 23.94 to 8.77% (P  =  0.02) in adult patients, and the rate of cotrimoxazole non-susceptible pneumococcal isolates significantly decreased from 29.58 to 8.77% in the early post-vaccine period (P  =  0.003) and to 7.24% in the mature post-vaccine period (P  =  0.0007).

CONCLUSION

Although childhood vaccination has considerably reduced the incidence of IPD in adult population through the herd effect, IPD remain a real public health problem due to the alarming increase in non-vaccine serotypes (NVS) and the lack of herd effect among elderly population. The rate of antibiotic resistance was relatively low. Nevertheless, resistance constitutes a serious problem to the therapeutic arsenal due to the known capacity for genetic dissemination in the pneumococcus.

Prevalence of Pneumococcal Serotypes in Community-Acquired Pneumonia among Older Adults in Italy: A Multicenter Cohort Study

Pneumococcal community-acquired pneumonia (CAP) is a leading cause of mortality. Following the introduction of pneumococcal conjugate vaccines (PCVs) in children, a decrease in the burden of the disease was reported. In parallel, an increase in non-vaccine serotypes was also noted. The objective of this study was to assess the current serotype-specific epidemiology of pneumococci among Italian older adults hospitalized for CAP. A prospective study was conducted between 2017 and 2020 in four Italian regions. Subjects aged ≥65 years hospitalized with confirmed CAP were tested for pneumococci using both pneumococcal urinary antigen and serotype-specific urine antigen tests able to identify all 24 serotypes included in the available vaccines. Of the 1155 CAP cases, 13.1% were positive for pneumococci. The most prevalent serotypes were 3 (2.0%), 8 (1.7%), 22F (0.8 %) and 11A (0.7%). These serotypes are all included in the newly licensed PCV20. The serotypes included in PCV13, PCV15 and PCV20 contributed to 3.3%, 4.4% and 7.5% of the CAP cases, respectively. In the context of a low PCV13 coverage among older adults and a high PCV coverage in children, a substantial proportion of CAP is caused by PCV13 serotypes. Higher valency PCV15 and PCV20 may provide additional benefits for the prevention of CAP in vaccinated older adults.

30-Minute Highly Multiplexed VaxArray Immunoassay for Pneumococcal Vaccine Antigen Characterization

Pneumonia accounts for over 20% of deaths worldwide in children aged 1 to 5 years, disproportionately affecting lower- and middle-income countries. Effective, highly multivalent pneumococcal vaccines are available to decrease disease burden, with numerous new vaccines currently under development to serve a variety of worldwide markets. However, pneumococcal conjugate vaccines are among the hardest biologics to manufacture and characterize due to their complexity and heterogeneity. Current characterization methods are often inherently singleplex, requiring separate tests for each serotype present. In addition, identity and quantity are often determined with separate methods. We developed the VaxArray pneumococcal assay for applications in identity, quantity, and stability testing of pneumococcal polysaccharide and pneumococcal conjugate vaccines. The VaxArray pneumococcal assay has a time to result of less than 30 min and is an off-the-shelf multiplexed, microarray-based immunoassay kit that can identify and simultaneously quantify 23 pneumococcal polysaccharide serotypes common to many on-market and in-development vaccines. Here, we highlight the potential of the assay for identity testing by showing high reactivity and serotype specificity to a wide variety of native polysaccharides, CRM197-conjugated polysaccharides, and drug product. The assay also has vaccine-relevant lower limits of quantification in the low-to-mid ng/mL range and can be used for accurate quantification even in adjuvanted vaccines. Excellent correlation to the anthrone assay is demonstrated, with VaxArray resulting in significantly improved precision over this antiquated chemical method.

A phase III, multicenter, randomized, double-blind, active comparator-controlled study to evaluate the safety, tolerability, and immunogenicity of catch-up vaccination regimens of V114, a 15-valent pneumococcal conjugate vaccine, in healthy infants, children, and adolescents (PNEU-PLAN)

BACKGROUND

Despite widespread use of pneumococcal conjugate vaccines (PCVs) in children, morbidity and mortality caused by pneumococcal disease (PD) remain high. In addition, many children do not complete their PCV course on schedule. V114 is a 15-valent PCV that contains two epidemiologically important serotypes, 22F and 33F, in addition to the 13 serotypes present in PCV13, the licensed 13-valent PCV.

METHODS

This phase III descriptive study evaluated safety and immunogenicity of catch-up vaccination with V114 or PCV13 in healthy children 7 months-17 years of age who were either pneumococcal vaccine-naïve or previously immunized with lower valency PCVs (NCT03885934). Overall, 606 healthy children were randomized to receive V114 (n = 303) or PCV13 (n = 303) via age-appropriate catch-up vaccination schedules in three age cohorts (7-11 months, 12-23 months, or 2-17 years).

RESULTS

Similar proportions of children 7-11 months and 2-17 years of age reported adverse events (AEs) in the V114 and PCV13 groups. A numerically greater proportion of children 12-23 months of age reported AEs in the V114 group (79.0%) than the PCV13 group (59.4%). The proportions of children who reported serious AEs varied between different age cohorts but were generally comparable between vaccination groups. No vaccine-related serious AEs were reported, and no deaths occurred. At 30 days after the last PCV dose, serotype-specific immunoglobulin G geometric mean concentrations were comparable between vaccination groups for the 13 shared serotypes and higher in the V114 group for 22F and 33F.

CONCLUSIONS

Catch-up vaccination with V114 in healthy individuals 7 months-17 years of age was generally well tolerated and immunogenic for all 15 serotypes, including those not contained in PCV13, regardless of prior pneumococcal vaccination. These results support V114 catch-up vaccination in children with incomplete or no PCV immunization per the recommended schedule.

Parents' attitude towards pneumococcal vaccine: an online survey from Jordan

OBJECTIVES

In developing countries, the pneumococcal conjugate vaccine (PCV) has not been incorporated into the national immunization schedule, and the vaccination rate is low. This study aimed to examine parental knowledge, attitudes, and barriers to children receiving the PCV in Jordan.

METHODS

This was a questionnaire-based cross-sectional study. The online survey was written in Arabic and consisted of three main sections. The questionnaire was distributed via social media platforms, such as Facebook, Twitter, and WhatsApp.

RESULTS

In total, 720 responses were analyzed. Only 149 (20.7%) of the parents' children were vaccinated with the PCV. However, almost half 356 (49.4%) of the respondents were willing to vaccinate their children. Most (563, 78.1%) parents stated that the vaccine would protect their children from pneumococcal disease. More than two thirds (516, 71.6%) of them strongly agreed or agreed that the cost of the PCV is high. Parents who had vaccinated their children had a higher monthly income than parents who had not vaccinated their children.

CONCLUSIONS

This study shows a lack of knowledge regarding pneumococcal infection and the PCV among Jordanian parents. This is the main barrier to vaccinating children. Therefore, improving parental knowledge would increase the rate of vaccination among Jordanian children.

The remarkable history of pneumococcal vaccination: an ongoing challenge

Although it varies with age and geographical distribution, the global burden of infection with Streptococcus pneumoniae (pneumococcus) remains considerable. The elderly, and younger adults with comorbid conditions, are at particularly high risk of pneumococcal infection, and this risk will increase as the population ages. Vaccination should be the backbone of our current strategies to deal with this infection.

Main body: This manuscript reviews the history of the development of pneumococcal vaccines, and the impact of different vaccines and vaccination strategies over the past 111 years. It documents the early years of vaccine development in the gold mines of South Africa, when vaccination with killed pneumococci was shown to be effective, even before the recognition that different pneumococci were antigenically distinct. The development of type-specific vaccines, still with whole killed pneumococci, showed a high degree of efficacy. The identification of the importance of the pneumococcal capsule heralded the era of vaccination with capsular polysaccharides, although with the advent of penicillin, interest in pneumococcal vaccine development waned. The efforts of Austrian and his colleagues, who documented that despite penicillin therapy, patients still died from pneumococcal infection in the first 96 h, ultimately led to the licensing first of a 14-valent pneumococcal polysaccharide in 1977 followed by the 23-valent pneumococcal polysaccharide in 1983. The principal problem with these, as with other polysaccharide vaccines, was that that they failed to immunize infants and toddlers, who were at highest risk for pneumococcal disease. This was overcome by chemical linking or conjugation of the polysaccharide molecules to an immunogenic carrier protein. Thus began the era of pneumococcal conjugate vaccine (PCV), starting with PCV7, progressing to PCV10 and PCV13, and, most recently, PCV15 and PCV20. However, these vaccines remain serotype specific, posing the challenge of new serotypes replacing vaccine types. Current research addresses serotype-independent vaccines which, so far, has been a challenging and elusive endeavor.

Conclusion: While there has been enormous progress in the development of pneumococcal vaccines during the past century, attempts to develop a vaccine that will retain its efficacy for most pneumococcal serotypes are ongoing.

Streptococcus pneumoniae vaccination strategies and its expected impact on penicillin non-susceptibility in children under the age of five: Let's recap!

•

The efficacy of PCVs currently used in children under 5 years of age is threatened by the emergence of invasive and resistant non-vaccine serotypes worldwide.

•

Resistant NVT strains are emerging in IPD in children < 5 years mainly serotypes 24F, 15A, 11A and 33F along with serotype 19A in PCV-10 settings.

•

Continuous surveillance is necessary in IPD in children under five to monitor the long-term effect of PCV-10 and PCV-13 on penicillin resistance trends.

The impact of pneumococcal conjugate vaccines (PCVs) on invasive pneumococcal disease (IPD) burden has been extensively studied in children aged<5 years; however, a pooled estimation of the effect of PCVs on penicillin non-susceptible pneumococci (PNSP) has not yet been performed. We aimed to identify whether the introduction of PCV-10 and PCV-13 had led to the decrease of the overall PNSP rate in children < 5 years. We conducted a systematic review of published surveillance studies reporting the rate of PNSP rates in children < 5 in countries where PCV10/13 were introduced. The overall observed trend onwards the introduction of PCV-10 and PCV-13 is a decrease in PNSP among children < 5 years in surveillance sites located in PCV-13 countries. We identified an increase of PNSP rates (serotype 19A) in PCV-10 settings. Resistant NVT strains are emerging in IPD in children < 5 years mainly serotypes 24F, 15A, 11A and 33F along with serotype 19A in PCV-10 settings. Continuous surveillance is necessary in IPD in children under five to monitor the long-term effect of PCV-10 and PCV-13 on penicillin resistance trends.

Screening for Immunodeficiencies in Children With Invasive Pneumococcal Disease: Six-year Experience From a UK Children's Hospital

BACKGROUND

A previous study showed that investigation of children with invasive pneumococcal disease (IPD) revealed an immunodeficiency in up to 10% of cases. Following this report, we implemented a protocol to investigate children with IPD, to assess the proportion with an immunodeficiency in our setting.

METHODS

We retrospectively identified patients who presented with IPD from January 2015 to November 2020 and collected data from medical records. Immunological investigations included complement C3 and C4 levels, classical and alternative pathway complement function, IgG, IgA and IgM levels, specific IgG levels (H. influenza B, tetanus and pneumococcal serotypes), peripheral blood film, lymphocyte subsets, and CD62L-shedding upon activation with Toll-like receptor-agonists in selected cases.

RESULTS

We identified a total of 68 children with IPD, with a mortality of 6%. Immunological investigations were performed in 51 children. Four children (8%) had abnormal findings that were deemed of clinical significance. Two children had complement deficiencies (Factor I and C2 deficiency), one child had specific antibody deficiency, and another child had low IgM, low NK-cells and poor persistence of serotype-specific anti-pneumococcal IgG concentrations. Of the 17 children with IPD who were not tested for immunodeficiencies, 4 died and four had possible explanations for the infection.

CONCLUSIONS

We identified clinically relevant abnormal immunological findings in 4/51 (8%) of children with IPD. Our results support the recommendation to perform immunological investigations in children with IPD, since this might reveal underlying immunodeficiencies, allowing for necessary preventive measures and close follow-up.

Pneumococcal Carriage in Infants Post-PCV10 Introduction in Pakistan: Results from Serial Cross-Sectional Surveys

The 10-valent pneumococcal vaccine was introduced in Pakistan’s Expanded Program on Immunization (EPI) in 2013 as a 3 + 0 schedule without catchup. We conducted three annual cross-sectional surveys from 2014−2016 to measure vaccine-type (VT) carriage in infants from a rural part of Pakistan. Nasopharyngeal specimens were collected by random sampling of infants from two union councils of Matiari. Samples were then transported to the Infectious Disease Research Laboratory (IDRL) at the Aga Khan University within 6−8 h of collection. Serotypes were established using sequential multiplex PCR. Of the 665 children enrolled across three surveys, 547 were culture-positive for pneumococcus. VT carriage decreased from 21.8% in 2014 to 12.7% in 2016 (p-value for trend <0.001). Those who were not vaccinated or partially vaccinated were found to be at higher risk of carrying a VT serotype ((aOR 2.53, 95% CI 1.39, 4.63 for non-vaccinated) and (aOR 3.35, 95% CI 1.82, 6.16 for partially vaccinated)). On the other hand, being enrolled in the most recent survey was negatively associated with VT carriage (aOR 0.51, 95% CI 0.28, 0.93). We found that PCV10 was effective in decreasing the carriage of vaccine-type serotypes in Pakistani infants.

Validation of Fourier Transform Infrared Spectroscopy for Serotyping of Streptococcus pneumoniae

Fourier transform infrared (FT-IR) spectroscopy (IR Biotyper; Bruker) allows highly discriminatory fingerprinting of closely related bacterial strains. In this study, FT-IR spectroscopy-based capsular typing of Streptococcus pneumoniae was validated as a rapid, cost-effective, and medium-throughput alternative to the classical phenotypic techniques. A training set of 233 strains was defined, comprising 34 different serotypes and including all 24 vaccine types (VTs) and 10 non-vaccine types (NVTs). The acquired spectra were used to (i) create a dendrogram where strains clustered together according to their serotypes and (ii) train an artificial neural network (ANN) model to predict unknown pneumococcal serotypes. During validation using 153 additional strains, we reached 98.0% accuracy for determining serotypes represented in the training set. Next, the performance of the IR Biotyper was assessed using 124 strains representing 59 non-training set serotypes. In this setting, 42 of 59 serotypes (71.1%) could be accurately categorized as being non-training set serotypes. Furthermore, it was observed that comparability of spectra was affected by the source of the Columbia medium used to grow the pneumococci and that this complicated the robustness and standardization potential of FT-IR spectroscopy. A rigorous laboratory workflow in combination with specific ANN models that account for environmental noise parameters can be applied to overcome this issue in the near future. The IR Biotyper has the potential to be used as a fast, cost-effective, and accurate phenotypic serotyping tool for S. pneumoniae.

Missed Pneumococcal Vaccination Opportunities in Adults With Invasive Pneumococcal Disease in a Community Health System

Background

Adult vaccination programs are suboptimal.

Methods

Pneumococcal vaccination history, and healthcare contact were assessed in patients with invasive pneumococcal disease.

Results

Of the 229 cases, 14% were vaccinated. Observed mortality was 20.1%.

Conclusions

Numerous missed vaccination opportunities were identified.

Treatment outcomes of secondary bacteraemia in patients treated with ceftaroline fosamil: pooled results from six phase III clinical trials

OBJECTIVES

This exploratory pooled analysis assessed the efficacy and safety of ceftaroline fosamil and comparators across six phase III clinical trials in adults with community-acquired pneumonia (CAP) or complicated skin and soft-tissue infection (cSSTI) and secondary bacteraemia.

METHODS

In each trial, FOCUS 1 and 2 (CAP), Asia CAP trial, CANVAS 1 and 2 (cSSTI) and COVERS (cSSTI), patients were randomised to ceftaroline fosamil [600 mg q12h by 1-h i.v. infusion, except in COVERS (600 mg q8h by 2-h i.v. infusion), adjusted for renal function] or comparator. Efficacy assessments included clinical and microbiological responses at test-of-cure visit [microbiological modified intent-to-treat (mMITT) population]. Safety outcomes were assessed.

RESULTS

The pooled mMITT population comprised 1976 patients, of whom 138 had baseline bacteraemia (ceftaroline fosamil, n = 72; comparator, n = 66). Predominant baseline blood pathogens were Staphylococcus aureus (n = 29), Streptococcus pneumoniae (n = 19) and other streptococci (n = 12). Clinical cure rates in bacteraemic patients were 55/72 (76.4%) and 51/66 (77.3%) for ceftaroline fosamil and comparators, respectively, and in non-bacteraemic patients were 822/966 (85.1%) and 717/872 (82.2%). Favourable microbiological response rates in bacteraemic patients were 56/72 (77.8%) for ceftaroline fosamil and 54/66 (81.8%) for comparators, and in non-bacteraemic patients were 825/966 (85.4%) and 719/872 (82.5%). Adverse events in bacteraemic patients were consistent with the known ceftaroline fosamil safety profile or the underlying indications.

CONCLUSION

These pooled clinical and microbiological efficacy data demonstrate generally favourable outcomes for ceftaroline fosamil in patients with CAP or cSSTI and secondary bacteraemia. [Trial Registration: NCT00621504, NCT00509106; NCT01371838; NCT00424190, NCT00423657; NCT01499277].

Systematic review of the efficacy, effectiveness and impact of high-valency pneumococcal conjugate vaccines on otitis media

Otitis media (OM) is a common disease of childhood and available pneumococcal conjugate vaccines (PCVs), with different compositions, could have different impact on OM reduction. This systematic literature review evaluated available data describing the efficacy, effectiveness, and impact of 10-valent pneumococcal Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) and 13-valent PCV (PCV13) on OM outcomes. Statistically significant reductions in all-cause and complicated OM, tympanostomy tube placement and OM-related hospitalizations were consistently observed after the introduction of PHiD-CV and PCV13. Impact studies with data in children <2 years of age using PCV13 report 47–51% and PHiD-CV 34–43% reduction of all-cause OM (primary care, outpatient, ambulatory, emergency department visits) compared to periods before PCV introduction. When the impact of both vaccines is assessed in comparable settings, some studies suggest PHiD-CV may offer better protection against some OM outcomes. Well-designed, head-to-head comparisons are needed to better understand the differences and guide vaccination policies.

What is the context?

Pneumococcal vaccines are highly effective in preventing pneumonia and meningitis in children. The two main pneumococcal vaccines are PHiD-CV (Synflorix, GSK) and PCV13 (Prevenar 13, Pfizer). Both vaccines have been shown to provide protection against otitis media despite differing in their composition.

However, it is currently unknown if both vaccines confer similar level of protection against otitis media.

What is new?

We conducted a literature review to evaluate the effects of PHiD-CV and PCV13 on otitis media.

From 33 articles, we found that:

‡Both vaccines were effective in reducing doctor visits for otitis media as well as the number of severe cases and cases requiring hospitalization.

‡Four studies suggested a higher level of protection provided by PHiD-CV compared to PCV13, although more data is needed to confirm this finding.

What is the impact?

Available information shows that PHiD-CV and PCV13 are effective in preventing a proportion of otitis media during childhood.

Given the remaining substantial burden associated with the disease and the related significant usage of antibiotics, the development of improved vaccines with higher impact on otitis media would be welcome.

BIGDATA: A Protocol to Create and Extend a 25-Year Clinical Trial and Observational Data Asset to Address Key Knowledge Gaps in Otitis Media and Hearing Loss in Australian Aboriginal and Non-Aboriginal Children

INTRODUCTION

Otitis media (OM) is a common childhood illness, often resolving without intervention and acute and long-term complications are rare. However, Australian Aboriginal and Torres Strait Islander infants and children experience a high burden of OM and are at high risk of complications (tympanic membrane perforation and chronic infections). Bacterial OM is commonly associated with Streptococcus pneumoniae, non-typeable Haemophilus influenzae, and Moraxella catarrhalis. BIGDATA is a data asset combining over 25 years of microbiology and OM surveillance research from the Ear Health Research Program at Menzies School of Health Research (Northern Territory, Australia), including 11 randomized controlled trials, four cohort studies, eight surveys in over 30 remote communities (including data from Western Australia), and five surveys of urban childcare centers including Aboriginal and Torres Strait Islander and non-Indigenous children. Outcome measures include clinical examinations (focusing on OM), antibiotic prescriptions, pneumococcal vaccination, modifiable risk factors such as smoking and household crowding, and nasopharyngeal and ear discharge microbiology including antimicrobial resistance testing.

METHODS AND ANALYSIS

The initial series of projects are planned to address the following key knowledge gaps: (i) otitis media prevalence and severity over pre pneumococcal conjugate vaccines (PCVs) and three eras of increasing PCV valency; (ii) impact of increasing valency PCVs on nasopharyngeal carriage dynamics of pneumococcal serotypes, and antimicrobial resistance; (iii) impact of increasing valency PCVs on nasopharyngeal carriage dynamics and antimicrobial resistance of other otopathogens; and (iv) serotype specific differences between children with acute OM and OM with effusion or without OM. These data will be utilized to identify research gaps, providing evidence-based prioritization for ongoing research.

ETHICS AND DISSEMINATION

Data asset creation and priority analyses were approved by the Human Research Ethics Committee of Northern Territory Department of Health and Menzies School of Health Research (EC00153, 18-3281), the Child and Adolescent Health Service Human Research Ethics Committee and Western Australian Aboriginal Health Ethics Committee. Dissemination will be through peer review publication and conference presentations.

Serotype Replacement after Introduction of 10-Valent and 13-Valent Pneumococcal Conjugate Vaccines in 10 Countries, Europe

We evaluated invasive pneumococcal disease (IPD) during 8 years of infant pneumococcal conjugate vaccine (PCV) programs using 10-valent (PCV10) and 13-valent (PCV13) vaccines in 10 countries in Europe. IPD incidence declined during 2011-2014 but increased during 2015-2018 in all age groups. From the 7-valent PCV period to 2018, IPD incidence declined by 42% in children <5 years of age, 32% in persons 5-64 years of age, and 7% in persons >65 years of age; non-PCV13 serotype incidence increased by 111%, 63%, and 84%, respectively, for these groups. Trends were similar in countries using PCV13 or PCV10, despite different serotype distribution. In 2018, serotypes in the 15-valent and 20-valent PCVs represented one third of cases in children <5 years of age and two thirds of cases in persons >65 years of age. Non-PCV13 serotype increases reduced the overall effect of childhood PCV10/PCV13 programs on IPD. New vaccines providing broader serotype protection are needed.

Systematic literature review of the disease burden and vaccination of pneumococcal disease among adults in select Asia-Pacific areas

INTRODUCTION

Pneumococcal diseases are common and cause significant morbidity and mortality, with higher rates especially in developing areas including many in the Asia-Pacific (AP) region. However, current strategies to prevent pneumococcal disease in adults are quite complicated and not well implemented among many AP areas, and vaccination coverage rates among adults are generally low or perceived as low in the region. Thus, this literature review's purpose was to summarize the disease burden and vaccination against pneumococcal diseases among adults in select AP areas (Australia, Hong Kong, India, Indonesia, South Korea, Malaysia, New Zealand, the Philippines, Singapore, Taiwan, Thailand, and Vietnam).

AREAS COVERED

This systematic review included published articles from January 2010 to August 2020 using MEDLINE/Embase. Grey literature websites were searched for national immunization programs and medical society vaccination recommendations from areas of interest. A total of 69 publications were identified.

EXPERT OPINION

In the AP region, pneumococcal disease burden and serotype prevalence are variable among adult populations, particularly among older adults. Data was provided primarily from countries with established national immunization programs (NIPs). Further research on the disease burden and emphasis on the benefits of vaccination in AP areas lacking pneumococcal vaccination programs is warranted.

Minimally Invasive Tissue Sampling: A Tool to Guide Efforts to Reduce AIDS-Related Mortality in Resource-Limited Settings

BACKGROUND

Available information on the causes of death among people living with human immunodeficiency virus (PLHIV) in low- and middle-income countries (LMICs) remains scarce. We aimed to provide data on causes of death in PLHIV from two LMICs, Brazil and Mozambique, to assess the impact of clinical misdiagnosis on mortality rates and to evaluate the accuracy of minimally invasive tissue sampling (MITS) in determining the cause of death in PLHIV.

METHODS

We performed coupled MITS and complete autopsy on 164 deceased PLHIV (18 children, 36 maternal deaths, and 110 adults). HIV antibody levels and HIV RNA viral loads were determined from postmortem serum samples.

RESULTS

Tuberculosis (22.7%), toxoplasmosis (13.9%), bacterial infections (13.9%), and cryptococcosis (10.9%) were the leading causes of death in adults. In maternal deaths, tuberculosis (13.9%), bacterial infections (13.9%), cryptococcosis (11.1%), and cerebral malaria (8.3%) were the most frequent infections, whereas viral infections, particularly cytomegalovirus (38.9%), bacterial infections (27.8%), pneumocystosis (11.1%), and HIV-associated malignant neoplasms (11.1%) were the leading cause among children. Agreement between the MITS and the complete autopsy was 100% in children, 91% in adults, and 78% in maternal deaths. The MITS correctly identified the microorganism causing death in 89% of cases.

CONCLUSIONS

Postmortem studies provide highly granular data on the causes of death in PLHIV. The inaccuracy of clinical diagnosis may play a significant role in the high mortality rates observed among PLHIV in LMICs. MITS might be helpful in monitoring the causes of death in PLHIV and in highlighting the gaps in the management of the infections.

A systematic review of invasive pneumococcal disease vaccine failures and breakthrough with higher-valency pneumococcal conjugate vaccines in children

INTRODUCTION

: The pneumococcal non-typeable Haemophilus influenzae protein D-conjugate vaccine (PHiD-CV or PCV10) and 13-valent pneumococcal conjugate vaccine (PCV13) protect against vaccine-serotype invasive pneumococcal disease (VT IPD). However, VT IPD can still occur in fully or partially vaccinated children (vaccine failure or breakthrough). We performed a systematic review of vaccine failures and breakthrough IPD with PCV10 and PCV13 in ≤5-year-olds.

AREAS COVERED

: We searched Scopus/Medline/EMBASE to retrieve articles/abstracts published between 1/2008-7/2019. We excluded reports from studies only including data from adults or children ≥6 years, exclusively assessing PCV7-vaccinated children or children with underlying comorbidities. Twenty-six reports (20 PCV13, 1 PCV10, 5 both), covering studies with various designs in six continents, using different schedules, were included. Collectively, these studies reported 469 VT IPD cases classified as vaccine failures and 403 as breakthrough. Vaccine failure and breakthrough rates were low: 8.4% and 9.3%, respectively, of all IPD in vaccinated children, consistent with the vaccines' high effectiveness. The main serotypes associated with vaccine failure or breakthrough were 19A, 3 and 19F in PCV13 studies and 14, 6B and vaccine-related 19A and 6A in PCV10 studies.

EXPERT OPINION

: As we move to vaccines with more serotypes, it is not only important to consider which serotypes are added, but also to monitor and address incomplete protection against specific serotypes.

Cytokine response in cerebrospinal fluid of meningitis patients and outcome associated with pneumococcal serotype

Streptococcus pneumoniae causes life-threatening meningitis. Its capsular polysaccharide determines the serotype and influences disease severity but the mechanism is largely unknown. Due to evidence of elevated cytokines levels in the meningeal inflammatory response, we measured 41 cytokines/chemokines and growth factors in cerebrospinal fluid (CSF) samples from 57 South African meningitis patients (collected in the period 2018–2019), with confirmed S. pneumoniae serotypes, using a multiplexed bead-based immunoassay. Based on multivariable Bayesian regression, using serotype 10A as a reference and after adjusting for HIV and age, we found IL-6 concentrations significantly lower in patients infected with serotypes 6D (undetectable) and 23A (1601 pg/ml), IL-8 concentrations significantly higher in those infected with 22A (40,459 pg/ml), 7F (32,400 pg/ml) and 15B/C (6845 pg/ml), and TNFα concentration significantly higher in those infected with serotype 18A (33,097 pg/ml). Although a relatively small number of clinical samples were available for this study and 28% of samples could not be assigned to a definitive serotype, our data suggests 15B/C worthy of monitoring during surveillance as it is associated with in-hospital case fatality and not included in the 13-valent polysaccharide conjugate vaccine, PCV13. Our data provides average CSF concentrations of a range of cytokines and growth factors for 18 different serotypes (14, 19F, 3, 6A, 7F, 19A, 8, 9N, 10A, 12F, 15B/C, 22F, 16F, 23A, 31, 18A, 6D, 22A) to serve as a basis for future studies investigating host–pathogen interaction during pneumococcal meningitis. We note that differences in induction of IL-8 between serotypes may be particularly worthy of future study.

Impact of national introduction of ten-valent pneumococcal conjugate vaccine on invasive pneumococcal disease in Bangladesh: Case-control and time-trend studies

BACKGROUND

Bangladesh introduced the ten-valent pneumococcal conjugate vaccine (PCV10) into its national immunization program in March 2015 creating an opportunity to assess the real-world impact of PCV on invasive pneumococcal disease (IPD).

METHODS

Between January 2014 and June 2018, children aged 3-35 months in three rural sub-districts of Sylhet district of Bangladesh were visited every two months to collect morbidity and care-seeking data. Children attending sub-district hospitals with pneumonia, meningitis, or sepsis were assessed for IPD after obtaining informed consent. Blood and cerebrospinal fluid were collected from enrolled children to isolate pneumococcus using culture and molecular test. Children who were age-eligible to receive the PCV and had pneumococcus isolated were enrolled as cases. Four age and sex-matched clinic and community controls were selected for each case within one to two weeks of case identification. Data on immunization status and confounders were collected. PCV coverage was estimated using vaccine coverage surveys. Case-control and incidence trend analyses were conducted to assess the impact of PCV on IPD.

RESULTS

The community cohort yielded 217,605 child years of observations and 154,773 sick child-visits to study hospitals. Pneumococcus was isolated from 44 children who were age-eligible to receive PCV; these children were enrolled as cases. The cases were matched with 166 community- and 150 clinic-controls. The matched case-control analyses using community-controls showed 83% effectiveness (95% CI: 1.57-97.1%) and clinic controls showed 90% effectiveness (95% CI: -26.0% to 99.1%) of PCV in preventing IPD. Incidence trend analysis estimated vaccine effectiveness at 80.1% (95% CI: 38.4, 93.6).

CONCLUSION

PCV in this pediatric population in Bangladesh was highly effective in preventing IPD.

Aetiology of acute respiratory infection in preschool children requiring hospitalisation in Europe-results from the PED-MERMAIDS multicentre case-control study

Background

Both pathogenic bacteria and viruses are frequently detected in the nasopharynx (NP) of children in the absence of acute respiratory infection (ARI) symptoms. The aim of this study was to estimate the aetiological fractions for ARI hospitalisation in children for respiratory syncytial virus (RSV) and influenza virus and to determine whether detection of specific respiratory pathogens on NP samples was associated with ARI hospitalisation.

Methods

349 children up to 5 years of age hospitalised for ARI (following a symptom-based case definition) and 306 hospital controls were prospectively enrolled in 16 centres across seven European Union countries between 2016 and 2019. Admission day NP swabs were analysed by multiplex PCR for 25 targets.

Results

RSV was the leading single cause of ARI hospitalisations, with an overall population attributable fraction (PAF) of 33.4% and high seasonality as well as preponderance in younger children. Detection of RSV on NP swabs was strongly associated with ARI hospitalisation (OR adjusted for age and season: 20.6, 95% CI: 9.4 to 45.3). Detection of three other viral pathogens showed strong associations with ARI hospitalisation: influenza viruses had an adjusted OR of 6.1 (95% CI: 2.5 to 14.9), parainfluenza viruses (PIVs) an adjusted OR of 4.6 (95% CI: 1.8 to 11.3) and metapneumoviruses an adjusted OR of 4.5 (95% CI: 1.3 to 16.1). Influenza viruses had a PAF of 7.9%, PIVs of 6.5% and metapneumoviruses of 3.0%. In contrast, most other pathogens were found in similar proportions in cases and controls, including Streptococcus pneumoniae, which was weakly associated with case status, and endemic coronaviruses.

Conclusion

RSV is the predominant cause of ARI hospitalisations in young children in Europe and its detection, as well as detection of influenza virus, PIV or metapneumovirus, on NP swabs can establish aetiology with high probability. PAFs for RSV and influenza virus are highly seasonal and age dependent.

Serotype distribution of invasive, non-invasive and carried Streptococcus pneumoniae in Malaysia: a meta-analysis

Background

Pneumococcal pneumonia is the leading cause of under-five mortality globally. The surveillance of pneumococcal serotypes is therefore vital for informing pneumococcal vaccination policy and programmes. Pneumococcal conjugate vaccines (PCVs) have been available as an option in the private healthcare setting and beginning December 2020, PCV10 was incorporated as part of routine national immunisation programme (NIP) in Malaysia. We searched existing literature on pneumococcal serotype distribution across Malaysia to provide an overall view of this distribution before the implementation of PCV10.

Methods

Online databases (PubMed, Ovid MEDLINE and Scopus), reference lists of articles identified, and grey literature (Malaysian Ministry of Health website, WHO website) were systematically searched for relevant literature on pneumococcal serotype distribution across Malaysia up to 10th November 2020. No lower date limit was set to maximise the number of target reports returned. Results of serotypes were split by age categories, including ≤5 years, > 5 years and unreported for those that did not specify.

Results

The search returned 18 relevant results, with a total of 2040 isolates. The most common serotypes across all disease types were 19F (n = 313, 15.3% [95%CI: 13.8–17.0]), 23F (n = 166, 8.1% [95%CI: 7.0–9.4]), 14 (n = 166, 8.1% [95%CI: 7.0–9.4]), 6B (n = 163, 8.0% [95%CI: 6.9–9.2]) and 19A (n = 138, 6.8% [95%CI: 5.8–7.9]).

Conclusion

Four of the most common serotypes across all isolate sources in Malaysia are covered by PCV10, while PCV13 provides greater serotype coverage in comparison to PCV10. There is still a need for surveillance studies, particularly those investigating serotypes in children under 5 years of age, to monitor vaccine effectiveness and pneumococcal population dynamic following implementation of PCV10 into routine immunisation.

Nasopharyngeal Microbiota Profiles in Rural Venezuelan Children Are Associated With Respiratory and Gastrointestinal Infections

Background

Recent research suggests that the microbiota affects susceptibility to both respiratory tract infections (RTIs) and gastrointestinal infections (GIIs). In order to optimize global treatment options, it is important to characterize microbiota profiles across different niches and geographic/socioeconomic areas where RTI and GII prevalences are high.

Methods

We performed 16S sequencing of nasopharyngeal swabs from 209 Venezuelan Amerindian children aged 6 weeks–59 months who were participating in a 13-valent pneumococcal conjugate vaccine (PCV13) study. Using random forest models, differential abundance testing, and regression analysis, we determined whether specific bacteria were associated with RTIs or GIIs and variation in PCV13 response.

Results

Microbiota compositions differed between children with or without RTIs (P = .018) or GIIs (P = .001). Several species were associated with the absence of infections. Some of these health-associated bacteria are also observed in developed regions, such as Corynebacterium (log2(fold change [FC]) = 3.30 for RTIs and log2(FC) = 1.71 for GIIs), while others are not commonly observed in developed regions, such as Acinetobacter (log2(FC) = 2.82 and log2(FC) = 5.06, respectively). Klebsiella spp. presence was associated with both RTIs (log2(FC) = 5.48) and GIIs (log2(FC) = 7.20).

Conclusions

The nasopharyngeal microbiota of rural Venezuelan children included several bacteria that thrive in tropical humid climates. Interestingly, nasopharyngeal microbiota composition not only differed in children with an RTI but also in those with a GII, which suggests a reciprocal interplay between the 2 environments. Knowledge of region-specific microbiota patterns enables tailoring of preventive and therapeutic approaches.

The incremental burden of invasive pneumococcal disease associated with a decline in childhood vaccination using a dynamic transmission model in Japan: A secondary impact of COVID-19

The coronavirus disease 2019 (COVID-19) pandemic has disrupted childhood vaccinations, including pneumococcal conjugate vaccine (PCV). Evaluating the possible impact on the invasive pneumococcal disease (IPD) incidence associated with a decline in childhood pneumococcal vaccination is important to advocate the PCV programs. Using a deterministic, dynamic transmission model, the differential incidence and burden of IPD in children younger than 5 years in Japan were estimated between the rapid vaccination recovery (January 2021) and the delayed vaccination recovery (April 2022) scenarios for the next 10 years. In our model, the IPD incidence was reduced from 11.9/100,000 in 2019 to 6.3/100,000 in 2020, caused by a reduced transmission rate due to the COVID-19 mitigation measures. Assuming a recovery in the transmission rate in 2022 April, the incidence of IPD was estimated to increase with maximal incidence of 12.1 and 13.1/100,000 children under 5 years in the rapid and the delayed vaccination recovery scenarios. The difference in the total IPD incidence between these two scenarios was primarily driven by vaccine serotypes IPD incidence. The difference of incidence was not observed between the two scenarios after 2025. The persistent decline in childhood pneumococcal vaccination rates due to the impact of COVID-19 might lead to an increased IPD incidence and an incremental disease burden.

Pneumonia and Invasive Pneumococcal Diseases: The Role of Pneumococcal Conjugate Vaccine in the Era of Multi-Drug Resistance

Streptococcus pneumoniae related diseases are a leading cause of morbidity and mortality, especially in children and in the elderly population. It is transmitted to other individuals through droplets and it can spread to other parts of the human host, causing a wide spectrum of clinical syndromes, affecting between 10 and 100 cases per 100,000 people in Europe and the USA. In order to reduce morbidity and mortality caused by this agent, pneumococcal vaccines have been developed over the years and have shown incredible effectiveness in reducing the spread of this bacterium and the development of related diseases, obtaining a significant reduction in mortality, especially in developing countries. However, considerable problems are emerging mainly due to the replacement phenomenon, multi-drug resistance, and the high production costs of conjugated vaccines. There is still a debate about the indications given by various countries to different age groups; this is one of the reasons for the diffusion of different serotypes. To cope with these problems, significant efforts have been made in the research field to further improve vaccination serotypes coverage. On the other hand, an equally important commitment by health care systems to all age group populations is needed to improve vaccination coverage.

Impact after 10-year use of pneumococcal conjugate vaccine in the Brazilian national immunization program: an updated systematic literature review from 2015 to 2020

In 2010, a 10-valent pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) was introduced in the Brazilian national immunization program; the 3 + 1 dose schedule was replaced by a 2 + 1 dose schedule in 2016. This systematic review presents the latest published evidence (2015–2020) on the impact after 10-year use of PHiD-CV in Brazil from a total of 29 publications. Overall, the PHiD-CV program had a positive impact on the morbidity and mortality associated with invasive pneumococcal disease (IPD), pneumonia and acute otitis media (AOM) in children <5 years-old. A reduction in the vaccine-type invasive disease was observed in all-ages; suggesting indirect protection unvaccinated older children and adults. The occurrence of non-vaccine type disease was evidenced in some studies. Higher vaccination coverage is required at national and state level for sustained population impact. Given the change in the vaccination schedule and the dynamics of pneumococcal disease epidemiology, continuous surveillance is warranted.

GSK Study identifier: HO-18-19438

Exploring the evidence behind the comparable impact of the pneumococcal conjugate vaccines PHiD-CV and PCV13 on overall pneumococcal disease

The worldwide implementation of pneumococcal conjugate vaccines (PCVs) in children has reduced the overall pneumococcal disease burden. Two PCVs are widely available for infant vaccination: the pneumococcal non-typeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV) and the 13-valent PCV (PCV13). While these PCVs differ in serotype composition (PCV13 includes polysaccharides of serotypes 3, 6A and 19A; PHiD-CV does not), their impact on the overall pneumococcal disease burden in children is comparable. This commentary summarizes the evidence of comparability between PHiD-CV and PCV13 and explores why differences in serotype composition may not necessarily translate into a differential clinical impact. Both vaccines confer similarly high protection against disease caused by vaccine serotypes and lead to a partial replacement by non-vaccine serotypes. PHiD-CV does not protect against serotype 3 disease (not included in the vaccine) and PCV13’s effect on this serotype has been inconsistent. PHiD-CV provides some cross-protection against disease caused by vaccine-related serotype 19A but neither vaccine has fully controlled 19A disease. While protection against 19A is higher for PCV13 than PHiD-CV, replacement by non-PCV13 serotypes in settings with a PCV13 program appears to compensate for this difference. This results in a similar residual overall disease burden with both vaccines.

What is the context?

The pneumococcus bacterium can cause infections of the meninges, blood, lung, middle ear and sinuses.

Two vaccins, Synflorix (GSK) and Prevnar 13 (Pfizer Inc.), are widely used to protect young children against these infections.

The vaccines’ compositions differ: Synflorix includes antigens from 10 pneumococcus strains (or “serotypes”) and Prevnar 13 from 13 serotypes.

However, both have a similar effect on the total pneumococcal disease burden in children.

What does this commentary highlight?

This commentary summarizes the evidence beihnd the two vaccines’ comparable impact on pneumococcal disase.

It also looks at why the vaccines have a similar effect on the total pneumococcal disease burden despite their different compositions.

What is the impact on current thinking?

Given that Synflorix and Prevnar 13 have a comparable impact on pneumococcal disease, a country’s choice between the two vaccines will depend on vaccine supply, cost, logistical factors (e.g., transport, storage, training requirements of health workers) and the local pneumococcal epidemiology.

CIRCULATING CLONAL COMPLEXES AND SEQUENCE TYPES OF STREPTOCOCCUS PNEUMONIAE SEROTYPE 19A WORLDWIDE: THE IMPORTANCE OF MULTIDRUG RESISTANCE: A SYSTEMATIC LITERATURE REVIEW

INTRODUCTION

Streptococcus pneumoniae is a major cause of morbidity and mortality, especially amongst young children and the elderly. Childhood implementation of pneumococcal conjugate vaccines (PCVs) significantly reduced the incidence of invasive pneumococcal disease (IPD), while several nonvaccine serotypes remained substantial. Although there is evidence of the impact of higher-valent PCVs on serotype 19A, 19A IPD burden and antibiotic resistance remain a major concern post-vaccination.

AREAS COVERED

We performed a systematic literature review to analyze the frequency and clonal distribution of serotype 19A isolates in the pre- and post-PCV era worldwide providing a scientific background on the factors that influence multidrug resistance in pneumococcal isolates.

EXPERT COMMENTARY

Serotype 19A IPD incidence increased in all regions following the introduction of the 7-valent PCV. The higher-valent PCVs have reduced the rates of 19A IPD isolates, but several circulating strains with diverse antibiotic resistance prevailed. Heterogeneous clonal distribution in serotype 19A was observed within countries and regions, irrespective of higher-valent PCV used. An increase of 19A isolates from pre- to post-vaccination periods were associated with frequently occurring serotype switching events and with the prevalence of multidrug resistant strains. Rational antibiotic policies must be implemented to control the emergence of resistance.Plain Language SummaryWhat is the context?Streptococcus pneumoniae is a major cause of pneumococcal diseases especially amongst young children and the elderly. Vaccination with pneumococcal conjugate vaccines has significantly reduced the incidence of invasive pneumococcal disease worldwide. However, the invasive pneumococcal disease remains an important health problem due to the increase of nonvaccine serotypes. Serotype 19A is predominant in many countries worldwide. Factors contributing to its prevalence include serotype replacement, the emergence of clones with multidrug resistance due to antibiotic overuse, and potential bacteria adaptation in response to the vaccine.What is new?We performed a systematic literature review to 1) analyze the incidence and clonal distribution of serotype 19A isolates pre- and post-vaccination worldwide, and to collect data evaluating antimicrobial resistance patterns displayed by the clones of serotype 19A. We found that 1) clonal distribution in serotype 19A was heterogeneous within countries and regions, irrespective of the vaccine used; 2) the diversity of 19A isolates increased after vaccination. It was associated with frequent serotype switching events and with the prevalence of multidrug resistant strains.What is the impact?Implementation of policies to educate on sustainable antibiotic use and infectious prevention measures may help control the emergence of antibiotic resistance. High-quality active surveillance and future molecular epidemiology studies are needed to understand rapid genetic changes.

Pneumococcal Conjugate Vaccine Impact on Serotype 3: A Review of Surveillance Data

Introduction

Limited changes in serotype 3 invasive pneumococcal disease (IPD) incidence rates after a decade of 13-valent pneumococcal conjugate vaccine (PCV13) introduction into several national immunization programs (NIP) have raised questions about PCV13's effectiveness against this serotype.

Methods

We analyzed the impact of pediatric PCV programs on serotype 3 IPD with two approaches. First, we reviewed the publicly available surveillance data from countries identified in two recently published reviews to describe the population impact of pediatric PCV13 or PCV10 vaccination programs on serotype 3 IPD. We then compared the observed trends in PCV10 and PCV13 countries to a previously described dynamic transmission model that simulates the spread of pneumococcal carriage and development of IPD in a population over time.

Results

When serotype 3 disease rates are compared from countries that have introduced either a 10-valent (PCV10) vaccine that does not contain serotype 3 in its formulation or PCV13 in their pediatric NIP, over time, serotype 3 incidence rate trends are markedly different. Countries with a PCV10 NIP showed a substantial linear increase in serotype 3 pneumococcal disease among all age groups since the time of PCV10 introduction, whereas countries with a PCV13 NIP experienced a modest decline during the 3–4 years after vaccine introduction followed by an inflection upward in subsequent years.

Conclusion

These data suggest that PCV13 provides a certain degree of direct and indirect protection against serotype 3 at the population level and direct adult vaccination with a serotype 3-containing vaccine is likely to provide substantial benefit in the context of a pediatric PCV NIP. Further research around serotype 3 transmission patterns and epidemiology is nonetheless warranted.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40121-021-00406-w.

Live attenuated Bordetella pertussis vaccine candidate BPZE1 transiently protects against lethal pneumococcal disease in mice

BPZE1 is a live attenuated vaccine against infection by Bordetella pertussis, the causative agent of whooping cough. It was previously shown that BPZE1 provides heterologous protection in mouse models of disease caused by unrelated pathogens, such as influenza virus and respiratory syncytial virus. Protection was also observed in mouse models of asthma and contact dermatitis. In this study, we demonstrate that BPZE1 also displays protection against an unrelated bacterial pathogen in a mouse model of invasive pneumococcal disease mediated by Streptococcus pneumoniae. While a single administration of BPZE1 provided no protection, two doses of 10⁶ colony-forming units of BPZE1 given in a three-week interval protected against mortality, lung colonization and dissemination in both BALB/c and C57BL/6 mice. Unlike for the previously reported influenza challenge model, protection was short-lived, and waned within days after booster vaccination. Formaldehyde-killed BPZE1 protected only when administered following a live prime, indicating that priming requires live BPZE1 for protection. Protection against mortality was directly linked to substantially decreased bacterial dissemination in the blood and was lost in MyD88 knock-out mice, demonstrating the role of the innate immune system in the mechanism of protection. This is the first report on a heterologous protective effect of the live BPZE1 vaccine candidate against an unrelated bacterial infection.

Whole genomic comparative analysis of Streptococcus pneumoniae serotype 1 isolates causing invasive and non-invasive infections among children under 5 years in Casablanca, Morocco

BACKGROUND

Streptococcus pneumoniae serotype 1 remains a leading cause of invasive pneumococcal diseases, even in countries with PCV-10/PCV-13 vaccine implementation. The main objective of this study, which is part of the Pneumococcal African Genome project (PAGe), was to determine the phylogenetic relationships of serotype 1 isolates recovered from children patients in Casablanca (Morocco), compared to these from other African countries; and to investigate the contribution of accessory genes and recombination events to the genetic diversity of this serotype.

RESULTS

The genome average size of the six-pneumococcus serotype 1 from Casablanca was 2,227,119 bp, and the average content of coding sequences was 2113, ranging from 2041 to 2161. Pangenome analysis of the 80 genomes used in this study revealed 1685 core genes and 1805 accessory genes. The phylogenetic tree based on core genes and the hierarchical bayesian clustering analysis revealed five sublineages with a phylogeographic structure by country. The Moroccan strains cluster in two different lineages, the five invasive strains clusters altogether in a divergent clade distantly related to the non-invasive strain, that cluster with all the serotype 1 genomes from Africa.

CONCLUSIONS

The whole genome sequencing provides increased resolution analysis of the highly virulent serotype 1 in Casablanca, Morocco. Our results are concordant with previous works, showing that the phylogeography of S. pneumoniae serotype 1 is structured by country, and despite the small size (six isolates) of the Moroccan sample, our analysis shows the genetic cohesion of the Moroccan invasive isolates.

Invasive Pneumococcal Disease in Latvia in PCV10 Vaccination Era, 2012-2018

In 2010 in Latvia, invasive pneumococcal disease (IPD) became a cause for concern and vaccination of infants with four doses of 7-valent pneumococcal conjugate vaccine (PCV7) commenced. In 2012, 10-valent pneumococcal conjugate vaccine (PCV10) (three doses at 2, 4, and 12-15 month of age) vaccination was introduced. We described incidence and serotype distribution of IPD in Latvia and investigated serotypes associated with death from IPD based on surveillance data. Adult vaccination against pneumococcal infection is not included in the national immunization program. Laboratory confirmed IPD cases are passively notified to the Center for Disease Prevention and Control of Latvia (CDPC) by laboratories and clinicians. We calculated incidence by age, sex, case fatality, and trend in serotypes by conducting a retrospective population-based cross-sectional study based on national IPD surveillance data. From 2012 to 2018 466 cases of IPD were reported. The highest notified incidence was in 2015 at 4.4/100,000, which fell to 3.9 in 2018. The highest mean annual IPD incidence was in infants (4.8) and in the elderly (6.0). PCV10 vaccine serotypes were the most prevalent in IPD cases up to 2015 with a decreasing trend from 50% (20/40) in 2012 to 19% (14/74) in 2018 (chi2 test for trend of odds = 0.000). PCV23nonPCV13 vaccine serotypes had an increasing trend and rose from 18% (7/40) to 34% (25/74) (chi2 test for trend of odds = 0.000). Non-Vaccine serotypes had an increasing trend and rose from 13% (5/40) to 27% (20/74) (chi2 test for trend of odds = 0.038). Reported total case fatality was 19% (87/466). The highest, at 36% (20/56), was reported in 2013. After adjusting for age, Streptococcus pneumoniae serotype 3 was associated with death from IPD (adjusted OR 2.3 95%CI 1.25-4.12 p 0.007). Surveillance data indicate evidence of serotype replacement with an increasing trend of serotype 19A and PPV23nonPCV13 and Non-Vaccine serotypes. Serotype 3 and age were associated with fatal IPD outcome. Further studies of S. pneumoniae carriage would be useful in providing more evidence to characterize serotypes' circulation.

The direct effect of pneumococcal conjugate vaccines on invasive pneumococcal disease in children in the Latin American and Caribbean region (SIREVA 2006-17): a multicentre, retrospective observational study

BACKGROUND

Streptococcus pneumoniae isolated from patients with invasive pneumococcal disease has been subjected to laboratory-based surveillance in Latin American and Caribbean countries since 1993. Invasive pneumococcal diseases remain a major cause of death and disability worldwide, particularly in children. We therefore aimed to assess the direct effect of pneumococcal conjugate vaccines (PCVs) on the distribution of pneumococcal serotypes causing invasive pneumococcal disease in children younger than 5 years before and after PCV introduction.

METHODS

We did a multicentre, retrospective observational study in eight countries that had introduced PCV (ie, PCV countries) in the Latin American and Caribbean region: Argentina, Brazil, Chile, Colombia, Dominican Republic, Mexico, Paraguay, and Uruguay. Cuba and Venezuela were also included as non-PCV countries. Isolate data for Streptococcus pneumoniae were obtained between 2006 and 2017 from children younger than 5 years with an invasive pneumococcal disease from local laboratories or hospitals. Species' confirmation and capsular serotyping were done by the respective national reference laboratories. Databases from the Sistema Regional de Vacunas (SIREVA) participating countries were managed and cleaned in a unified database using Microsoft Excel 2016 and the program R (version 3.6.1). Analysis involved percentage change in vaccine serotypes between pre-PCV and post-PCV periods and the annual reporting rate of invasive pneumococcal diseases per 100 000 children younger than 5 years, which was used as a population reference to calculate percentage vaccine type reduction.

FINDINGS

Between 2006 and 2017, 12 269 isolates of invasive pneumococcal disease were collected from children younger than 5 years in the ten Latin American and Caribbean countries. The ten serotypes included in ten-valent pneumococcal conjugate vaccine (PCV10) decreased significantly (p<0·0001) after any PCV introduction, except for the Dominican Republic. The percentage change for the ten vaccine serotypes in PCV10 countries was -91·6% in Brazil (530 [72·9%] of 727 before, 27 [6·1%] of 441 after); -85·0% in Chile (613 [72·6%] of 844 before, 44 [10·9%] of 404] after); -84·7% in Colombia (231 [63·1%] of 366 before, 34 [9·7%] of 352 after); and -73·8% in Paraguay (127 [77·0%] of 165 before, 22 [20·2%] of 109 after). In the 13-valent pneumococcal conjugate vaccine (PCV13) countries, the percentage change for the 13 vaccine serotypes was -59·6% in Argentina (853 [85·0%] of 1003 before, 149 [34·3%] of 434 after); -16·5% in the Dominican Republic (95 [80·5%] of 118 before, 39 [67·2%] of 58 after); -43·7% in Mexico (202 [73·2%] of 276 before, 63 [41·2%] of 153 after); and -45·9% in Uruguay (138 [80·7%] of 171 before, 38 [43·7%] of 87 after). Annual reporting rates showed a reduction from -82·5% (6·21 before vs 1·09 after per 100 000, 95% CI -61·6 to -92·0) to -94·7% (1·15 vs 0·06 per 100 000, -89·7 to -97·3) for PCV10 countries, and -58·8% (2·98 vs 1·23 per 100 000, -21·4 to -78·4) to -82·9% (7·80 vs 1·33 per 100 000, -76·9 to -87·4) for PCV13 countries. An increase in the amount of non-vaccine types was observed in the eight countries after PCV introduction together with an increase in their percentage in relation to total invasive strains in the post-PCV period.

INTERPRETATION

SIREVA laboratory surveillance was able to confirm the effect of PCV vaccine on serotypes causing invasive pneumococcal disease in the eight PCV countries. Improved monitoring of the effect and trends in vaccine type as well as in non-vaccine type isolates is needed, as this information will be relevant for future decisions associated with new PCVs.

FUNDING

None.

TRANSLATIONS

For the Portuguese and Spanish translations of the abstract see Supplementary Materials section.

Pneumococcal susceptibility to antibiotics in carriage: a 17 year time series analysis of the adaptive evolution of non-vaccine emerging serotypes to a new selective pressure environment

BACKGROUND

Pneumococcal conjugate vaccine (PCV) implementations led to major changes in serotype distribution and antibiotic resistance in carriage, accompanied by changes in antibiotic consumption.

OBJECTIVES

To assess the dynamic patterns of antimicrobial non-susceptibility across non-PCV13 serotypes following PCV implementations.

METHODS

We conducted a quasi-experimental interrupted time series analysis based on a 17 year French nationwide prospective cohort. From 2001 to 2018, 121 paediatricians obtained nasopharyngeal swabs from children with acute otitis media who were aged 6 months to 2 years. The main outcome was the rate of penicillin-non-susceptible pneumococci (PNSP), analysed by segmented regression.

RESULTS

We enrolled 10 204 children. After PCV13 implementation, the PNSP rate decreased (-0.5% per month; 95% CI -0.9 to -0.1), then, after 2014, the rate slightly increased (+0.7% per month; 95% CI +0.2 to +1.2). Global antibiotic use within the previous 3 months decreased over the study period (-22.2%; 95% CI -33.0 to -11.3), but aminopenicillin use remained high. Among the main non-PCV13 serotypes, four dynamic patterns of penicillin susceptibility evolution were observed, including unexpected patterns of serotypes emerging while remaining or even becoming penicillin susceptible. In contrast to PNSP strains, for these latter patterns, the rate of co-colonization with Haemophilus influenzae increased concomitant with their emergence.

CONCLUSIONS

In a context of continuing high antibiotic selective pressure, a progressive increase in PNSP rate was observed after 2014. However, we highlighted an unexpected variability in dynamic patterns of penicillin susceptibility among emerging non-PCV13 serotypes. Antibiotic resistance may not be the only adaptive mechanism to antimicrobial selective pressure, and co-colonization with H. influenzae may be involved.

A Phase II Trial of Safety, Tolerability and Immunogenicity of V114, a 15-Valent Pneumococcal Conjugate Vaccine, Compared With 13-Valent Pneumococcal Conjugate Vaccine in Healthy Infants

BACKGROUND

Pneumococcal disease remains a public health priority worldwide. This phase 2 study (V114-008; NCT02987972; EudraCT 2016-001117-25) compared safety and immunogenicity of 2 clinical lots of V114 (investigational 15-valent pneumococcal vaccine: 1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19F, 19A, 22F*, 23F, 33F*) to 13-valent pneumococcal conjugate vaccine (PCV13) in healthy infants (*serotypes unique to V114).

METHODS

Healthy infants 6-12 weeks old were randomized to receive a 4-dose regimen of V114 Lot 1, V114 Lot 2 or PCV13 at 2, 4, 6 and 12-15 months old. Adverse events were evaluated after each dose. Primary immunogenicity endpoint was to demonstrate noninferiority of V114 Lot 1 and V114 Lot 2 relative to PCV13 based on proportion of infants achieving serotype-specific IgG concentration ≥0.35 µg/mL for 13 serotypes shared with PCV13 at 1 month postdose 3 (PD3). Serotype-specific IgG geometric mean concentrations (GMCs) for all 15 V114 serotypes were measured at PD3, predose 4 and 1 month postdose 4 (PD4).

RESULTS

Overall, 1044 of 1051 randomized infants received ≥1 dose of vaccine (V114 Lot 1 [n = 350], V114 Lot 2 [n = 347] or PCV13 [n = 347]). Adverse events were generally comparable across groups. At PD3, both V114 lots met noninferiority criteria for all 13 serotypes shared with PCV13. IgG GMCs were comparable among V114 and PCV13 recipients at PD3 and PD4. Serotype 3 responses were higher following receipt of V114 than PCV13. Both V114 lots induced higher GMCs than PCV13 to the 2 unique V114 serotypes.

CONCLUSIONS

Immunogenicity of both V114 lots was noninferior to PCV13 for all 13 shared serotypes between the 2 vaccines and displayed comparable safety and tolerability profiles to PCV13.