Early impact of sequential introduction of 7-valent and 13-valent pneumococcal conjugate vaccine on IPD in Israeli children <5 years: an active prospective nationwide surveillance

Immunogenicity and safety of a multi-human dose formulation of Biological E's 14-valent pneumococcal polysaccharide conjugate vaccine (PNEUBEVAX 14®) administered to 6-8-week-old healthy infants: a phase 3, single-blind, randomized, active-controlled study

Background

Pneumococcal conjugate vaccines (PCVs) have considerably reduced the burden of invasive pneumococcal disease (PD) worldwide. Consequently, though, there has been an increase in non-vaccine serotype-induced PD particularly at both the extremes of age. Biological E has developed a 14-valent PCV (PNEUBEVAX 14®) that includes additional serotypes 22F and 33F. PNEUBEVAX 14® was shown to be safe, immunogenic, and non-inferior to Prevenar-13® (PCV-13) when administered to infants in a pivotal phase 3 trial. In this study, the multi-dose presentation of PNEUBEVAX 14® with 2-phenoxyethanol as a preservative was assessed for safety and immunogenicity in infants.

Methods

This was a phase 3, single-blind, randomized, active-controlled study in 6-8-week-old healthy infants, conducted at three sites across India. The safety and immunogenicity of multi-dose presentation of PNEUBEVAX 14® were assessed in a 6-10-14-week dosing schedule, with 300 infants randomized to receive either PNEUBEVAX 14® or PCV-13. Safety-wise solicited local reactions and systemic events, unsolicited adverse events (AEs), serious AEs, and medically attended AEs (MAAEs) were recorded and analyzed. Immunogenicity was assessed by measuring anti-pneumococcal capsular polysaccharide (anti-PnCPS) immunoglobulin G (IgG) antibodies for all 14 serotypes, as well as cross-reactivity to serotype 6A.

Findings

The safety aspects of the multi-dose presentation of PNEUBEVAX 14® and PCV-13 were comparable with 23.3% of subjects having AEs in each of the two arms. There were no serious AEs, medically attended AEs, or deaths in either of the two study arms. Reported AEs were mild and solicited in nature, with injection site swelling and injection site pain being the most common AEs in both arms. The multi-dose presentation of PNEUBEVAX 14® was found to induce a robust immune response, including the new serotypes 22F and 33F. Importantly, PNEUBEVAX 14® also induced cross-reactive antibodies against serotype 6A.

Interpretation

The multi-dose presentation of PNEUBEVAX 14® is both safe and immunogenic when administered to 6-8-week-old infants in a 6-10-14-week dosing schedule. These results extend the findings of a pivotal phase 3 study of the single-dose presentation of PNEUBEVAX 14® that showed that it was safe, robustly immunogenic, and non-inferior to PCV-13 in the same age group and dosing schedule. Taken together, these data suggest that both the single-dose and multi-dose presentations of PNEUBEVAX 14® can be safely administered to infants to prevent pneumococcal disease caused by Streptococcus pneumoniae.

Clinical Trial Registration

https://ctri.nic.in/Clinicaltrials/pmaindet2.php?EncHid=NTk0MzA=&Enc=&userName=, identifier CTRI/2021/10/037067.

Global impact of ten-valent and 13-valent pneumococcal conjugate vaccines on invasive pneumococcal disease in all ages (the PSERENADE project): a global surveillance analysis

BACKGROUND

Pneumococcal conjugate vaccines (PCVs) that are ten-valent (PCV10) and 13-valent (PCV13) became available in 2010. We evaluated their global impact on invasive pneumococcal disease (IPD) incidence in all ages.

METHODS

Serotype-specific IPD cases and population denominators were obtained directly from surveillance sites using PCV10 or PCV13 in their national immunisation programmes and with a primary series uptake of at least 50%. Annual incidence rate ratios (IRRs) were estimated comparing the incidence before any PCV with each year post-PCV10 or post-PCV13 introduction using Bayesian multi-level, mixed-effects Poisson regressions, by site and age group. All site-weighted average IRRs were estimated using linear mixed-effects regression, stratified by product and previous seven-valent PCV (PCV7) effect (none, moderate, or substantial).

FINDINGS

Analyses included 32 PCV13 sites (488 758 cases) and 15 PCV10 sites (46 386 cases) in 30 countries, primarily high income (39 sites), using booster dose schedules (41 sites). By 6 years after PCV10 or PCV13 introduction, IPD due to PCV10-type serotypes and PCV10-related serotype 6A declined substantially for both products (age <5 years: 83-99% decline; ≥65 years: 54-96% decline). PCV7-related serotype 19A increases before PCV10 or PCV13 introduction were reversed at PCV13 sites (age <5 years: 61-79% decline relative to before any PCV; age ≥65 years: 7-26% decline) but increased at PCV10 sites (age <5 years: 1·6-2·3-fold; age ≥65 years: 3·6-4·9-fold). Serotype 3 IRRs had no consistent trends for either product or age group. Non-PCV13-type IPD increased similarly for both products (age <5 years: 2·3-3·3-fold; age ≥65 years: 1·7-2·3-fold). Despite different serotype 19A trends, all-serotype IPD declined similarly between products among children younger than 5 years (58-74%); among adults aged 65 years or older, declines were greater at PCV13 (25-29%) than PCV10 (4-14%) sites, but other differences between sites precluded attribution to product.

INTERPRETATION

Long-term use of PCV10 or PCV13 reduced IPD substantially in young children and more moderately in older ages. Non-vaccine-type serotypes increased approximately two-fold to three-fold by 6 years after introduction of PCV10 or PCV13. Continuing serotype 19A increases at PCV10 sites and declines at PCV13 sites suggest that PCV13 use would further reduce IPD at PCV10 sites.

FUNDING

Bill & Melinda Gates Foundation as part of the WHO Pneumococcal Vaccines Technical Coordination Project.

Orbital complications of pediatric acute rhinosinusitis in the pneumococcal conjugate vaccine era

OBJECTIVES

To evaluate the impact of the pneumococcal conjugate vaccines (PCVs) introduction on the orbital complications of acute rhino-sinusitis (OC-ARS).

METHODS

A retrospective cohort study of all pediatric patients with OC-ARS during the period 2002-2019. Data included clinical, demographic, laboratory, and microbiology findings. Patients were divided into three groups: before PCV7 introduction (group 1), after PCV7 and before PCV13 (group 2), and after PCV13 (group 3).

RESULTS

Of 265 enrolled patients, 117, 39, and 109 were assigned to groups 1, 2, and 3. During the study period, a significant decrease was recorded in the percentages of patients in Chandler classification severity category 1, with an increase in patients in category 3 (P = 0.011). The yearly incidence of OC-ARS decreased from 12.64 cases per 100,000 population in 2002 to 5.56 per 100,000 in 2008, and 2.99 per 100,000 in 2019 (P < 0.001). Patients aged 0-4 years showed a dramatic decrease from 29 cases per 100,000 population in 2002 to 4.27 per 100,000 in 2019 (P < 0.001). The pathogens retrieved from all cultures performed were Streptococcus pneumoniae (32.5%), non-typeable Haemophilus influenzae (27.5%), Streptococcus Species, (12.5%), and Staphylococcus aureus (20%), with no changes in distribution during the study periods. Surgery was performed in 28 (10.6%) patients.

CONCLUSIONS

A significant decrease was seen in the overall incidence of OC-ARS, mainly attributable to the decrease in patients aged 0-4 years. An increase was recorded in the severity of the disease following PCVs introduction.

Study of pediatric invasive pneumococcal disease in the 13-pneumococcal conjugated vaccine era

BACKGROUND

Invasive pneumococcal disease (IPD) remains a significant concern among children under 5, despite vaccination efforts. This study assessed IPD prevalence and associated risks in pediatric population.

METHODS

An observational, retrospective, multicenter study in Comunidad Valenciana, Spain, of IPD cases in children under 13 from January 2012 to September 2022. Data from the CV Microbiology Surveillance Network (RedMIVA) and medical records were reviewed.

RESULTS

A total of 379 IPD cases in 377 patients were analyzed, predominantly males (54.11 %) under 5 (81.17 %). PCV13 vaccination notably reduced PCV13-serotypes IPD (p=0.0002), except serotype 3. Pneumonia was common, with half having underlying conditions (50.40 %). Worse outcomes occurred in patients with neurological disorders (ANOVA, p=0.57). Vaccine failures often involved underlying conditions (63 %) and serotypes 3 and 19A. Immunodeficiencies may relate to recurrent IPD, but evidence is limited.

CONCLUSION

Despite vaccination, IPD still impacts children, influenced by immunological status, affecting severity and mortality.

Treatment of mild to moderate community-acquired pneumonia in previously healthy children: an Italian intersociety consensus (SIPPS-SIP-SITIP-FIMP-SIAIP-SIMRI-FIMMG-SIMG)

Community-acquired pneumonia (CAP) is an acute infection of the lung parenchyma acquired outside the hospital or other healthcare settings, typically affecting previously healthy individuals. This intersociety consensus aims to provide evidence-based recommendations for the antibiotic treatment of mild to moderate CAP in previously healthy children in Italy.A systematic review was conducted to identify the most recent and relevant evidence. Embase, Scopus, PubMed, and Cochrane databases were systematically screened, with a date restriction from 2012 to April 2024, but without language limitations. The review included studies conducted in high-income countries on antibiotic therapy in children over 3 months of age diagnosed with mild-moderate CAP. The certainty of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methods. The final recommendations were obtained through a Delphi consensus of an expert panel.Amoxicillin is the first-line treatment if the child is at least immunized against Haemophilus influenzae type b (low/very low quality of evidence, strong recommendations), while amoxicillin-clavulanate or second- or third-generation cephalosporins should be prescribed for those unimmunized or with incomplete immunization coverage for both H. influenzae type b and Streptococcus pneumoniae (low/very low quality of evidence, strong recommendations). Macrolides should be considered in addition to amoxicillin in children over 5 years old, if symptoms persist and the clinical condition remains good after 48 h of therapy (low/very low quality of evidence, strong recommendations). The dosage of amoxicillin is 90 mg/kg/day divided in three doses, although two doses could be considered to improve compliance (moderate quality of evidence, weak recommendations). A five-day duration of therapy is recommended, with clinical monitoring and re-assessment approximately 72 h after the start of antibiotic treatment to evaluate symptom resolution (moderate quality of evidence, strong recommendations).To improve the management of CAP in pediatric patients, we have developed this consensus based on a thorough review of the best available evidence and extensive discussions with an expert panel. However, further efforts are needed. Future research should focus on enhancing diagnostic accuracy, optimizing antibiotic utilization, comparing the efficacy of different antibiotic regimens, and determining the optimal dosage and duration of treatment in different setting.

PCV15, a pneumococcal conjugate vaccine, for the prevention of invasive pneumococcal disease in infants and children

INTRODUCTION

Streptococcus pneumoniae is a causative agent of pneumonia and acute otitis media (AOM), as well as invasive diseases such as meningitis and bacteremia. PCV15 (V114) is a new 15-valent pneumococcal conjugate vaccine (PCV) approved for use in individuals ≥6 weeks of age for the prevention of pneumonia, AOM, and invasive pneumococcal disease.

AREAS COVERED

This review summarizes the V114 Phase 3 development program leading to approval in infants and children, including pivotal studies, interchangeability and catch-up vaccination studies, and studies in at-risk populations. An integrated safety summary is presented in addition to immunogenicity and concomitant use of V114 with other routine pediatric vaccines.

EXPERT OPINION

Across the development program, V114 demonstrated a safety profile that is comparable to PCV13 in infants and children. Immunogenicity of V114 is comparable to PCV13 for all shared serotypes except serotype 3, where V114 demonstrated superior immunogenicity. Higher immune responses were demonstrated for V114 serotypes 22F and 33F. Results of the ongoing study to evaluate V114 efficacy against vaccine-type pneumococcal AOM and anticipated real-world evidence studies will support assessment of vaccine effectiveness and impact, with an additional question of whether higher serotype 3 immunogenicity translates to better protection against serotype 3 pneumococcal disease.

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.

Dynamics of invasive pneumococcal disease in infants < 2 years old following PCV7/13 implementation using two infant and a booster dose schedule: evidence for indirect protection of young infants, Israel, 2004 to 2019

BackgroundPneumococcal conjugated vaccine (PCV)7 and PCV13 programmes started in Israel from July 2009 and November 2010 respectively, with a 2+1 schedule (one dose at 2 months old, one at 4 months old, and a booster dose at 12 months old). Thereafter, invasive pneumococcal disease (IPD) rates substantially declined in children. Uptake of all three doses in < 2-year-olds since 2012 is > 90%. For still incompletely vaccinated infants (≤ 12 months old), how well the PCV 2+1 programme shields from IPD is not fully resolved.AimTo assess the adequacy of protection conferred by the 2+1 schedule PCV vaccination programme, particularly among incompletely-vaccinated infants.MethodsThis was a population-based, prospective, nationwide active IPD surveillance study in Israel, 2004-2019, in children < 24 months old. We estimated annual incidence rates (IR) of overall IPD, IPD caused by PCV13 serotypes (VT13), and non-PCV13 serotypes (NVT13). Annual IPD IRs were stratified by age: < 4 months (receiving ≤ 1 dose), 4-6 months (immediately post dose 2), 7-12 months (a few months post dose 2), and 13-23 months (post dose 3). Late-PCV (2004-2008) to pre-PCV13 (2016-2019) mean annual IR ratios (IRRs) were calculated.Results2,569 IPD episodes were recorded. VT13 decreased > 90% in all age groups, while NVT13 seemed to increase. All-IPD rates declined in all age groups by 56-70%. The 2+1 schedule impact on 7-12-month-old infants (pre-booster) was similar to that on 13-23-month-old children (post booster), with PCV13 IPD reductions of 97% and 98%, respectively.ConclusionsIndirect (herd) protection of infants, including < 4 month-olds with ≤ 1 PCV dose, was achieved by the 2+1 PCV schedule programme which thus seems adequate.

A Phase III, multicenter, randomized, double-blind, active comparator-controlled study to evaluate the safety, tolerability, and immunogenicity of V114 compared with PCV13 in healthy infants (PNEU-PED-EU-1)

BACKGROUND

V114 (15-valent pneumococcal conjugate vaccine [PCV]) contains all serotypes in 13-valent PCV (PCV13) and additional serotypes 22F and 33F. This study evaluated safety and immunogenicity of V114 compared with PCV13 in healthy infants, and concomitant administration with DTPa-HBV-IPV/Hib and rotavirus RV1 vaccines.

METHODS

V114 and PCV13 were administered in a 2+1 schedule at 2, 4, and 11-15 months of age. Adverse events (AEs) were collected on Days 1-14 following each vaccination. Serotype-specific anti-pneumococcal immunoglobulin G (IgG) was measured 30 days post-primary series (PPS), immediately prior to a toddler dose, and 30 days post-toddler dose (PTD). Primary objectives included non-inferiority of V114 to PCV13 for 13 shared serotypes and superiority of V114 to PCV13 for the two additional serotypes.

RESULTS

1184 healthy infants 42-90 days of age were randomized 1:1 to V114 (n = 591) or PCV13 (n = 593). Proportions of participants with solicited AEs and serious AEs were comparable between vaccination groups. V114 met pre-specified non-inferiority criteria for all 13 shared serotypes, based on the difference in proportions of participants with serotype-specific IgG concentrations ≥0.35 μg/mL (response rate; lower bound of two-sided 95% confidence interval [CI] >-10.0) and IgG geometric mean concentration (GMC) ratios (lower bound of two-sided 95% CI >0.5), and pre-specified superiority criteria for serotypes 22F and 33F (lower bound of two-sided 95% CI >10.0 for response rates and >2.0 for GMC ratios). Antibody responses to DTPa-HBV-IPV/Hib and RV1 vaccines met pre-specified non-inferiority criteria, based on antigen-specific response rates to DTPa-HBV-IPV/Hib and anti-rotavirus IgA geometric mean titers.

CONCLUSIONS

After a 2+1 schedule, V114 elicited non-inferior immune responses to 13 shared serotypes and superior responses to the two additional serotypes compared with PCV13, with comparable safety profile. These results support the routine use of V114 in infants.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT04031846; EudraCT: 2018-003787-31.

A phase 3, multicenter, randomized, double-blind, active-comparator-controlled study to evaluate the safety, tolerability, and immunogenicity of a 4-dose regimen of V114, a 15-valent pneumococcal conjugate vaccine, in healthy infants (PNEU-PED)

BACKGROUND

Pneumococcal disease (PD) remains a major health concern with considerable morbidity and mortality in children. Currently licensed pneumococcal conjugate vaccines (PCVs) confer protection against PD caused by most vaccine serotypes, but non-vaccine serotypes contribute to residual disease. V114 is a 15-valent PCV containing all 13 serotypes in Prevnar 13™ (PCV13) and additional serotypes 22F and 33F. This pivotal phase 3 study compared safety and immunogenicity of V114 and PCV13.

METHODS

1720 healthy infants were randomized 1:1 to receive a 4-dose regimen of V114 or PCV13 concomitantly with other routine pediatric vaccines. Safety was evaluated after each dose as proportion of participants with adverse events (AEs). Serotype-specific anti-pneumococcal immunoglobulin G (IgG) was measured at 1-month post-dose 3 (PD3), pre-dose 4, and 1-month post-dose 4 (PD4). IgG response rates, geometric mean concentrations (GMCs), and opsonophagocytic activity (OPA) were compared between vaccination groups.

RESULTS

The proportion, maximum intensity, and duration of injection-site, systemic, and serious AEs were generally comparable between V114 and PCV13 groups. In comparison to PCV13, V114 met non-inferiority criteria for all 15 serotypes based on IgG response rates at PD3. V114 met non-inferiority criteria by IgG GMCs for all serotypes at PD3 and PD4, except for serotype 6A at PD3. V114-induced antibodies had bactericidal activity as assessed by OPA. Further, V114 met superiority criteria for shared serotype 3 and unique serotypes 22F and 33F compared to PCV13 by serotype-specific IgG GMCs at both PD3 and PD4. Immunogenicity of concomitantly administered routine pediatric vaccines was comparable in V114 and PCV13 groups.

CONCLUSIONS

In healthy infants, V114 displays acceptable safety and tolerability profiles and generates comparable immune responses to PCV13. V114 also met superiority criteria for serotypes 3, 22F, and 33F. These results support use of V114 for prevention of PD as part of routine infant vaccination schedules.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT03893448; EudraCT: 2018-004109-21.

Streptococcus pneumoniae as cause of acute otitis media (AOM) in Slovak children in the pneumococcal conjugate vaccine era (2008-2019)

AIM

Little data is available on pneumococcal serotypes and their antimicrobial resistance in the pneumococcal conjugate vaccination era in young children with acute otitis media (AOM). Here such data is provided from Slovakia, acountry with sequential introduction and parallel-use of the three commercially available pneumococcal conjugate vaccines (PCVs; PCV7; PCV13; PCV10).

METHODS

This observational study takes advantage of the fact that tympanocentesis is the standard of care in children with AOM in Slovakia. Over the 12 year observation period, participating pediatric ENT specialists sent samples taken during tympanocentesis from children with AOM to their local MEDIRIX laboratories for identification of bacteria. Pneumcoccal isolates were serotyped and tested for antimicrobial resistance. Incidence data could be calculated from 1 region.

RESULTS

Study participation and completeness of typing increased over time. Based on testing of 1,131 isolates over 12 years, PCV7-serotypes rapidly waned after PCV7 introduction in 2009 and had virtually disappeared in 2014. The maximum fraction of PCV10-only isolates (1, 5, 7F) was 2.7 % (2009) whereas the additional 3 PCV-serotypes (3, 6A, 19A) in PCV13 represented the largest proportion of pneumococcal AOM cases as of 2010. This finding remained unchanged during the period of highest PCV10-market share (2012-2017) and even until the end of the observation period (2019). The fraction of untypeable pneumococci (<6 %) and non-PCV13-serotypes (16-34 %) increased 2012-2017, but decreased again thereafter. Serotype 19A evolved as the most relevant (multidrug-) resistant pneumococcal serotype, again particularly during the time with high sales of PCV10 (2012-2017). Incidence data from the Bratislava region document a huge impact of PCV use (77 % vaccine uptake: mainly PCV13) on AOM in children < 6 years. Serotypes 19A and 3 remain the only relevant pneumococcal serotypes in young Slovakian children with AOM.

CONCLUSIONS

As AOM is one of the most common bacterial infections in children < 6 years, the observed benefits of PCVs in reducing vaccine serotypes have been tremendous. With sequential / parallel-use of PCVs, serotypes 3 and (MDR-) 19A today make the largest proportion (about 2/3) of pneumococcal AOM in Slovakia. This data will help to further guide the choice of pneumococcal conjugate vaccines for pediatricians and parents.

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.

The impact of the pneumococcal conjugate vaccines on the incidence of community-acquired alveolar pneumonia in premature compared with in term-born infants

BACKGROUND

Preterm-born children are prone to respiratory infections and complications during infancy and early childhood. In Israel, pneumococcal conjugated vaccines (PCVs) were introduced in 2009-2010, with high vaccination coverage. We assessed the impact of PCV implementation on community-acquired alveolar pneumonia (CAAP) in children < 2 years old born prematurely, in comparison with term born infants.

METHODS

We conducted a prospective, active, population-based surveillance of children < 2 years old with radiologically-proven CAAP, visiting the only regional medical center. CAAP incidence in the pre-PCV and post-PCV eras were compared in early premature (29-32 weeks gestational age [WGA]), late premature (33-36 WGA) and term-born infants (>36 WGA).

RESULTS

Of 214,947 births during the study period, 6'791 CAAP episodes were diagnosed; 211, 653 and 5,806 were in early premature, late premature and term infants, respectively. After PCV implementation, overall CAAP visits were reduced by 44% (95% CI 36-51): 60%, 21% and 45% among those born early preterm, late preterm and at term, respectively (statistically significant for children born early preterm and at term). For outpatients, the respective rate reductions were 79%, 40% and 65% (statistically significant for the children born at term). Importantly, the mean annual rates in the post-PCV period became similar in all 3 groups. The rate reductions among the hospitalized children were lower those that among the non-hospitalized children, with reductions of 56%, 16% and 33% for the three groups, respectively (statistically significant for early preterm and at term children).

CONCLUSIONS

CAAP reduction trends after PCV implementation for preterm-born infants were similar to those for term-born infants. Whether this was because of similar direct PCV- protection, because of indirect (herd) protection or both, is unclear. Post-PCV implementation, the gaps in CAAP rates between infants born prematurely and at term were reduced.

The impact of pneumococcal conjugate vaccine on the prevalence and severity of hospitalizations for pneumonia in children

Pneumococcal conjugate vaccines (PCV) were introduced into the Israeli national immunization plan starting with the heptavalent PCV7 in 2009 and then PCV13 in the late 2010. The objective of this study was to determine the vaccines' impact on hospitalization rates for community-acquired pneumonia on the severity of the pneumonia episodes and upon pneumococcal serotype distribution. We retrospectively reviewed all children hospitalized in our institution with pneumonia, aged between 1 and 16 years, between the years 2006 and 2015. Demographic, clinical, and laboratory data between three time periods: pre-PCV, PCV7, and PCV13, were compared. During the study period, 1375 children were hospitalized with pneumonia. A gradual decline in hospitalization rates due to pneumonia was observed starting in 2006 in the pre-PCV period and continued until after the introduction of PCV13. A similar trend was observed in pneumonias with a culture positive for S. pneumoniae. Pleural effusion was observed in 24% of all pneumonias, and this percentage was stable throughout the study period. The average age at hospitalization increased during the study period, as did the average duration of hospital stay. Pneumococcal serotypes included in the vaccine were isolated less frequently during the study and non-vaccine serotypes tended to appear more frequently. Pediatric pneumonia hospitalization rates continued to decline since the introduction of PCV without increasing the frequency of complications. Pneumococcal serotype distribution shifted in parallel. Our findings confirm the efficacy of PCV and support the evidence to include more serotypes in the next generation of PCV.

Sentinel surveillance for bacterial pneumonia and meningitis in children under the age of 5 in a tertiary pediatric hospital in Colombia - 2016

Introduction:

Bacterial pneumonia and meningitis are vaccine-preventable diseases. Sentinel surveillance provides relevant information about their behavior.

Objective:

To present the data from sentinel surveillance carried out at the Fundación HOMI, Fundación Hospital Pediátrico La Misericordia in 2016.

Materials and methods:

We conducted a descriptive study from January 1 to December 31, 2016, on the daily surveillance of patients under 5 years of age diagnosed with pneumonia or bacterial meningitis according to PAHO's definitions. We identified the microorganisms using the automated VITEK^TM 2 system. Bacterial isolates were sent to the Microbiology Group at the Colombian Instituto Nacional de Salud for confirmation, serotyping, phenotypic, and genotypic characterization. Antimicrobial susceptibility profiles were established.

Results:

From 1,343 suspected cases of bacterial pneumonia, 654 (48.7%) were probable, 84% had complete Hib vaccination schedules, and 87% had complete pneumococcal vaccination schedules for age. Blood culture was taken in 619 (94.6%) and 41 (6.6%) were positive while S. pneumoniae was isolated in 17 (41%) of them. The most frequent serotype was 19A in five cases (29.4%), and four 19A serotypes were associated with the reference isolate ST320. The incidence rate of probable bacterial pneumonia was 7.3 cases/100 hospitalized patients, and lethality was 2.1%. As for bacterial meningitis, 22 suspected cases were reported, 12 (54%) were probable, four (33%) were confirmed: two by Escherichia coli and two by group C N. meningitidis. The incidence of probable bacterial meningitis was 0.14 cases/100 hospitalized patients.

Conclusion:

Streptococcus pneumoniae serotypes 19A and 3 were the most frequent cause of pneumonia. Spn19A is related to the multi-resistant clone ST320. Strengthening and continuing this strategy will allow understanding the impact of vaccination.

The 13-valent pneumococcal conjugate vaccine (PCV13) does not appear to provide much protection on combined invasive disease due to the six PCV13 non-PCV7 serotypes 1, 3, 5, 6A, 7F, and 19A in Kuwait during 2010-2019

Kuwait started immunizing children <2 y age with the 7-valent pneumococcal conjugate vaccine, PCV7 from August 2007. PCV7 was replaced by the 13-valent conjugate vaccine, PCV13 from August 2010. In a previous analysis of the results for the period, August 2010-July 2013 (period II), there was no evidence of serotype-specific protection for invasive disease against the additional six serotypes to PCV7 present in PCV13 (non-PCV7 serotypes) as evidenced by isolation from blood and cerebrospinal fluid in any of the age groups, <2 y, 2-5 y, 6-50 y, 51-65 y, and >65 y and all ages, compared to the pre-vaccination period, August 2003-July 2006 (period I). In the current study, we allowed additional time, August 2013-July 2019 (period III) for better vaccine effect and repeated the analysis. We did not find any significant decrease of invasive disease due to the non-PCV7 serotypes of PCV13 in period III and combined II and III periods compared to period I. However, these comparisons showed significant reductions for four of the six and total serotypes of PCV7, and total serotypes of PCV13. Reduction for total PCV13 serotypes was contributed by serotypes of PCV7. It appears that the six non-PCV7 serotypes in PCV13 do not offer much protection. Some contributory factors for the poor effect of the non-PCV7 serotypes may be related to few cases with underpowered statistical analysis, lack of vaccine coverage data, method of vaccine efficacy analysis based on vaccine serotypes relative to all serotypes and unusual rise in non-typeable isolates post vaccination that would have masked true serotypes.

Invasive pneumococcal disease in persons with predisposing factors is dominated by non-vaccine serotypes in Southwest Sweden

BACKGROUND

The pneumococcal conjugate vaccine PCV7 was introduced in Southwest Sweden in the child vaccination program in 2009, followed by PCV13 in 2010 and PCV10 in 2015. In this retrospective cohort study we assessed the pneumococcal serotype distribution in relation to predisposing factors, clinical manifestations and outcome during seven years after PCV introduction.

METHODS

Clinical data from 1278 patients with 1304 episodes of invasive pneumococcal disease (IPD) between January 2009 and December 2015 in Region Västra Götaland, Sweden, were retrospectively collected from medical records. Pneumococcal isolates were serotyped by gel diffusion and/or Quellung reactions performed at the Public Health Agency in Sweden. Associations between serotypes and clinical characteristics were statistically evaluated by use of Fisher's exact test, Mann-Whitney U test and Logistic regression analysis, whereas IPD episodes caused by serotypes over time were analyzed by Mantel-Haenszel chi-square test.

RESULTS

With the exception of serotype 3, the prevalence of PCV13 serotypes decreased during the study period, from 76% (n = 157) of all IPD episodes in 2009 to 25% (n = 42) in 2015 (p < 0.001) while non-PCV13 serotypes increased, mainly among patients ≥65 years and in patients with predisposing factors, including cardiovascular disease, pulmonary disease and malignancy (p < 0.001 for all). Patients with predisposing factors, including those with malignancy, immune deficiency or renal disease, were more likely to have IPD caused by a serotype not included in PCV13 rather than a vaccine-included serotype. Serotype 3 was associated with intensive care unit admissions while serotype 1 and 7F caused IPD among healthier and younger patients. PCV13 serotypes were associated with invasive pneumonia, and non-PCV13 serotypes were associated with bacteremia with unknown focus and with manifestations other than pneumonia or meningitis.

CONCLUSIONS

Non-PCV13 serotypes caused the majority of IPD cases in Southwest Sweden, especially in patients ≥65 years and in patients with predisposing factors. Serotype 3, included in PCV13, was prevalent and often caused severe disease.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Post-13-Valent Pneumococcal Conjugate Vaccine Dynamics in Young Children of Serotypes Included in Candidate Extended-Spectrum Conjugate Vaccines

After worldwide implementation of 10-valent and 13-valent pneumococcal conjugate vaccines (PCV10/PCV13), a 20-valent PCV (PCV20) was developed. We assessed dynamics of non-PCV13 additional PCV20 serotypes (VT20–13), compared with all other non-VT20 serotypes, in children <2 years of age in late PCV13 (2015–2017) and early PCV (2009–2011) periods. Our prospective population-based multifaceted surveillance included isolates from carriage in healthy children, children requiring chest radiography for lower respiratory tract infections (LRTIs), and children with non-LRTI illness, as well as isolates from acute conjunctivitis, otitis media (OM), and invasive pneumococcal disease (IPD). After PCV13 implementation, VT20–13 increased disproportionally in OM, IPD, and carriage in LRTI. VT20–13/non-VT20 prevalence ratio range was 0.26–1.40. VT20–13 serotypes were more frequently antimicrobial-nonsusceptible than non-VT20 serotypes. The disproportionate increase of VT20–13 in respiratory infections and IPD points to their higher disease potential compared with all other non-VT20 as a group.

Failures of 13-Valent Conjugated Pneumococcal Vaccine in Age-Appropriately Vaccinated Children 2-59 Months of Age, Spain

Vaccination with the 13-valent conjugated pneumococcal disease (PCV13) has reduced invasive pneumococcal disease (IPD), but there have been reports of vaccine failures. We performed a prospective study in children aged 2–59 months who received diagnoses of IPD during January 2012–June 2016 in 3 pediatric hospitals in Catalonia, Spain, a region with a PCV13 vaccination coverage of 63%. We analyzed patients who had been age-appropriately vaccinated but who developed IPD caused by PCV13 serotypes. We detected 24 vaccine failure cases. The serotypes involved were 3 (16 cases); 19A (5 cases); and 1, 6B, and 14 (1 case each). Cases were associated with children without underlying conditions, with complicated pneumonia (OR 6.65, 95% CI 1.91–23.21), and with diagnosis by PCR (OR 5.18, 95% CI 1.84–14.59). Vaccination coverage should be increased to reduce the circulation of vaccine serotypes. Continuous surveillance of cases of IPD using both culture and PCR to characterize vaccine failures is necessary.

Global genomic pathogen surveillance to inform vaccine strategies: a decade-long expedition in pneumococcal genomics

Vaccines are powerful agents in infectious disease prevention but often designed to protect against some strains that are most likely to spread and cause diseases. Most vaccines do not succeed in eradicating the pathogen and thus allow the potential emergence of vaccine evading strains. As with most evolutionary processes, being able to capture all variations across the entire genome gives us the best chance of monitoring and understanding the processes of vaccine evasion. Genomics is being widely adopted as the optimum approach for pathogen surveillance with the potential for early and precise identification of high-risk strains. Given sufficient longitudinal data, genomics also has the potential to forecast the emergence of such strains enabling immediate or pre-emptive intervention. In this review, we consider the strengths and challenges for pathogen genomic surveillance using the experience of the Global Pneumococcal Sequencing (GPS) project as an early example. We highlight the multifaceted nature of genome data and recent advances in genome-based tools to extract useful information relevant to inform vaccine strategies and treatment options. We conclude with future perspectives for genomic pathogen surveillance.

Dose-specific Effectiveness of 7- and 13-Valent Pneumococcal Conjugate Vaccines Against Vaccine-serotype Streptococcus pneumoniae Colonization in Children

BACKGROUND

Reduced-dose pneumococcal conjugate vaccine (PCV) schedules are under consideration in countries where children are recommended to receive 3 doses. Whereas PCV-derived protection against vaccine-serotype colonization is responsible for herd effects of vaccination, dose-specific PCV effectiveness against colonization endpoints is not known. We aimed to assess the performance of differing PCV schedules against vaccine-serotype colonization in children.

METHODS

From 2009-2016, we monitored pneumococcal carriage in southern Israel, where children should receive PCV at ages 2 months, 4 months, and 12 months (2 primary [p] +1 booster [b] schedule). We analyzed nasopharyngeal swabs and vaccination histories from 5928 children aged 0-59 months without symptoms of diseases potentially attributable to pneumococci. Matching individuals on age, sex, ethnicity, visit timing, and recent antibiotic receipt, we measured schedule-specific 7-valent PCV (PCV7) and 13-valent PCV (PCV13) effectiveness against vaccine-serotype colonization in a modified case-control framework. We sampled from the distribution of all possible case-control match assignments for statistical analyses.

RESULTS

Receiving 2 primary-series PCV13 doses conferred 53% (95% confidence interval [CI], 32-67%) protection against PCV13-serotype colonization at ages ≤12 months; 1 primary-series dose was not protective. A 2p+1b PCV13 series conferred 40% (95% CI, 4-67%) and 62% (95% CI, 33-83%) protection against PCV13-serotype colonization at ages 13-24 months and 25-59 months, respectively. Estimates suggested greater PCV13-conferred protection against PCV7-targeted serotypes than the 6 PCV13-only serotypes. As compared to children receiving 2p+1b PCV13 dosing, those receiving 1p+1b and 2p+0b schedules experienced 2.05-fold (95% CI, 1.12-5.00) and 3.33-fold (95% CI, 2.28-4.93) greater odds, respectively, of vaccine-serotype pneumococcal colonization at ages 13-24 months.

CONCLUSIONS

Our results demonstrate real-world effectiveness of 2p+1b PCV dosing against vaccine-serotype colonization. Reduced-dose schedules may confer lower protection against vaccine-serotype carriage during and beyond the first year of life.

Use of Chest Radiography Examination as a Probe for Pneumococcal Conjugate Vaccine Impact on Lower Respiratory Tract Infections in Young Children

BACKGROUND

Community-acquired alveolar pneumonia (CAAP) is considered a bacterial disease, mainly pneumococcal. CAAP rates markedly declined following 7- and 13-valent pneumococcal conjugate vaccine (PCV) introductions worldwide. In contrast, non-CAAP lower respiratory tract infections (NA-LRIs) are generally not considered pneumococcal diseases. We assessed CAAP, NA-LRIs, and overall visits with chest radiograph (CXR) examination rates in the pediatric emergency room in southern Israel before and after PCV implementation.

METHODS

This was an ongoing, prospective observational study. Our hospital serves a captive population of approximately 75 000 children aged <5 years, enabling incidence calculation. PCV7 and PCV13 were implemented in Israel in July 2009 and November 2010, respectively. All CXRs were analyzed according to the World Health Organization Standardization of Interpretation. We calculated CAAP, NA-LRI, and CXR examinations annual incidences from 2004 to 2017 and incidence rate ratios comparing the PCV13 (2014-2017) with the pre-PCV (2004-2008) periods.

RESULTS

Overall, 72 746 CXR examinations were recorded: 14% CAAP and 86% NA-LRI. CAAP, NA-LRI, and CXR examination visit rates declined by 49%, 34%, and 37%, respectively. This pattern was seen in Jewish and Bedouin children (the 2 ethnically distinct populations), with steeper declines observed among Jewish children and children aged >12 months.

CONCLUSIONS

PCV7/PCV13 implementation resulted in a marked decline in CAAP and overall visits with CXR examination rates in young children. Overall, approximately 14 750 hospital visits with CXR were prevented annually per 100 000 population aged <5 years. These findings suggest that although NA-LRIs are usually not considered pneumococcal, many can be prevented by PCVs.Pneumococcal conjugate vaccine (PCV7/PCV13) implementation resulted in significant declines in community-acquired alveolar pneumonia (CAAP) and overall chest radiography examination rates in young children. Although non-CAAP lower respiratory tract infections are usually not considered pneumococcal, many can be prevented by PCVs.

The impact of pneumococcal conjugate vaccine-13 on the incidence of pediatric community-acquired bacteremia

The purpose of this study was to estimate the impact of pneumococcal conjugate vaccine-13 (PCV-13) introduction into the national immunization program in Israel on pneumococcal and non-pneumococcal pediatric community-acquired bacteremia (CAB). This is a retrospective cohort study, including children ≤ 18 years old with CAB, who were hospitalized in Rambam Health Care Campus, a tertiary medical center serving northern Israel, between the years 2004 and 2016. The proportional admission rate of pneumococcal bacteremia among all CAB events and the incidence of CAB and pneumococcal bacteremia per 1000 hospital admissions were compared between the pre- and post-pneumococcal vaccine eras. A total of 275 CAB events were identified. Common isolates were Streptococcus pneumoniae (SPn) (26.9%), Staphylococcus aureus (12.4%), Brucella spp. (11.6%), E. coli (10.9%), and Streptococcus pyogenes (5.8%). The pneumococcal bacteremia rate per 1000 hospital admissions decreased significantly from 1.59 to 0.6 (p < 0.001). The proportional pneumococcal bacteremia rate decreased from 55 (34.4%) to 19 (16.5%) (p 0.001). Penicillin resistance among pneumococcal isolates decreased dramatically from 50.9 to 5.3% (p < 0.001). The rate of bacteremia caused by other pathogens has not been changed significantly at the post-vaccination era (p 0.053). However, an increase in the incidence of S. pyogenes bacteremia from 1.9 to 11.3% (p < 0.001) was noticed. In addition, an outbreak of Brucella bacteremia occurred during the years 2015-2016. This study demonstrates the double positive effect of PVC-13 introduction: a sharp decrease in the proportional rate of pneumococcal bacteremia and in the resistance of SPn to penicillin. Also, there was a moderate decline in the incidence of CAB in exception to bacteremia caused by S. pyogenes. This trend was reversed due to a Brucella outbreak.

Effectiveness of the 7- and 13-Valent Pneumococcal Conjugate Vaccines Against Vaccine-Serotype Otitis Media

Background

Despite the demonstrated impact of pneumococcal vaccine (PCV) implementation on otitis media (OM), demonstration of real-life serotype-specific effectiveness of the 7-valent and 13-valent PCVs (PCV7 and PCV13) is lacking owing to the paucity of culture-positive cases. Furthermore, prelicensure PCV13 efficacy against OM was not studied.

Methods

The study was conducted from October 2009 to July 2013. Case patients were children aged 5–35 months with OM (mostly complex OM [recurrent/nonresponsive, spontaneously draining, chronic with effusion]) from whom middle-ear fluid culture was obtained; controls were contemporary children with rotavirus-negative gastroenteritis in a prospective population-based rotavirus surveillance, from the same age group with similar ethnic distribution and geographic location. Vaccine effectiveness (VE) was estimated as 1 minus the odds ratio using unconditional logistic regression, adjusting for time since PCV implementation, age, and ethnicity.

Results

A total of 223 case patients and 1370 controls were studied. Serotypes 19F and 19A together caused 56.1% of all vaccine-type (VT) OM. VE of ≥2 PCV doses in children aged 5–35 months was demonstrated as follows: PCV7 against OM due to PCV7 serotypes, 57.2% (95% confidence interval, 6.0%–80.5%); PCV13 against OM due to PCV13 serotypes, 77.4% (53.3%–92.1%); PCV13 against OM due to the 6 additional non-PCV7 serotypes 67.4% (17.6%–87.1%); PCV13 against OM due to serotype 19F, 91.3% (1.4%–99.2%); and PCV13 against OM due to serotype 3, 85.2% (23.9%–98.4%). PCV7 and PCV13 VE against OM due to serotype 19A in children aged 12–35 months was 72.4% (95% confidence interval, 6.2%–91.9%) and 94.6% (33.9%–99.6%), respectively.

Conclusions

PCV7 and PCV13 were effective against complex OM caused by the targeted serotypes.

Serotype distribution and antimicrobial Susceptibility of Streptococcus pneumoniae isolated from patients with pneumococcal pneumonia

Introduction: Streptococcus pneumoniae is a major cause of community-acquired pneumonia (CAP). In Serbia, pneumococcal conjugate vaccines PCV-10 and PCV-13 were licensed for immunization in 2018. Aim: The aim of this study was to evaluate serotype distribution and antimicrobial susceptibility of S. pneumoniae isolated from patients with pneumococcal pneumonia. Material and methods: Isolates of S. pneumoniae were recovered from patients with CAP addmitted to 18 hospitals throughout Serbia from 2012-2020. Confirmation of the identification was performed using lytA gene detection by PCR. Serotyping and antimicrobial susceptibility testing was performed by Quellung reaction and disk diffusion/gradient test, respectively. Interpretation of the susceptibility testing was done according to the current European Committee on Antimicrobial Susceptibility Testing recommendations. Results: During the study period, a total of 100 isolates of S. pneumoniae were collected. Overall, 19 pneumococcal serotypes were identified. The predominant types observed, in order of decreasing frequency, were 3 (37%), 14 (16%), 6B (6%), 7F (5%), 9V (4%), and 4 (4%); further, 2% of the isolates were non-typeable. However, the most common serotype among children < 2 years old was 14 (27.3%). The vaccine coverage of strains isolated from children < 5 years was higher with PCV-13 compared to PCV-10 (86,7% vs. 46,7%, p = 0.008). Additionally, the vaccine coverage of pneumococci isolated from patients >2 years was higher with the PPV-23 than with PCV-13 (96.6% vs. 84.3%, p = 0.0230). Ten isolates (10%) were PPV-23/nonPCV-13, whereas four isolates (4%) were non-typable (17A, 23A, and 9A). Serotype 3 significantly increased from pre-vaccine to post-vaccine period (30.8% vs. 60.8%, p = 0.0108). The overall antimicrobial resistance rates were as follows: penicillin - 9%, ceftriaxone - 2%, erythromycin - 24%, clindamycin - 16%, tetracycline - 11%, and trimethoprim-sulfamethoxazole - 21%. Conclusion: More than 70% of the isolated strains belonged to the serotypes 3, 14, 6B, 9B, and 4. The highest resistance rates of the tested pneumococci were found for macrolides and trimethoprim-sulfamethoxazole.

Effectiveness of pneumococcal conjugate vaccines against community-acquired alveolar pneumonia attributable to vaccine-serotype Streptococcus pneumoniae among children

INTRODUCTION

Streptococcus pneumoniae is a leading cause of pneumonia among children. However, owing to diagnostic limitations, the protection conferred by pneumococcal conjugate vaccines (PCVs) against pediatric pneumonia attributable to vaccine-serotype pneumococci remains unknown.

METHODS

We analyzed data on vaccination and nasopharyngeal pneumococcal detection among children <5 years old with community-acquired alveolar pneumonia (CAAP; "cases") and those without respiratory symptoms ("controls"), who were enrolled in population-based prospective surveillance studies in southern Israel between 2009-18. We measured PCV-conferred protection against carriage of vaccine-serotype pneumococci via the relative risk of detecting these serotypes among vaccinated versus unvaccinated controls. We measured protection against progression of vaccine serotypes from carriage to CAAP via the relative association of vaccine-serotype detection in the nasopharynx with CAAP case status, among vaccinated and unvaccinated children. We measured PCV-conferred protection against CAAP attributable to vaccine-serotype pneumococci via the joint reduction in risks of carriage and disease progression.

RESULTS

Our analyses included 1,032 CAAP cases and 7,743 controls. At ages 12-35 months, a PCV13 schedule containing two primary doses and one booster dose provided 87.2% (95% confidence interval: 8.1-100.0%) protection against CAAP attributable to PCV13-serotype pneumococci, and 92.3% (-0.9-100.0%) protection against CAAP attributable to PCV7-serotype pneumococci. Protection against PCV13-serotype and PCV7-serotype CAAP was 67.0% (-424.3-100.0%) and 67.7% (-1962.9-100.0%), respectively, at ages 36-59 months. At ages 4-11 months, two PCV13 doses provided 98.9% (-309.8-100.0%) and 91.4% (-191.4-100.0%) against PCV13-serotype and PCV7-serotype CAAP.

CONCLUSIONS

Among children, PCV-conferred protection against CAAP attributable to vaccine-targeted pneumococcal serotypes resembles protection against vaccine-serotype invasive pneumococcal disease.

A Nationwide Outbreak of Invasive Pneumococcal Disease in Israel Caused by Streptococcus Pneumoniae Serotype 2

BACKGROUND

Invasive pneumococcal disease (IPD) caused by Streptococcus pneumoniae serotype 2 (Sp2) is infrequent. Large scale outbreaks have not been reported following pneumococcal conjugate vaccine (PCV) implementation. We describe a Sp2 IPD outbreak in Israel, in the 13-valent PCV (PCV13) era, with focus on Sp2 population structure and evolutionary dynamics.

METHODS

The data derived from a population-based, nationwide active surveillance of IPD since 2009. 7-valent PCV (PCV7)/PCV13 vaccines were introduced in July 2009 and November 2010, respectively. Sp2 isolates were tested for antimicrobial susceptibility, Multilocus Sequence Typing (MLST) and Whole Genome Sequencing (WGS) analysis.

RESULTS

Overall, 170 Sp2 IPD cases were identified during 2009-2019; Sp2 increased in 2015 and caused 6% of IPD during 2015-2019, a 7-fold increase compared with 2009-2014.The outbreak was caused by a previously unreported molecular type (ST-13578), initially observed in Israel in 2014. This clone caused 88% of Sp2 during 2015-2019. ST-13578 is a single-locus variant of ST-1504, previously reported globally, including in Israel. WGS analysis confirmed clonality among the ST-13578 population. Single-nucleotide polymorphisms-dense regions support a hypothesis that the ST-13578 outbreak clone evolved from ST-1504 by recombination.All tested strains were penicillin-susceptible (MIC <0.06 μg/mL). The ST-13578 clone was identified almost exclusively (99%) in the Jewish population and was mainly distributed in 3/7 Israeli districts. The outbreak is still ongoing, although declining since 2017.Conclusions: To the best of our knowledge, this is the first widespread Sp2 outbreak since PCV13 introduction worldwide, caused by the emerging ST-13578 clone.

Divergent serotype replacement trends and increasing diversity in pneumococcal disease in high income settings reduce the benefit of expanding vaccine valency

Streptococcus pneumoniae is a significant cause of otitis media, pneumonia, and meningitis. Only seven of the approximately 100 serotypes were initially included in the pneumococcal polysaccharide conjugate vaccine (PCV) in 2000 before it was expanded in subsequent years. Although the invasive pneumococcal disease (IPD) incidence due to vaccine serotypes (VT) has declined, partial replacement by non-vaccine serotypes (NVT) was observed following widespread vaccine uptake. We conducted a trend analysis assembling the available evidence for PCV impact on European, North American and Australian national IPD. Significant effectiveness against VT IPD in infants was observed, although the impact on national IPD incidence varied internationally due to serotype replacement. Currently, NVT serotypes 8, 9N, 15A and 23B are increasing in the countries assessed, although a variety of other NVTs are affecting each country and age group. Despite these common emerging serotypes, there has not been a dominant IPD serotype post-vaccination as there was pre-vaccination (serotype 14) or post-PCV7 (serotype 19A), suggesting that future vaccines with additional serotypes will be less effective at targeting and reducing IPD in global populations than previous PCVs. The rise of diverse NVTs in all settings’ top-ranked IPD-causing serotypes emphasizes the urgent need for surveillance data on serotype distribution and serotype-specific invasiveness post-vaccination to facilitate decision making concerning both expanding current vaccination programmes and increasing vaccine valency.

Incidence of invasive pneumococcal disease after introduction of the 13-valent conjugate pneumococcal vaccine in British Columbia: A retrospective cohort study

BACKGROUND

A significant reduction in invasive pneumococcal disease (IPD) has been reported, across all ages, following the implementation of 7-valent conjugate pneumococcal vaccine (PCV7) globally, as part of infant immunization programs. We explored the additional impact of PCV13 on IPD over a 14-year period.

METHODS

Using provincial laboratory surveillance and hospitalization data (N = 5791), we calculated the annual incidence of IPD following the implementation of PCV13 vaccine. Poisson regression was used to evaluate changes in the overall incidence of IPD, and serotype-specific IPD between PCV7 (2004-10) and PCV13 (2011-2015) eras.

RESULTS

Overall, IPD rates have seen a modest decline in the PCV13 compared to the PCV7 era (IRR 0.84; 95% CI: 0.79-0.89); this was seen in children ≤2 years of age, and the majority of the adult cohort. Rates of vaccine-type IPD (PCV7 and PCV13) also decreased in the PCV13 era. In contrast, IPD incidence related to non-PCV13 (IRR: 1.56; 95%CI:1.43-1.72) and non-vaccine serotypes (IRR: 2.12; 95%CI:1.84-2.45) increased in the PCV13 era compared to the PCV7 era.

CONCLUSIONS

A modest reduction in IPD from the PCV13 vaccine was observed, with gains limited to the immunized cohort and adults. However, a significant increase in non-vaccine serotypes emphasizes the need for continued surveillance.

Emergence of Streptococcus pneumoniae serotype 19A (Spn19A) in the pediatric population in Bogotá, Colombia as the main cause of invasive pneumococcal disease after the introduction of PCV10

Introduction: With the use of pneumococcal conjugate vaccines(PCV), the behavior of invasive pneumococcal disease(IPD) has changed relative to serotype distribution. The introduction of these vaccines in national immunization programs has reduced the incidence of IPD, with a marked decrease in the circulation of the serotypes included in the vaccine used in each country. However, the subsequent emergence of other serotypes not included in the vaccine, such 19A in case of PCV7 and PCV10, has been documented. Materials and methods: This was case series study (2008-2017) in pediatric patients admitted to 10 hospitals in Bogota who were diagnosed with IPD. It was conducted during the transitional period of implementing the PCV10 vaccine in Colombia in 2012. Cases of bacteremic pneumococcal pneumonia, meningitis, primary bacteremia and osteoarticular infection were included. A descriptive analysis of the demographic, clinical and laboratory variables of patients with IPD by Spn19A, its trend over time, profiles of antimicrobial susceptibility and clinical outcomes was performed. Results: There were 463 cases of IPD, 315(68%) with known serotypes. The prevalence of IPD by Spn19A was 17.7%(56 cases), tending to increase over time. During 2008-2011, the prevalence was 4.4%, and during 2014-2017, it was 32.4%, The most frequent diagnosis was pneumonia(80.4%). In nonmeningeal isolates, 39.6% were not susceptible to penicillin. An increase in the resistance was observed over time. Conclusion: Spn19A is a prevalent cause of IPD in the pediatric population of the analyzed cohort, with an increasing trend of this serotype during the surveillance period after the introduction of PCV10, being the most common serotype identified in recent years.

The potential role of pneumococcal conjugate vaccine in reducing acute respiratory inflammation in community-acquired pneumococcal pneumonia

Background

Pneumococcal conjugate vaccine (PCV) reduces both invasive pneumococcal disease (IPD) and other pneumococcal infections worldwide. We investigated the impact of stepwise implementation of childhood PCV programs on the prevalence of pneumococcal pneumonia, severity of acute inflammation, and associations between breakthrough pneumonia and pneumococcal serotypes in Taiwan.

Methods

In total, 983 children diagnosed with community-acquired pneumococcal pneumonia were enrolled between January 2010 and December 2015.

Results

Proportions of pneumococcal vaccinations increased each year in age-stratified groups with PCV7 (32.2%) as the majority, followed by PCV13 (12.2%). The proportion of pneumococcal pneumonia decreased each year in age-stratified groups, especially in 2–5 year group. Serotype 19A is the leading serotype either in vaccinated (6.4%) or unvaccinated patients (5.2%). In particular, vaccinated patients had significantly higher lowest WBC, lower neutrophils, lower lymphocytes and lower CRP values than non-vaccinated patients (p < 0.05). After stratifying patients by breakthrough infection, those with breakthrough pneumococcal infection with vaccine coverage serotypes had more severe pneumonia disease (p < 0.05).

Conclusion

Systematic childhood pneumococcal vaccination reduced the prevalence of community-acquired pneumococcal pneumonia, especially in 2–5 year group. Serotype 19A was the major serotype for all vaccine types in patients with pneumococcal pneumonia and severity of acute inflammatory response was reduced in vaccinated patients.

Impact of the 13-Valent Pneumococcal Conjugate Vaccine Among Adults: A Systematic Review and Meta-analysis

BACKGROUND

A notable reduction of the pneumococcal disease burden among adults was observed after the introduction of a 7-valent pneumococcal conjugate vaccine (PCV7) in childhood immunization programs. In 2010, a 13-valent pneumococcal conjugate vaccine (PCV13) replaced PCV7 in many jurisdictions; a comparative assessment of PCV13's impact was missing. Our objective was to summarize the available data and assess the change in the incidence of invasive pneumococcal disease (IPD) in adults after the introduction of PCV13 in childhood immunization programs.

METHODS

We conducted a systematic literature search from January 1946 to May 2017 of randomized, controlled trials and observational studies OBS reporting the incidence of IPD, non-invasive pneumococcal disease, hospitalizations, and mortality in adults for the periods before and after the introduction of PCV13. Incidence rate ratios (IRRs) were pooled across studies using restricted, maximum-likelihood, random-effects models.

RESULTS

From 3306 records,we included 29 OBS studies and 2033961 cases. Significantly lower IPD rates were seen after PCV13 introduction in adults aged <65 years (IRR 0.78, 95% confidence interval [CI] 0.72-0.85) and those aged ≥65 years (IRR 0.86, 95% CI 0.81-0.91). Lower rates of IPD were seen with PCV7 (IRR 0.45, 95% CI 0.38-0.54) and PCV13 serotypes (IRR 0.60, 95% CI 0.54-0.68). A significantly higher IRR of 1.10 (95% CI 1.04-1.17) for non-vaccine serotypes was observed, especially among those aged 65 years and older (IRR 1.20, 95% CI 1.11-1.29).

CONCLUSIONS

PCV13 use in children had a moderate impact on reducing the overall and vaccine-type IPDs, but there was a significant increase in non-vaccine type IPDs among adults, especially in those over 65 years.

Impact of the 13-Valent Conjugated Pneumococcal Vaccine on the Direct Costs of Invasive Pneumococcal Disease Requiring Hospital Admission in Children Aged < 5 Years: A Prospective Study

The lack of invasive pneumococcal disease (IPD) cost studies may underestimate the eect ofpneumococcal polysaccharide conjugated vaccines (PCV). The objective of this study was to estimatethe direct costs of hospitalized IPD cases. A prospective study was made in children aged <5 yearsdiagnosed with IPD in two high-tech hospitals in Catalonia (Spain) between 2007-2009 (PCV7 period)and 2012-2015 (PCV13 period). Costs were calculated according to 2014 Catalan Health Service ratesusing diagnostic-related groups. In total, 319 and 154 cases were collected, respectively. Pneumoniahad the highest cost (65.7% and 62.0%, respectively), followed by meningitis (25.8% and 26.1%,respectively). During 2007-2015, the costs associated with PCV7 serotypes (Pearson coecient (Pc) =?0.79; p = 0.036) and additional PCV13 serotypes (Pc = ?0.75; p = 0.05) decreased, but those of otherserotypes did not (Pc = 0.23 p = 0.62). The total mean cost of IPD increased in the PCV13 period by31.4% (¿3016.1 vs. ¿3963.9), mainly due to ICU stay (77.4%; ¿1051.4 vs. ¿1865.6). During the PCV13period, direct IPD costs decreased due to a reduction in the number of cases, but cases were more severe and had a higher mean cost. During 2015, IPD costs increased due to an increase in the costsassociated with non-PCV13 serotypes and serotype 3 and this requires further investigation.

Timeliness and completeness of routine childhood vaccinations in young children residing in a district with recurrent vaccine-preventable disease outbreaks, Jerusalem, Israel

BackgroundChildhood vaccination schedules recommend vaccine doses at predefined ages.AimWe evaluated vaccination completeness and timeliness in Jerusalem, a district with recurrent vaccine-preventable disease outbreaks.MethodsVaccination coverage was monitored by the up-to-date method (vaccination completeness at age 2 years). Timeliness of vaccination was assessed in children (n = 3,098, born in 2009, followed to age 48 months, re-evaluated at age 7 years) by the age-appropriate method (vaccine dose timeliness according to recommended schedule). Vaccines included: hepatitis B (HBV: birth, 1 month and 6 months); diphtheria, tetanus, acellular pertussis, polio, Haemophilus influenzae b (DTaP-IPV-Hib: 2, 4, 6 and 12 months); pneumococcal conjugate (PCV: 2, 4 and 12 months); measles-mumps-rubella/measles-mumps-rubella-varicella (MMR/MMRV: 12 months) and hepatitis A (HAV: 18 and 24 months).ResultsOverall vaccination coverage (2014 cohort evaluated at age 2 years) was 95% and 86% for MMR/MMRV and DTaP-IPV-Hib4, respectively. Most children (94%, 91%, 79%, 95%, 92% and 82%) were up-to-date for HBV3, DTaP-IPV-Hib4, PCV3, MMR/MMRV1, HAV1 and HAV2 vaccines at 48 months, but only 32%, 28%, 38%, 58%, 49% and 20% were vaccinated timely (age-appropriate). At age 7 years, the median increase in vaccination coverage was 2.4%. Vaccination delay was associated with: high birth order, ethnicity (higher among Jews vs Arabs), birth in winter, delayed acceptance of first dose of DTaP-IPV-Hib and multiple-dose vaccines (vs MMR/MMRV). Jewish ultra-Orthodox communities had low vaccination coverage.ConclusionsConsiderable vaccination delay should be addressed within the vaccine hesitancy spectrum. Delays may induce susceptibility to vaccine-preventable disease outbreaks; tailored programmes to improve timeliness are required.

Characteristics of Serotype 3 Invasive Pneumococcal Disease before and after Universal Childhood Immunization with PCV13 in Massachusetts

BACKGROUND

Although a substantial decline in vaccine-serotype invasive pneumococcal disease (IPD) incidence was observed following the introduction of pneumococcal conjugate vaccines (PCV), the estimated range of thirteen-valent conjugate vaccine (PCV13) effectiveness for serotype 3 disease is wide and includes zero. We assessed the impact of PCV13 on serotype 3 IPD incidence and disease characteristics in Massachusetts' children.

METHODS

Serotype 3 IPD cases in children <18 years old were identified via enhanced passive surveillance system in Massachusetts. We compared incidence rates and characteristics of IPD cases before and after PCV13.

RESULTS

A total of 47 serotype 3 IPD cases were identified from 2002 to 2017; incidence of serotype 3 IPD in the years following PCV13 was 0.19 per 100,000 children compared to 0.21 before PCV 13, incidence rate ratio (IRR) = 0.86 (95% CI 0.47-1.57). The majority (78%) of post-PCV13 serotype 3 IPD cases occurred among fully vaccinated children. Age distribution, clinical syndrome and presence of comorbidities among serotype 3 IPD cases were similar before and after PCV13 introduction. There was no association between the date of the last PCV13 dose and time to IPD to suggest waning of immunity.

CONCLUSIONS

seven years following PCV 13 we found no significant changes in serotype 3 IPD incidence or disease characteristics in children in Massachusetts.

Pneumococcal conjugate vaccines decrease community-acquired alveolar pneumonia with and without pleural effusion in children <60 months in Southern Israel, 2002-2016

Background: Radiographically-proven community-acquired alveolar pneumonia with pleural effusion (PE-CAP) has a less favourable outcome than pneumonia without pleural effusion (NPE-CAP). We assessed PE-CAP and NPE-CAP rate dynamics in children <60 months in southern Israel before and after 7- and 13-valent pneumococcal conjugate vaccine (PCV7/PCV13) implementation (2002-2016).Methods: An ongoing, prospective observational study. Our hospital serves a captive population of ∼75,000 children <60 months, enabling incidence calculation. PCV7/PCV13 were implemented in Israel in July 2009/November 2010, respectively. All chest radiographs (CXRs) were digitalized and analysed according to the WHO Standardization of Interpretation. Annual incidences of PE-CAP and NPE-CAP were calculated, 2002-2016. Incidence-rate ratios (IRRs) comparing PCV13 (2013-2016), PCV7 (2010-2011) and pre-PCV (2002-2008) periods were calculated.Results: Overall, 12,271 CAP episodes were identified; 159 (1.3%) PE-CAP and 12,112 (98.7%) NPE-CAP. In total, 65.8% and 34.2% were children <24 and 24-59 months, respectively; 61.0% and 39.0% were Bedouin and Jewish children, respectively. Following PCV7 introduction, PE-CAP rates declined by 48% (Incidence rate ratios [IRR] = 0.52; 0.26-1.03), while NPE-CAP rates declined by 20% (IRR = 0.80; 0.75-0.86). In the PCV13 period, PE-CAP and NPE-CAP rates further declined, resulting in overall 70% (IRR = 0.30; 0.18-0.50) and 55% (IRR = 0.45; 0.43-0.48) reductions, respectively, comparing the PCV13 and the pre-PCV periods. Similar trends were observed in all subgroups (Bedouin vs. Jewish and age < 24 months vs. 24-59 months).Conclusions: Following PCV7/PCV13 introduction, PE-CAP and NPE-CAP rates substantially declined. However, the rate dynamics were different, with steeper declines observed in PE-CAP rates, possibly deriving from differences in disease aetiology.

Impact of pneumococcal conjugate vaccines introduction on antibiotic resistance of Streptococcus pneumoniae meningitis in children aged 5 years or younger, Israel, 2004 to 2016

Background

Empiric treatment of pneumococcal meningitis includes ceftriaxone with vancomycin to overcome ceftriaxone resistant disease. The addition of vancomycin bears a risk of adverse events, including increased antibiotic resistance. We assessed antibiotic resistance rates in pneumococcal meningitis before and after pneumococcal conjugate vaccine (PCV) implementation.

Methods

All pneumococcal meningitis episodes in children aged 5 years and younger, from 2004 to 2016, were extracted from the nationwide bacteremia and meningitis surveillance database. For comparison purposes, we defined pre-PCV period as 2004–2008 and PCV13 period as 2014–2016. Minimal inhibitory concentration (MIC) > 0.06 and > 0.5 μg/mL were defined as penicillin and ceftriaxone resistance, respectively.

Results

Overall, 325 episodes were identified. Pneumococcal meningitis incidence rates declined non-significantly by 17%, comparing PCV13 and pre-PCV periods. Throughout the study, 90% of isolates were tested for antibiotic susceptibility, with 26.6%, 2.1% and 0% of isolates resistant to penicillin, ceftriaxone and vancomycin, respectively. Mean proportions (± SD) of meningitis caused by penicillin-resistant pneumococci were 40.5% ± 8.0% and 9.6% ± 7.4% in the pre-PCV and the PCV13 periods, respectively, resulting in an overall 83.9% reduction (odd ratio:0.161; 95% confidence interval: 0.059–0.441) in penicillin resistance rates. The proportions of meningitis caused by ceftriaxone resistant pneumococci were 5.0% ± 0.8% in the pre-PCV period, but no ceftriaxone resistant isolates were identified since 2010.

Conclusions

PCV7/PCV13 sequential introduction resulted in > 80% reduction of penicillin- resistant pneumococcal meningitis and complete disappearance of ceftriaxone resistant disease. These trends should be considered by the treating physician when choosing an empiric treatment for pneumococcal meningitis.

Relationship between immune response to pneumococcal conjugate vaccines in infants and indirect protection after vaccine implementation

Introduction: Streptococcus pneumoniae is a leading cause of morbidity and mortality worldwide. Widespread infant vaccination with pneumococcal conjugate vaccines (PCVs) substantially reduced vaccine-serotype pneumococcal disease by direct protection of immunized children and indirect protection of the community via decreased nasopharyngeal carriage and transmission. Essential to grasping the public health implications of pediatric PCV immunization is an understanding of how PCV formulations impact carriage. Areas covered: Using clinical evidence, this review examines how the immune response to PCVs is associated with subsequent nasopharyngeal carriage reduction in vaccinated infants and toddlers. By combining direct and indirect protection, carriage reduction results in a reduced spread of vaccine serotypes, and eventually, a decrease in vaccine serotype disease incidence in community members of all ages. Expert opinion: The current review presents some of the aspects that influence the overall impact of PCVs on vaccine-serotype carriage, and thus, spread. The link between reduction of vaccine-serotype carriage and the eventual reduction of vaccine-serotype disease in the wider community is described by comparing data from current PCVs, specifically with respect to their ability to reduce carriage of some cross-reacting serotypes (i.e. 6A versus 6B and 19A versus 19F).

Cost-Effectiveness Comparison of Pneumococcal Conjugate Vaccines in Turkish Children

BACKGROUND

The 13-valent pneumococcal conjugate vaccine (PCV13) is used for universal infant vaccination in Turkey.

OBJECTIVES

To assess the cost effectiveness of replacing PCV13 with pneumococcal nontypeable Haemophilus influenzae protein D conjugate vaccine (PHiD-CV).

METHODS

A Markov cohort model with monthly cycles following 1 cohort of infants over a 10-year time horizon was used. Local input parameters were obtained from published sources and expert consultation whenever possible. The model was adapted to estimate the health benefits and economic impact of each vaccine on invasive pneumococcal disease, pneumonia, and acute otitis media (AOM). An annual discount rate of 3% was used for benefits and costs (2016 euros).

RESULTS

Under base-case assumptions, vaccinating 1 birth cohort of 1 325 783 infants with PHiD-CV instead of PCV13 was predicted to have the same impact on meningitis and pneumonia, a similar impact on bacteremia (+30 cases), but greater reductions in AOM-related general practitioner visits (-34 955) and hospitalizations (-624). Assuming equal vaccine prices, PHiD-CV was predicted to be dominant over PCV13 (176 additional quality-adjusted life-years while saving €635 330 [discounted]). One-way sensitivity analysis indicated that varying the vaccine price differential had the largest effect on the incremental cost-effectiveness ratio, and then AOM parameters. Probabilistic sensitivity analysis predicted PHiD-CV to be dominant over PCV13 in 92.4% of simulations.

CONCLUSIONS

Any difference in price between PHiD-CV and PCV13 is expected to be the key driver of vaccine choice for preventing childhood pneumococcal disease in Turkey. At price parity, PHiD-CV use is likely to be a dominant strategy over the use of PCV13.

Why is the rate of pneumococcal pneumonia declining?

PURPOSE OF REVIEW

As Streptococcus pneumoniae was considered the etiological agent of nearly all the cases of pneumonia at the beginning of the 20th century, and today is identified in fewer than 10-15% of cases, we analyze the possible causes of such a decline.

RECENT FINDINGS

Extensive use of early empiric antimicrobial therapy, discovery of previously unrecognized pathogens, availability to newer diagnostic methods for the recognition of the pneumonia pathogens (PCR, urinary antigens, monoclonal antibodies etc.) and of improved preventive measures, including vaccines, are some of possible explanations of the declining role of S. pneumoniae in the cause of pneumonia.

SUMMARY

The 14-valent and the 23-valent capsular polysaccharide pneumococcal vaccines were licensed in 1977 and 1983, respectively. The seven-valent protein-conjugated capsular polysaccharide vaccine, approved for routine use in children starting at 2 months of age, was highly effective in preventing invasive pneumococcal disease in children but also in adults because of the herd effect. In 2010, the 13-valent protein-conjugated capsular polysaccharide vaccine replaced seven-valent protein-conjugated capsular polysaccharide vaccine. With the use of conjugated vaccines, a decrease of the vaccine-type invasive pneumococcal disease for all age groups was observed. Both the direct effect of the vaccine and the so-called herd immunity are considered responsible for much of the decline.

Emergence of Streptococcus pneumoniae Serotype 12F after Sequential Introduction of 7- and 13-Valent Vaccines, Israel

Israel implemented use of 7- and 13-valent pneumococcal vaccine in 2009 and 2010, respectively. We describe results of prospective, population-based, nationwide active surveillance of Streptococcus pneumoniae serotype 12F (Sp12F) invasive pneumococcal disease (IPD) dynamics in the 7 years after vaccine introduction. Of 4,573 IPD episodes during July 2009-June 2016, a total of 434 (9.5%) were caused by Sp12F. Sp12F IPD rates (cases/100,000 population) increased in children <5 years of age, from 1.44 in 2009-2010 to >3.9 since 2011-2012, followed by an increase in all ages. During 2011-2016, Sp12F was the most prevalent IPD serotype. Sp12F isolates were mostly penicillin nonsusceptible (MIC >0.06 µg/mL; MIC₅₀ = 0.12) and predominantly of sequence type 3774), a clone exclusively found in Israel (constituting ≈90% of isolates in 2000-2009). The sharp increase, long duration, and predominance of Sp12F IPD after vaccine implementation reflect a single clone expansion and may represent more than a transient outbreak.

Validation of a Multiplexed Opsonophagocytic Assay for 11 Additional Pneumococcal Serotypes and Its Application to Functional Antibody Evaluation Induced by Pneumococcal Polysaccharide Vaccine

BACKGROUND

Various pneumococcal vaccines have been evaluated for immunogenicity by opsonophagocytic assay (OPA). A multiplexed OPA (MOPA) for 13 pneumococcal serotypes was developed by Nahm and Burton, and expanded to 26 serotypes in 2012. The development of new conjugate vaccines with increased valence has necessitated expanded MOPAs to include these additional serotypes. In this study, we validated this expanded MOPA platform and applied to measure antibodies against 11 additional serotypes (2, 8, 9N, 10A, 11A, 12F, 15B, 17F, 20B, 22F, and 33F) in human sera.

METHODS

All materials, including serum, complement, bacterial master stocks, and HL-60 cells, were evaluated for assay optimization. Following optimization, the assay was validated for accuracy, specificity, and intra- and inter-assay precision with sera from adult donors following standard protocols. The assay was applied to evaluate functional antibodies of 42 sera immunized with 23-valent pneumococcal polysaccharide vaccine (PPV23).

RESULTS

The expanded MOPA platform was specific for all serotypes, with the exception of serotype 20. The assay results were highly correlated with those obtained from single-serotype OPA, indicating acceptable accuracy. The coefficients of variation were 7%-24% and 13%-39% in tests of intra- and inter-assay precision, respectively, using three quality-control samples. A MOPA that included 11 additional serotypes in the PPV23 was established and validated with respect to accuracy, specificity, and precision. The opsonic indices of immune sera were obtained using this validated assay.

CONCLUSION

The expanded MOPA will be useful for evaluation of the immunogenicity of PPV23 and future conjugate vaccine formulations.

Serotype-Specific IgG Antibody Waning after Pneumococcal Conjugate Primary Series Vaccinations with either the 10-Valent or the 13-Valent Vaccine

The two currently available ten- and thirteen-valent pneumococcal conjugate vaccines (PCV10 and PCV13) both induce serotype-specific IgG anti-polysaccharide antibodies and are effective in preventing vaccine serotype induced invasive pneumococcal disease (IPD) as well as in reducing overall vaccine-serotype carriage and transmission and thereby inducing herd protection in the whole population. IgG levels decline after vaccination and could become too low to prevent carriage acquisition and/or pneumococcal disease. We compared the levels of 10-valent (PCV10) and 13-valent (PCV13) pneumococcal vaccine induced serum IgG antibodies at multiple time points after primary vaccinations. Data from two separate studies both performed in the Netherlands in infants vaccinated at 2, 3, and 4 months of age with either PCV10 or PCV13 were compared. Antibody levels were measured at 5, 8, and 11 months of age, during the interval between the primary immunization series and the 11-months booster dose. Serotype-specific IgG levels were determined by multiplex immunoassay. Although antibody kinetics showed significant variation between serotypes and between vaccines for the majority of the 10 shared serotypes, i.e., 1, 5, 7F, 9V, 14, 18C, and 23F, antibody concentrations were sufficiently high for both vaccines, immediately after the primary series and throughout the whole period until the booster dose. In contrast, for serotypes 4 and 19F in the PCV10 group and for serotypes 4 and 6B in the PCV13 group, IgG antibody concentrations already come within reach of the frequently used seroprotection level of 0.35 μg/mL immediately after the primary series at the five month time point and/or at eight months. This paper addresses the importance of revealing differences in serotype-specific and pneumococcal vaccine-dependent IgG antibody patterns during the interval between the primary series and the booster dose, an age period with a high IPD incidence. Trial registration: www.trialregister.nl NTR3069 and NTR2316.

Cost-Effectiveness of the Pneumococcal Conjugate Vaccine (10- or 13-Valent) Versus No Vaccination for a National Immunization Program in Tunisia or Algeria

INTRODUCTION

To evaluate the expected impact of the Algeria national immunization program (NIP) and potential impact for a Tunisia NIP, this study assessed the public health and economic value of vaccination, through a cost-effectiveness analysis, for a PCV13 or PCV10 NIP, compared with no vaccination.

METHODS

A decision-analytic model was programmed in Microsoft Excel™ and adapted to evaluate the clinical and economic outcomes of PCV vaccination. Assuming a steady state, the model estimated invasive pneumococcal disease (IPD; bacteremia and meningitis), all-cause pneumonia (inpatient and outpatient), and all-cause otitis media cases as well as the associated costs from a payer perspective. The base case scenario assumed direct effects for both PCVs and indirect effects (against IPD) for PCV13 only.

RESULTS

In Algeria, compared with no vaccination program, PCV13 would save 2177 lives and avoid nearly 349,000 cases of IPD, pneumonia, and AOM at a highly cost-effective value of $308 per QALY. In Tunisia, PCV13 would save 308 lives and avoid 1305 cases of IPD, 4833 cases of pneumonia, and 54,957 cases of AOM at a highly cost-effective value of $848 per QALY. PCV10 prevented 1224 deaths and 270,483 cases of disease in Algeria and prevented 172 deaths and 56,610 cases in Tunisia. PCV10 was cost-effective in both Algeria at $731/QALY and in Tunisia at $1366/QALY.

CONCLUSION

The ongoing NIP in Algeria is projected to reduce the impact and economic toll of pneumococcal disease in Algeria. If an NIP were also introduced in Tunisia, a commensurate impact would be expected. PCV NIPs are highly cost-effective, highly impactful public health interventions.

FUNDING

Pfizer.

Comparison of early effects of pneumococcal conjugate vaccines: PCV7, PCV10 and PCV13 on Streptococcus pneumoniae nasopharyngeal carriage in a population based study; The Palestinian-Israeli Collaborative Research (PICR)

Background

Pneumococcal conjugate vaccines (PCVs), PCV10 and PCV13, are currently used in different countries. We have previously reported the effectiveness of PCV7, following its introduction in Israel and before PCVs were introduced in Palestine. Here, we extended the study and compared the initial impact of PCV10 to that of PCV7/13.

Methods

Four cross-sectional surveys of S. pneumoniae carriage among children <5y through 2009–2014 were preformed among two proximate populations, living under two distinct health authorities, with different vaccination policies. In East-Jerusalem (EJ), PCV7 was implemented in 2009 and replaced by PCV13 in late 2010, while in Palestine (PA), PCV10 was implemented in 2011.

Results

A total of 1267 and 2414 children from EJ and PA were screened. In 2014, S. pneumoniae was detected in 30.7% and 28.6% of the children in EJ and PA respectively Implementation of both PCV7 (in EJ) and PCV10 (in PA) did not affect overall S. pneumoniae carriage, but resulted in a significant decrease in the prevalence of vaccine-type strains. In the pre-vaccine era, VT7/VT13 strains consisted 47.0%/62.0% and 41.2%/54.8% of pneumococci in EJ and PA, respectively. A 48.6% and 53.9% decrease in VT7 strains was observed within 3 years of PCV7 implementation in EJ (p = 0.001) and PCV10 in PA (p<0.0001), respectively. These vaccination policies also resulted in ~50% reduction in VT13-added serotypes especially 6A (from 11.0% to 0.0% (EJ) and 9.5% to 4.9% (PA)). Three years after PCV13 implementation in EJ, an additional 67% decrease in VT13 strains was observed, yet an increase in serotype 3 was observed (0.0% to 3.4%, p = 0.056). While the prevalence of VT13 strains decreased significantly during the study period, the overall carriage rate didn’t change significantly due to replacement with non-VT13 strains which comprised 89.8% and 70.7% of all pneumococci, in EJ and in PA respectively in the last study year.

Conclusions

Within the first three years following PCV implementation, we observed similar reductions in carriage of VT10 and VT13 strains with either vaccination policies, with no effect on overall carriage. Further follow-up is needed to compare the long-term effects.

Dynamics of Severe and Non-severe Invasive Pneumococcal Disease in Young Children in Israel Following PCV7/PCV13 Introduction

BACKGROUND

The introduction of the pneumococcal conjugated vaccines (PCVs) resulted in a substantial reduction of invasive pneumococcal disease (IPD) rates. However, impact on nonsevere IPD (mostly occult bacteremia) has not yet been fully elucidated. We assessed severe and nonsevere IPD (SIPD and NSIPD, respectively) rate dynamics in children < 5 years in Israel before and after PCV7/PCV13 implementation.

METHODS

A prospective, population-based, nationwide surveillance. All IPD episodes recorded from 1999 through 2015 were included. NSIPD was defined as IPD episodes without meningitis, pneumonia or mastoiditis in a child with a favorable outcome (not hospitalized or hospitalized in a nonintensive care unit < 5 days, without mortality). Three subperiods were defined: pre-PCV (1999-2008), PCV7 (2010-2011) and PCV13 (2013-2015). Incidence rate ratios (IRRs) were calculated.

RESULTS

Overall, 4,457 IPD episodes were identified; 3,398 (76.2%) SIPD, 1,022 (22.9%) NSIPD and 37 (0.8%) unknown. In 90% of NSIPD episodes, no focus was identified. In the PCV7 period, NSIPD rates significantly declined by 52%, while SIPD rates declined less prominently by 24%. Following PCV13 introduction, compared with the PCV7 period, NSIPD rates declined nonsignificantly by 17% while SIPD rates declined significantly further by an additional 53%. These trends resulted in overall reductions (comparing PCV13 and pre-PCV periods) of NSIPD and SIPD of 60% (IRR = 0.4; 0.32-0.51) and 64% (IRR = 0.36; 0.32-0.42), respectively.

CONCLUSIONS

Following PCV7/PCV13 introduction, SIPD and NSIPD rates substantially declined, with differences in rate-dynamics, alluding to differences in serotype distribution between the 2 groups. Future surveillance is warranted when considering modification in treatment protocols for suspected occult bacteremia/NSIPD cases.

Safety and immunogenicity of 15-valent pneumococcal conjugate vaccine (PCV15) in healthy infants

BACKGROUND

Pediatric use of pneumococcal conjugate vaccines (PCV) has been associated with significant decrease in disease burden. However, disease caused by non-vaccine serotypes has increased. Safety and immunogenicity of 15-valent PCV (PCV15) containing serotypes included in 13-valent PCV (PCV13) plus serotypes 22F and 33F were evaluated in infants (NCT01215188).

METHODS

Infants received adjuvanted PCV15, nonadjuvanted PCV15, or PCV13 at 2, 4, 6, and 12-15 months of age. Safety was monitored for 14 days after each dose. Serotype-specific IgG geometric mean concentrations (GMCs) and opsonophagocytic activity (OPA) geometric mean titers (GMTs) were measured at postdose-3, predose-4, and postdose-4.

RESULTS

Safety profiles were comparable across vaccination groups. At postdose-3, both PCV15 formulations were non-inferior to PCV13 for 10 of 13 shared serotypes but failed non-inferiority for 3 serotypes (6A, 6B, and 19A) based on proportion of subjects achieving IgG GMC ≥0.35 µg/mL. Adjuvanted PCV15 and nonadjuvanted PCV15 were non-inferior to PCV13 for 11 and 8 shared serotypes, respectively, based on postdose 3 comparisons of GMC ratios. PCV15 induced higher antibodies to serotypes 3, 22F, and 33F than PCV13.

CONCLUSIONS

PCV15 displayed acceptable safety profile and induced IgG and OPA to all 15 vaccine serotypes at levels comparable to PCV13 for 10 of 13 shared serotypes. Study identification: V114-003. CLINICALTRIALS.GOV identifier: NCT01215188.