Impact of introduction of conjugate vaccines in the vaccination schedule on the incidence of pediatric invasive pneumococcal disease requiring hospitalization in Madrid 2007 to 2011

Complicated pneumococcal pneumonia in the era of higher-valent pneumococcal conjugate vaccines: a systematic literature review and meta-analysis, 2001-2022

PURPOSE

To estimate pneumococcal conjugate vaccine (PCV) national program impact on pneumococcal complicated pneumonia (PnCP) based on changes in PnCP population-based incidence, PnCP proportion of all-cause complicated pneumonia (or invasive pneumococcal disease), and PnCP serotype distribution.

METHODS

MEDLINE, EMBASE, and Global Index Medicus articles (2001-March 2022) reporting laboratory-confirmed PnCP studies were stratified by age group, outcome measure, PCV program period(s) (pre-PCV, transition, and post-PCV), serotype distribution (based on serotyping methodology used), and PCV serotype formulation. Random effect meta-analysis of the total number of serotyped isolates within each study was used to calculate pooled serotype-specific percentages.

RESULTS

Of 1360 publications screened, the 134 studies included from 30 countries differed widely by methodological approaches. Pediatric PnCP incidence tended to decline from pre-PCV to post-PCV periods, as did PnCP as a proportion of all-cause complicated pneumonia from transition to post-PCV periods. Studies describing changes in serotype distribution by PCV program period applied detection methods that varied from pre-PCV period microbiological culture with Quellung serotyping to in the transition and post-PCV periods molecular methods like PCR. Meta-analysis revealed near elimination of pediatric PCV7-serotype PnCP between pre- and post-PCV, while the PCV13nonPCV7 percentage increased from 51.1% pre-PCV period to 76.5% in the transition period, remaining stable post-PCV period. Non-PCV13 serotypes increased slightly from low baseline numbers. Adult data were lacking or inconsistent.

CONCLUSIONS

Although studies were heterogeneous, pediatric PnCP incidence and proportion tended to decline from pre-PCV to post-PCV periods, and PCV13nonPCV7 serotype distribution percentage remained unchanged from transition to post-PCV period. Standardization of PnCP surveillance methods, definitions, and reporting is needed to evaluate accurately PCV program impact.

Surveillance of pediatric parapneumonic effusion/empyema in New Zealand

AIM

The incidence of childhood empyema has been increasing in some developed countries despite the introduction of pneumococcal vaccination. This study aimed to document the incidence, bacterial pathogens, and morbidity/mortality of parapneumonic effusion/empyema in New Zealand.

METHODS

A prospective study of 102 children <15 years of age requiring hospitalization with parapneumonic effusion/empyema between May 1, 2014 and May 31, 2016 notified via the New Zealand Paediatric Surveillance Unit. Parapneumonic effusion/empyema was defined as pneumonia and pleural effusion persisting ≥7 days, and/or any pneumonia, and pleural effusion necessitating drainage. Notifying pediatricians completed standardized questionnaires.

RESULTS

Annual pediatric parapneumonic effusion/empyema incidence was 5.6/100,000 (95% confidence interval [CI]: 4.7-6.9). Most children (80%) required surgical intervention and 31% required intensive care. A causative organism was identified in 71/102 (70%) cases. Although Staphylococcus aureus (25%) and Streptococcus pneumoniae (25%) infection rates were equal, prolonged hospitalization and intensive care admission were more common in children with S. aureus PPE/E. Māori and Pasifika children were over-represented at 2.2 and 3.5 times, their representation in the New Zealand pediatric population. Pneumococcal vaccination was incomplete, with only 61% fully immunized and 30% unimmunized. Haemophilus influenzae type b vaccine uptake was near complete at 89/94 (95%), with influenza immunization only 3/78 (4%).

CONCLUSIONS

New Zealand has a high incidence of pediatric complicated parapneumonic effusion/empyema with significant morbidity. S. aureus was a significant cause of severe empyema in New Zealand, particularly for Māori and Pasifika children. Improvements in vaccine coverage are needed along with strategies to reduce S. aureus disease morbidity.

Complications in community acquired pneumonia: magnitude of problem, risk factors, and management in pediatric age

Introduction: In the last decades, the large use of several effective vaccines has dramatically reduced the incidence of community acquired pneumonia (CAP) in infants and children. Moreover, the availability of new antibiotics effective against emerging resistant strains of bacteria has greatly improved the early and long-term prognosis of this disease.Areas covered: The aim of this manuscript is to evaluate the burden of complicated CAP in pediatric age and to discuss its appropriate management.Expert opinion: Complicated CAP remains a problem for children in industrialized and developing countries. A larger use of lung ultrasonography (US) as first diagnostic approach could significantly improve early identification of cases at higher risk of complications. Difficult to solve, is the problem of the use of an antibiotic therapy able to assure adequate control in all the CAP cases, including those at high risk of or with already established complications. All these findings reveal that control of the incidence of complicated CAP remains difficult and will not be significantly changed in the next few years. Any attempt to improve complicated CAP management must be made. Consensus documents on better definition of the use of corticosteroids, fibrinolytic agents, and interventional procedures (including surgery) can allow us to reach this goal.

A systematic literature review of economic evaluations of pneumococcal conjugate vaccines in east and southeast Asia (2006-2019)

INTRODUCTION

Pneumococcal infections can lead to serious invasive diseases such as meningitis, septicemia and pneumonia, as well as milder but more common illnesses such as sinusitis and otitis media. The World Health Organization (WHO) recommends the inclusion of pneumococcal conjugate vaccines (PCVs) in infant National Immunization Program (NIP) programs worldwide. Decision-makers in Asian countries planning to introduce PCVs in their respective NIP will need a comprehensive evidence of effectiveness of PCVs at the population level and economic evidence including cost-effectiveness.

AREAS COVERED

A systematic literature review (from 1/1/2016 to 10/11/2019) of PCVs in East and Southeast Asia to understand (1) the contributing factors to cost-effectiveness results of PCVs and (2) whether gaps in evidence exist suggesting why the region may have yet to implement full NIPs.

EXPERT OPINION

In East and Southeast Asia, vaccination with PCVs was found to significantly reduce the mortality and morbidity of pneumococcal diseases and was cost-effective compared to no vaccination. Study assumptions, specifically vaccine local acquisition, the inclusion or exclusion of indirect effects (serotype replacement and herd effect), cross-protection, and protection against nontypeable haemophilus influenzae and serotype 3, were the main drivers of cost-effectiveness.

Assessing the impact of the 13 valent pneumococcal vaccine on childhood empyema in Australia

BACKGROUND

Empyema is a serious complication of pneumonia frequently caused by Streptococcus pneumoniae (SP). We assessed the impact of the 13-valent pneumococcal conjugate vaccine (13vPCV) on childhood pneumonia and empyema after inclusion in the Australian National Immunisation Program.

METHODS

For bacterial pneumonia and empyema hospitalisations, we ascertained incidence rates (IRs) using the National Hospital Morbidity Database International Statistical Classification of Disease discharge codes and relevant population denominators, and calculated incidence rate ratios (IRR) comparing the 13vPCV period (June 2012-May 2017) with the 7vPCV period (June 2007-May 2011). Blood and pleural fluid (PF) cultures and PF PCR of 401 children with empyema from 11 Australian hospitals during the 13vPCV period were compared with our previous study in the 7vPCV period.

FINDINGS

Across 7vPCV and 13vPCV periods, IRs per million children (95% CIs) were 1605 (1588 to 1621) and 1272 (1259 to 1285) for bacterial pneumonia, and 14.23 (12.67 to 15.79) and 17.89 (16.37 to 19.42) for empyema hospitalisations. IRRs were 0.79 (0.78 to 0.80) for bacterial pneumonia and 1.25 (1.09 to 1.44) for empyema. Of 161 empyema cases with SP serotypes, 147 (91.3%) were vaccine types. ST3 accounted for 76.4% of identified serotypes in the 13vPCV period, more than double than the 7vPCV period (p<0.001); ST19A decreased from 36.4% to 12.4%. No cases of ST1 empyema were identified in the 13vPCV period versus 14.5% in the 7vPCV period.

INTERPRETATION

13vPCV resulted in a significant reduction in all-cause hospitalisations for bacterial pneumonia but empyema hospitalisations significantly increased, with emergence of pneumococcal ST3 as the dominant serotype in empyema.

TRIAL REGISTRATION NUMBER

Australian and New Zealand Clinical Trial Registry ACTRN 12614000354684.

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.

Serotype evolution in Western Europe: perspectives on invasive pneumococcal diseases (IPD)

Introduction: Epidemiologic trends for IPD have evolved with the introduction of pneumococcal conjugate vaccines into childhood immunization programs. We document the ongoing impact of PCV programs in 15 Western European countries.Areas covered: Data were collected from relevant published observational studies and national surveillance websites from January 2010 through January 2018. In countries using PCV13, the proportion of IPD due to PCV13 serotypes declined significantly (from 60-78% to 8-26%) in children <5 years of age within 5-8 years following vaccine introduction. In countries using PCV10, a marked decrease in PCV10-serotype IPD was reported; however, the proportion of IPD due to PCV13 serotypes remained high at 58-64%, predominantly due to serotypes 19A and 3.Expert opinion: The prevalence of vaccine-type IPD in adults remained high; emerging non-vaccine serotypes such as 8, 12F, 22F, 33F, and 15B/C should be a focus of future vaccine development.

Pneumococcal Vaccination and Pneumonia Associated With Pleural Effusion in a Pediatric Population

OBJECTIVE

The aim was to assess the effect of the nonsystematic pneumococcal conjugate vaccine (PCV) on incidence of pneumonia associated with parapneumonic pleural effusion (PPE) in vaccinated and unvaccinated children.

METHODS

Cases were patients <15 years of age who had been diagnosed with pneumonia associated with PPE in a tertiary hospital in Navarra (Spain) between 1995 and 2014. The population <15 years of age and covered by the public health service was used as reference. The vaccination status of the cases and population was obtained from computerized medical records. Logistic regression analyses included vaccination status, age group and time periods: prevaccine (1995-2001) and vaccination with PCV7 (2002-2010) and PCV13 (2011-2014).

RESULTS

A total of 321 cases of PPE were included. The risk of PPE increased between the prevaccine and PCV7 period (adjusted odds ratio [OR], 3.34; 95% confidence interval [CI]: 2.37-4.71), while vaccination with PCV7 was found to be an independent risk factor (OR, 1.44; 95% CI: 1.09-1.89) in the same analysis. In the PCV13 period, the risk of PPE returned to the prevaccination incidence level among children vaccinated with PCV13 (OR, 1.07; 95% CI: 0.56-2.04), while unvaccinated children (OR, 1.69; 95% CI: 0.96-2.98) and overall those vaccinated with PCV7 (OR, 3.64; 95% CI: 2.15-6.17) maintained an increased risk of PPE.

CONCLUSION

The nonsystematic introduction of PCV7 was followed by an increased incidence of PPE. The subsequent introduction of PCV13 was associated with a return to the incidence level in the prevaccine period, mainly in children vaccinated with PCV13.

Decrease of invasive pneumococcal disease (IPD) in adults after introduction of pneumococcal 13-valent conjugate vaccine in Spain

A prospective laboratory-based multicenter study that collected all adult invasive pneumococcal disease (IPD) episodes from 6 Spanish hospitals before (2008-2009) and after (2012-2013). The 13-valent pneumococcal conjugate vaccine (PCV13) licensure was conducted in order to analyze the impact of PCV13 introduction for children on adult IPD. A total of 1558 IPD episodes were detected. The incidence of IPD decreased significantly in the second period by -33.9% (95% CI, -40.3% to -26.8%). IPD due to PCV7 serotypes (-52.7%; 95% CI, -64.2% to -37.5%) and to PCV13 additional serotypes (-55.0% 95% CI, -62.0% to -46.7%) significantly decreased whereas IPD due to non-PCV13 serotypes remained stable (1.0% 95% CI, -12.9% to 17.2%). IPD due to all PCV13 additional serotypes significantly declined with the exception of serotype 3 (-11.3%; 95%CI -35.0% to 21.1%). IPD due to two non-PCV13 serotypes varied: serotype 6C that rose (301.6%; 95%CI, 92.7% to 733.3%, p<0.001), related to the expansion of ST3866C, and serotype 8 that decreased (-34.9%, 95%CI, -57.1 to -1.2, p = 0.049), related to a decline of the ST638. The recombinant clone ST652111A (variant of ST1569V) increased in frequency. The decrease of serotype 19A IPD was linked to a fall in those antibiotic susceptible clones. In the last period, rates of penicillin- and cefotaxime-resistance remained under 10% and 4%, respectively. Adult IPD decreased after the PCV13 introduction in Spain due to herd protection. The spread of multidrug resistant clones (ST3866C, ST652111A) related to non-PCV13 serotypes needs further surveillance.

Effect of the different 13-valent pneumococcal conjugate vaccination uptakes on the invasive pneumococcal disease in children: Analysis of a hospital-based and population-based surveillance study in Madrid, Spain, 2007-2015

In the Community of Madrid, the 13-valent pneumococcal conjugate vaccine (PCV13) replaced the 7-valent (PCV7) in the fully government-funded Regional Immunization Program (RIP) in May, 2010, but was later excluded in May, 2012, and included again in January, 2015. These unique changes allowed us to assess the impact of the different pneumococcal vaccination policies on PCV13 uptake in infants and on the incidence rate (IR) of invasive pneumococcal disease (IPD) in children <15 years old. In this prospective, active, surveillance study, we estimated PCV13 uptakes, IR and incidence rate ratios (IRR) for total IPD and for IPD caused by PCV13- and non-PCV13 serotypes in children <15 years, stratified by age, in four periods with different vaccination policies: fully government-funded PCV7 vaccination, fully government-funded PCV13, mixed public/private funding and only private funding. Vaccine uptakes reached 95% in periods with public-funded pneumococcal vaccination, but fell to 67% in the private funding period. Overall, IR of IPD decreased by 68% (p<0.001) in 2014–15, due to 93% reduction in the IR of PCV13-type IPD (p<0.001) without significant changes in non-PCV13-type IPD. A fully government-funded PCV13 vaccination program lead to high vaccine uptake and dramatic reductions in both overall and PCV13-type IPD IR. When this program was switched to private PCV13 vaccination, there was a fall in vaccine coverage and stagnation in the decline of PCV13-type IPD with data suggesting a weakening of herd immunity.

A reflection on invasive pneumococcal disease and pneumococcal conjugate vaccination coverage in children in Southern Europe (2009-2016)

Higher-valent pneumococcal conjugate vaccines (PCVs) were licensed from 2009 in Europe; similar worldwide clinical effectiveness was observed for PCVs in routine use. Despite a proven medical need, PCV vaccination in Southern Europe remained suboptimal until 2015/16.

We searched PubMed for manuscripts published between 2009 and mid-2016. Included manuscripts had to contain data about invasive pneumococcal disease (IPD) incidence, or vaccination coverage with higher-valent PCVs. This review represents the first analysis of vaccination coverage and impact of higher-valent PCVs on overall IPD in Southern European countries (Portugal, Spain, Italy, Greece, Cyprus).

Vaccination coverage in the Portuguese private market peaked around 2008 at 75% (children ≤ 2 years) but declined to 63% in 2012. In Madrid, coverage was 95% (2007–2012) but dropped to 67% (2013/14; children ≤ 2 years) after funding termination in May 2012. PCVs were recently introduced in the national immunisation program (NIP) of Portugal (2015) and Spain (2015/16). In Italy, coverage for the complete PCV schedule (children ≤ 2 years) was 88% in 2013, although highly variable between regions (45–99%). In Greece, in 2013, 82.3% had received 3 PCV doses by 12 months, while 62.3% received the fourth dose by 24 months. Overall IPD (net benefit: effect on vaccine types, vaccine-related types, and non-vaccine types) has decreased; in Greece, pneumococcal meningitis incidence remained stable.

Continued IPD surveillance or national registers using ICD-10 codes of clinically suspected IPD are necessary, with timely publicly available reports and adequate national vaccination registers to assess trends in vaccination coverage, allowing evaluation of PCVs in NIPs.

Changes in empyema among U.S. children in the pneumococcal conjugate vaccine era

BACKGROUND

Parapneumonic empyema, a serious complication of pneumonia, started increasing among U.S. children before the introduction of the 7-valent pneumococcal conjugate vaccine (PCV7) in 2000, and continued afterwards. This increase was due in part to pneumococcal serotypes not included in PCV7 that were included in the new 13-valent (PCV13) vaccine introduced in 2010. We assessed changes in the incidence of empyema hospitalizations among U.S. children after PCV13 introduction.

METHODS

We calculated annualized empyema hospitalization rates among U.S. children <18years using Nationwide Inpatient Sample and Census data (1997-2013) for four periods based on PCV7 and PCV13 introductions. Relative rates (RR) and 95% confidence intervals (CI) were calculated by age group and sex, comparing PCV7 [early-PCV7 (2001-2005) and late-PCV7 (2006-2009)] and PCV13 (2011-2013) periods with the pre-PCV7 period (1997-1999). Secondary analyses examined changes in pneumococcal, streptococcal, staphylococcal and unspecified empyema.

RESULTS

Among children <18years of age, annualized empyema hospitalization rates peaked at 3.6 per 100,000 in the late-PCV7 period compared with 2.1 per 100,000 in the pre-PCV7 period [RR: 1.70 (95% CI: 1.11-2.60)]. However, annualized rates in the post-PCV13 period declined to 2.0 per 100,000, similar to rates in the pre-PCV7 period. Empyema rates among children <2years were lower in the post-PCV13 period compared to the pre-PCV7 period [RR: 0.77 (95% CI: 0.61-0.96)], but rates in the two periods among children 2-4 and 5-17years were similar. Most empyema were of unspecified etiology. Pneumococcal and unspecified empyema declined after PCV13 introduction.

CONCLUSIONS

Although empyema hospitalization rates among U.S. children peaked after PCV7 introduction, rates decreased substantially following the introduction of PCV13.

Pneumococcal infections in elderly patients attending hospital since PCV-13 authorization in Spain

OBJECTIVES

To study the characteristics and outcomes of pneumococcal infections in patients aged ≥65 years since the authorization of the 13-valent pneumococcal conjugate vaccine (PCV-13) in Spain.

METHODS

All pneumococcal pneumonias, empyemas or primary bacteraemias treated at two hospitals in Majorca from 2010 to 2015 were included. Clinical variables, serotypes, and antibiotic susceptibility were collected.

RESULTS

Two hundred and forty-nine pneumonias, 11 primary bacteraemias, and 2 empyemas in 243 patients were studied; 181 (69.1%) men, median age 76 years (range: 66-99). Seven (2.6%) were pneumococcal-vaccinated. Bacteraemia was present in 127 (61.9%) cases and related to a higher severity, p= 0.02, and not having chronic lung disease, p = 0.002. Ninety-seven (37%) episodes involved complications and 30 (11.5%) patients died. Mortality was related with the presence of complications at admission, p < 0.001. Only septic shock was more frequent in patients ≥65 years during the period 2010-2015 compared to the period 2006-2010: 38 of 262 (14.5%) vs. 17 of 212 (8%), p = 0.02. Most infections (57.6%) were due to PCV-13 serotypes but were not related to a worse prognosis. The proportion of PCV-13 serotypes tended to decrease from 61% (non-invasive) and 80% (invasive) in 2010-2011 to 33% and 47% in 2014-2015. The antibiotic susceptibility remained stable.

CONCLUSIONS

Rates of pneumococcal vaccination in elderly patients with pneumococcal infections were very low. Except for septic shock, the main outcome variables (including mortality) were similar to the ones observed in the period preceding PCV-13 authorization. PCV-13 serotypes were responsible for most infections although they showed a decreasing trend.

Bacteremic Pneumonia before and after Withdrawal of 13-Valent Pneumococcal Conjugate Vaccine from a Public Vaccination Program in Spain: A Case-Control Study

OBJECTIVE

To compare the incidence and epidemiology of bacteremic community-acquired pneumonia (CAP) in the setting of changes in 13-valent pneumococcal conjugate vaccine (PCV13) coverage.

STUDY DESIGN

In the region of Madrid, universal immunization with the PCV13 started in May 2010. In July 2012, public funding ceased. Vaccination coverage decreased from >95% to 82% in 2013 and to 67% in 2014. We performed a multicenter surveillance and case-control study from 2009-2014. Cases were hospitalized children with bacteremic CAP. Controls were children selected 1:1 from next-admitted with negative blood cultures and typical, presumed bacterial CAP.

RESULTS

Annual incidence of bacteremic CAP declined from 7.9/100,000 children (95% CI 5.1-11.1) in 2009 to 2.1/100,000 children (95% CI 1.1-4.1) in 2012. In 2014, 2 years after PCV13 was withdrawn from the universal vaccination program, the incidence of bacteremic CAP increased to 5.4/100,000 children (95% CI 3.5-8.4). We enrolled 113 cases and 113 controls. Streptococcus pneumoniae caused most of bloodstream infections (78%). Empyema was associated with bacteremia (P = .003, OR 3.6; 95% CI 1.4-8.9). Simple parapneumonic effusion was not associated with bacteremia. Incomplete PCV immunization was not a risk factor for bacteremic pneumonia.

CONCLUSIONS

High rate of PCV13 immunization was associated with decreased incidence of bacteremic CAP; this incidence increased when rate of immunization fell. Empyema (but not parapneumonic pleural effusion) was associated with bacteremia.

Bacteremia in Early Infancy: Etiology and Management

We reviewed the literature regarding bacteremia in early infancy (age ≤ 90 days). Bacteremia remains a major cause of morbidity and mortality in young infants. However, recent epidemiologic data suggest that the incidence of bacteremia is decreasing and the pathogens responsible for invasive disease are changing. These changes will impact the evaluation and management of young infants. We review the current epidemiology of community-acquired bacteremia in early infancy with particular emphasis on the causative agents, diagnostic evaluation, and empiric and definitive antimicrobial treatment.

Decreased Incidence of Respiratory Infections in Children After Vaccination with Ten-valent Pneumococcal Vaccine

INTRODUCTION

Respiratory tract infections (RTIs) and antibiotic usage are common in children, increasing the risk of antibacterial resistance. The introduction of protein-conjugated pneumococcal vaccines has led to reduction in pneumococcal infections. In 2011, pneumococcal protein-conjugated vaccine-10 was introduced into the national childhood vaccination in Iceland, a population not earlier vaccinated against pneumococcus, with 95% vaccine uptake in the first year. The aim of the study was to evaluate the number of children visiting the Children's Hospital Iceland for RTIs before and after the introduction of the vaccine.

METHODS

Admissions and visits to the Children's Hospital because of RTIs were recorded, and children aged 3 months to 2 years in the nonvaccine eligible cohort (born 2008-2010) were compared with the vaccine eligible cohort (born in 2011). Statistical analysis was done using large sample Z test and incidence rate ratios (IRRs) were calculated.

RESULTS

A significant reduction in incidence rate was found when comparing the nonvaccine eligible cohort with the vaccine eligible cohort, both for acute otitis media (AOM) (IRR: 0.76; 95% confidence interval: 0.67-0.87; P < 0.0001) and for pneumonia (IRR: 0.77; 95% confidence interval: 0.64-0.95; P < 0.01).

CONCLUSION

A significant reduction in hospital visits because of AOM and pneumonia in children vaccinated with pneumococcal protein-conjugated vaccine-10 was established. The abrupt and significant reduction of AOM is unusually clear. This reduction was noted very early after initiation of the vaccination.

Pneumococcal serotype evolution in Western Europe

BACKGROUND

Pneumococcal diseases remain a leading cause of vaccine-preventable death worldwide in children <5 years of age. The seven-valent pneumococcal conjugate vaccine (PCV7) was approved in 2001 in Europe and was introduced into the national immunization programmes of many European countries from 2006-2008. In 2009, higher-valent PCVs (PCV10 and PCV13) became available, replacing PCV7 from 2009-2011. This article describes the evolution of vaccine and non-vaccine serotypes causing invasive pneumococcal disease (IPD) following the introduction of PCVs in Western Europe, based on data from publicly-available medical publications and national surveillance systems from January 2010 to May 2015.

DISCUSSION

In countries with high vaccine uptake, 5-7 years after PCV7 introduction IPD caused by vaccine serotypes has almost disappeared in children. Non-PCV7 serotypes have emerged, particularly serotypes 19A, 7 F, 3 and 1. A rapid and significant reduction of the additional serotypes included in higher-valent vaccines has been observed consistently following the introduction of these vaccines. A significant and rapid decline of serotypes 19A, 7 F, 1 and 6A in both vaccine-eligible and older age groups has been observed in countries using PCV13 while serotype 19A and 3 has increased in countries using PCV10. Serotype 3 has become one of the most prevalent serotypes in adults, with some reduction only in the UK and France. Serotype diversity increased and varied by age group, the type of vaccine in use, and the time since the introduction of higher-valent PCVs. Serotypes that are currently more frequent include 24 F, 22 F, 8 and 15A in countries that use PCV13, and serotypes 19A and 3 in countries that use PCV10. Compared with the time before the introduction of higher valent PCVs, to date, there is no single '19A-like' serotype emerging across countries and most of the newly emerging non-PCV13 vaccine types are less invasive with a low case-carrier ratio.

CONCLUSIONS

It is important to closely monitor not only evolving serotypes but also the magnitude of the effect in order to evaluate the overall impact of pneumococcal vaccination programmes and to initiate the appropriate vaccination strategy. Emerging serotypes may also need to be considered for the future development of new vaccines.

Secular trends (1990-2013) in serotypes and associated non-susceptibility of S. pneumoniae isolates causing invasive disease in the pre-/post-era of pneumococcal conjugate vaccines in Spanish regions without universal paediatric pneumococcal vaccination

This study analyzed temporal trends of non-susceptibility/serotypes in invasive pneumococci from Spanish regions where pneumococcal conjugate vaccines (PCVs) were not included in paediatric immunization programmes. All invasive pneumococcal isolates voluntarily sent to the Spanish Reference Laboratory for Pneumococci (January 1990-December 2013) from hospitals located in target study regions were analyzed by age group. The PCV estimated coverage in children <24 months was correlated with 13-valent PCV (PCV13) serotypes trends. A total of 28,124 invasive isolates were analyzed: 3138 (11.2%) from children <24 months, 2161 (7.7%) from children 24-59 months, 781 (2.8%) from children 5-14 years, and 22,044 (78.4%) from adults. The estimated coverage increased from 17.6% (2002) to around 40% (2010-2013). The percentage of PCV13 serotypes among all isolates over time followed a cubic significant trend (R(2)=0.884), with an increasing trend up to 2001 followed by a decrease (more prominent from 2010 onwards). The estimated PCVs coverage was significantly correlated with the decrease in the percentage of PCV13 isolates in children <24 months (r(2)=0.824) and in adults (r(2)=0.786), mainly due to decreases in serotypes 1 and 7F in adults, and in serogroup 6 and serotypes 7F and 19A in children <24 months. None of the non-PCV13 serotypes stood out with substantial increases in the last period. This study showed that the different serotypes (and its associated non-susceptibility trends) were not equally affected by low PCVs disposition. Lack of impact in certain serotypes as serotype 1 (in children 24-59 months), 6C (in all age groups), and 19A (in adults) suggests the need for increasing vaccine coverage in the target vaccine population to increase direct and indirect protection.

Clinical usefulness of pneumococcal urinary antigen test, stratified by disease severity and serotypes

Early diagnosis of pneumococcal pneumonia facilitates appropriate antibiotic therapy. The urinary antigen test (UAT) is known to be useful for the diagnosis of pneumococcal pneumonia. This study aimed to evaluate the usefulness of UAT in the 13-valent pneumococcal conjugated vaccine (PCV13) era. Community-acquired pneumonia (CAP) cases aged ≥19 years were reviewed retrospectively. This study evaluated the utility of Streptococcus pneumoniae UAT (BinaxNOW^® assay) for diagnosis of pneumococcal CAP, and the relation of the UAT positive rate to age, comorbidities, pneumonia severity, and pneumococcal serotypes. Among 752 microbiologically identified CAP cases, S. pneumoniae (36.7%) was the most common isolate, and of those cases, 56.4% were positive for UAT. UAT positivity varied by pneumococcal serotype (serotype 3, 50%; 9V/9A, 85%; 11A/11E, 54%; 14, 36.4%; 19A, 50%; and 23F, 37.5%), and was significantly increased since 2012, two years after introduction of PCV13. The positive rate of UAT was significantly related to CRP level (P = 0.007) and lobar pneumonia (P = 0.006), but not to age, co-morbidities or prior antibiotic therapy. In conclusion, urinary antigen detection varied depending on the S. pneumoniae serotype. In the PCV13 era, the serotype distribution of pneumococcal pneumonia may be changing, and the clinical usefulness of UAT needs to be monitored. The positive rate of UAT may be influenced by a localized bacterial burden and host reactions.

Evolution of pneumococcal infections in adult patients during a four-year period after vaccination of a pediatric population with 13-valent pneumococcal conjugate vaccine

OBJECTIVES

To describe the distribution of vaccine and non-vaccine pneumococcal serotypes from adult patients for different clinical scenarios, after the introduction of the 13-valent pneumococcal conjugate vaccine (PCV-13) for children.

METHODS

This was a prospective study of pneumococcal infections in adult patients (January 2010 to April 2014) in Hospital Son Llàtzer, Mallorca (Spain). Two different periods of time were compared, the first before (first period) and the second after (second period) the introduction of PCV-13. Information related to clinical characteristics, outcomes of infection, pneumococcal serotypes, and antibiotic susceptibility was collected.

RESULTS

We studied 407 episodes (371 patients), 201 in the first period and 206 in the second period. The majority of patients were male; the median patient age was 68 (range 15-99) years. Infections due to PCV-13 serotypes decreased from 59.7% to 47.6% (p=0.014), mainly serotypes 3, 7, 18C, 19F, and 23F. In the second period, PCV-13 serotypes were the cause of pneumonia in 58.2% of cases and in 40.8% of invasive infections, but these serotypes were not related with any outcome variable. No differences in hospital or intensive care unit admission, severity, or mortality were observed between the two periods. Susceptibility to penicillin (98.2% vs. 95.1%, p=0.03) and amoxicillin (96.5% vs. 91%, p=0.007) was slightly higher in the first period.

CONCLUSIONS

Although a reduction in infections due to vaccine serotypes was observed, close to half of infections in adult patients were caused by PCV-13 serotypes. Even after pediatric vaccination with PCV-13, vaccine serotypes were still responsible for most pneumonia and invasive disease, underscoring the importance of implementing current guidelines and extending vaccination to other risk groups.

Impact of the pneumococcal conjugate vaccines on invasive pneumococcal disease in France, 2001-2012

CONTEXT AND AIMS

Vaccination with the 7-valent pneumococcal conjugate vaccine (PCV7) was recommended in France in 2003 for children <2 years. The 13-valent conjugate vaccine (PCV13) replaced PCV7 in 2010. We assessed the impact of PCVs vaccination on the incidence of invasive pneumococcal diseases (IPD) in French children (0-15 years) and adults (>15 years).

METHODS

IPD rates were calculated using cases reported from 2001 to 2012 to Epibac, a laboratory network. The distribution of serotypes was assessed from invasive isolates serotyped at the National reference Centre for Pneumococci. IPD incidence rates were compared between the pre-PCV7 (2001-2002), late PCV7 (2008-2009) and post PCV13 (2012) periods.

RESULTS

The PCVs coverage increased from 56% in the 2004 birth-cohort to 94% in the 2008 and following birth-cohorts. Following PCV7 introduction, IPD incidence decreased by 19% between 2001-2002 and 2008-2009 in children <2 years, but increased in children aged 2-15 years and adults, despite a sharp decline in PCV7-IPD in all age-groups. After PCV13 introduction, IPD incidence decreased by 34% in children <5 years, by 50% in those aged 5-15 years and 15% in adults from 2008-2009 to 2012. The incidence of PCV13-Non PCV7-IPD decreased by 74% in children <5 years and by 60% in those aged 5-15 years.

CONCLUSIONS

Vaccination with PCV13 was rapidly followed by a decrease in the incidence of all-type IPD in children, in relation with a sharp decrease in the incidence of PCV13-Non PCV7-IPD. Moreover, all-type IPD decreased after PCV13 introduction in older non-vaccinated age-groups, with a shift in the distribution of serotypes. Considering the whole 2001-2012 period, the vaccination with PCV7 and PCV13 resulted in a decline in the incidence of IPD in children up to the age of 5 but not in older children and adults.

Efficacy of 13-valent pneumococcal conjugate vaccine (PCV13) versus that of 7-valent PCV (PCV7) against nasopharyngeal colonization of antibiotic-nonsusceptible Streptococcus pneumoniae

BACKGROUND

Pediatric respiratory infections caused by antibiotic-nonsusceptible Streptococcus pneumoniae (ANSP) continue to present an important challenge, even after introduction of 7-valent pneumococcal conjugate vaccine (PCV7). This randomized double-blind trial assessed the potential additional impact of PCV13 over PCV7 on reducing ANSP carriage.

METHODS

Healthy infants were randomly assigned to receive PCV13 (n = 932) or PCV7 (n = 934) at ages 2, 4, 6, or 12 months. Eight nasopharyngeal specimens were collected by swabbing between ages 2 and 24 months. S. pneumoniae isolates were serotyped and tested for antimicrobial susceptibility by the disk-diffusion method and the Etest. Nasopharyngeal acquisition and prevalence of ANSP during ages 7-24 months were compared between the 2 vaccine groups.

RESULTS

In general, new acquisition of pneumococci nonsusceptible to penicillin, erythromycin, clindamycin, penicillin plus erythromycin, and multiple drugs (≥3 antibiotics) was significantly lower in the PCV13 group compared with the PCV7 group; the main serotypes contributing to this significant decrease were serotype 19F, present in PCV13 and PCV7, and serotypes 6A and 19A, present in PCV13 only.

CONCLUSIONS

PCV13 has a significant added benefit over PCV7 in reducing carriage of ANSP. Because carriage determines transmission, these results suggest that PCV13 will provide protection against ANSP disease that exceeds protection provided by PCV7.

CLINICAL TRIALS REGISTRATION

NCT00508742.

Pneumococcal conjugate vaccine-elicited antibody persistence and immunogenicity and safety of 13-valent pneumococcal conjugate vaccine in children previously vaccinated with 4 doses of either 7-valent or 13-valent pneumococcal conjugate vaccine

BACKGROUND

Pneumococcal conjugate vaccine (PCV) antibody persistence and immunologic memory responses may be indicative of protection in previously vaccinated children. In children vaccinated in a previous study with an infant/toddler regimen of 4 doses of PCV7, 4 doses of PCV13, or 3 doses of PCV7 (infant series) and a dose of PCV13 (toddler dose), this follow-on study evaluated antibody persistence ≥24 months after the toddler dose, and immunogenicity and safety of a follow-on dose of PCV13.

METHODS

Children ≥3 years of age who had completed the initial study received 1 dose of PCV13 in this phase 3, open-label follow-on study in France. Serotype-specific anticapsular immunoglobulin G (IgG) and functional opsonophagocytic activity (OPA) were compared across the previous study vaccination groups, before, 4-7 days (IgG only), and 1 month after follow-on vaccination. Safety was assessed.

RESULTS

Before follow-on vaccination, IgG and OPA levels for the PCV7 serotypes were comparable across vaccination groups, but were generally higher for the 6 additional serotypes in children who received PCV13 in the previous study. At both time points after the follow-on vaccination, IgG and OPA values for all 13 serotypes increased, those for the PCV7 serotypes were similar across vaccination groups, but concentrations for the additional serotypes were higher in children who had received PCV13 in the previous study. PCV13 was well-tolerated.

CONCLUSIONS

Antibody persistence and rapid responses after a follow-on dose of PCV13 suggest that even a single toddler dose of PCV13 is likely to provide protection against the 6 additional PCV13 serotypes.

The incidence of pediatric invasive Haemophilus influenzae and pneumococcal disease in Chiba prefecture, Japan before and after the introduction of conjugate vaccines

The Haemophilus influenzae type b (Hib) vaccine and the heptavalent pneumococcal conjugate vaccine (PCV7) were introduced in Japan in 2008 and 2010, respectively. In 2011, immunization with these two vaccines was encouraged throughout Japan through a governmental program. Children treated in Chiba prefecture for culture-proven invasive H. influenzae disease (IHiD) and invasive Streptococcus pneumoniae disease (IPD) were identified in a prefectural surveillance study from 2008 to 2013. The incidence rate ratio (IRR) and its confidence interval (CI) were calculated to compare the 3 years before and after governmental financial support for vaccination. The average number of IHiD and IPD cases among children <5 years of age in 2011-2013 decreased 84% (IRR: 0.16, 95% CI: 0.09-0.26, p<0.0001) and 51% (IRR: 0.49, 95% CI: 0.37-0.63, p<0.0001) compared with those occurring in 2008-2010. The most common non-PCV7 serotype encountered in 2011 and 2013 was 19A. After governmental subsidization of Hib and PCV7 vaccination, IHiD and IPD decreased in Chiba prefecture, Japan. Continuous surveillance is necessary to determine the effectiveness of these two vaccines and for detection of emerging invasive serotypes.

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

BACKGROUND

The 7-valent pneumococcal conjugated vaccine (PCV7) was introduced to the Israeli national immunization plan (NIP) in July 2009 (administered at age 2, 4 and 12 months), with a fast reduction of invasive pneumococcal disease (IPD) caused by PCV7 serotypes. Starting in November 2010, PCV13 gradually replaced PCV7.

AIM

To report the impact of PCV7/PCV13 sequential introduction on IPD in Israeli children <5 years.

METHODS

An ongoing nationwide, prospective, population-based, active surveillance. All IPD episodes (Streptococcus pneumoniae isolated from blood and/or cerebrospinal fluid) from July 2004 through June 2013 were included.

RESULTS

Overall, 2670 IPD episodes were recorded. Incidence of IPD caused by PCV7+6A serotypes during the PCV13 period vs. pre-PCV period decreased by 95% (Incidence Rate Ratio [IRR]=0.05; 95% CI=0.03-0.09). This reduction was observed in a two-step manner: 90% in the PCV7-period and further 5% in the PCV13-period. The rates of IPD caused by the 5 additional PCV13-serotypes (1, 3, 5, 7F, 19A; 5VT) increased initially by 47%, but subsequently decreased by 79%, resulting in an overall 70% reduction during the entire study period (IRR=0.30; 0.21-0.44). A two-fold increase in non-PCV13 serotypes IPD was observed (IRR=2.43; 1.73-3.66). In total, a 63% reduction of all-serotype IPD episodes was observed in children <5 years (69% and 48% in children <2 and 2-4 years old, respectively).

CONCLUSIONS

After initiation of PCV NIP, a rapid and substantial 2-step IPD reduction was observed in children <5 years. The serotype-specific rate reduction reflected the sequential introduction of PCV7/PCV13.

Decreasing incidence and changes in serotype distribution of invasive pneumococcal disease in persons aged under 18 years since introduction of 10-valent and 13-valent conjugate vaccines in Portugal, July 2008 to June 2012

Binary file ES_Abstracts_Final_ECDC.txt matches

Pneumococcal empyema and complicated pneumonias: global trends in incidence, prevalence, and serotype epidemiology

This review evaluates the serotype epidemiology of complicated pneumococcal pneumonia (CPP) during the period 1990–2012. PubMed and EMBASE were searched using the terms “empyema”, “complicated pneumonia”, “pleural infection”, “necrotizing pneumonia”, “pleural effusion”, “parapneumonic effusion”, “pneumatocele”, or “lung abscess”; “pneumococcal” or “Streptococcus pneumoniae”; and “serotype” for studies on the epidemiology of complicated pneumonias published from January 1, 1990 to October 1, 2013. Studies with data on incidence and serotypes were included; reviews, case reports, and conference abstracts were excluded. Of 152 papers, 84 fitted the inclusion criteria. A few pneumococcal serotypes were predominant causes of CPP, particularly serotypes 1, 19A, 3, 14, and 7F. CPP was a more common manifestation of pneumococcal disease among older (>2 years old) than younger children. The data support increases in both reported incidence rates and proportions of CPP in children and adults during the period 1990–2012; specific increases varied by geographic region. The proportions of serotype 3 and, particularly in Asia, serotype 19A CPP have increased, whereas most studies show declines in serotype 14. Serotype 1 has been a predominant cause of CPP since 1990, while antibiotic resistance was infrequent among serotype 1 isolates. The reported incidence and proportions of CPP among pneumonia cases steadily increased from 1990 to 2012. Several factors might account for these increases, including enhanced disease detection due to a higher index of suspicion, more sophisticated diagnostic assays, and changes in the prevalence of serotypes with capacity to invade the pleural space that were not targeted by the 7-valent pneumococcal conjugate vaccine (PCV7).

Incidence of pediatric invasive pneumococcal disease in the Island of Majorca (2008-2010), an area with non-universal vaccination, and estimations of serotype & children population coverage by available conjugate vaccines

BACKGROUND

The World Health Organization reported in 2007 that inclusion of PCV7 in national immunization programs should be seen as a priority, also encouraging countries to conduct appropriate surveillances for monitoring the impact of vaccination. These analyses should be conducted in specific geographical areas and should be aimed to evolution of invasive pneumococcal disease (IPD), by age groups, clinical presentation, and vaccine serotypes (and non-vaccine serotypes to detect possible replacement). This study aimed to monitor the evolution of IPD incidence in children <15 years requiring hospitalization in the Island of Majorca.

METHODS

A prospective clinical surveillance of all culture and/or PCR-confirmed IPD in children <15 years was performed in all hospitals in the Island of Majorca (approximately 900,000 inhabitants) from January 2008 to December 2010. Incidence rate (IR) was calculated as cases/100,000 inhabitants using children population data.

RESULTS

66 IPDs were identified: 39 (59.1%) parapneumonic pneumococcal empyema (PPE), 16 (24.2%) bacteremic pneumonia (BP), 7 (10.6%) primary bacteremia, 3 (4.5%) meningitis, and 1 (1.5%) osteomyelitis. IRs in the three-year study period were: 64.22 for children 12- < 24 months, 37.21 for those 24-59 months, 22.62 for those <12 months, and 3.98 for children >59 months. By study year, IRs were 21.25 in 2008, 19.89 in 2009 and 9.80 in 2010. The reduction found in 2010 was significant and due to significant reductions in IRs of IPDs caused by serotypes included in PCV10 and PCV13. Overall, estimated serotype coverage by conjugate vaccines was 12.1% for PCV7, 37.9% for PCV10 and 65.2% for PCV13. Of the 66 hospitalized children with IPD, 20 had received at least one dose of PCV7 (13 cases with identified serotype). None of these 13 cases was caused by PCV7 serotypes, all were caused by PCV13 serotypes and only 53.8% by PCV10 serotypes.

CONCLUSIONS

The results of the present study evidence the importance of expanding the number of serotypes covered by PCV, and the added value of PCV13 with respect to PCV10 and PCV7, even in an area of low prevalence of 19A as the Island of Majorca.

Towards the 13-valent pneumococcal conjugate universal vaccination: effectiveness in the transition era between PCV7 and PCV13 in Italy, 2010-2013

Pneumococcal disease epidemiology has changed after introduction of pneumococcal conjugate vaccines. Seven-valent vaccine (PCV7) has been effective in reducing invasive pneumococcal disease (IPD). In Europe, PCV13 effectiveness was estimated at 78% (95% CI: -18-96%) for 2-priming doses. In Italy, PCV7 was introduced in 2006 in the childhood immunization schedule and replaced with PCV13 in 2010. In Apulia, vaccination coverage has reached 95.1% (birth-cohort 2010). We estimated PCV program effectiveness and its impact on S. pneumoniae diseases. PCV EFFECTIVENESS: We used the screening method. We calculated the Proportion of Population Vaccinated from immunization registries and detected cases through a laboratory-confirmed surveillance among hospitalized children≤60 months. A confirmed IPD case was a child with PCR positive for S. pneumoniae. Differences among children were assessed with the Chi-square or the Fisher exact test (P value<0.05). PCV IMPACT: We constructed time series using outcome-specific Poisson regression models: hospitalization rate in pre-PCV era and hospitalization risk ratios (RRs) with 95% CIs for both PCV7 and PCV7/PCV13 shifting era. We calculated hospitalization RR with 95% CIs comparing pre-PCV years with vaccination period. The PCV effectiveness was 84.3% (95% CI: 84.0-84.6%). In May 2010-January 2013, we enrolled 159 suspected IPD of whom 4 were confirmed. Two (fully vaccinated) were caused by serotype 9V, 1 (not vaccinated) by serotype 3, 1 (vaccinated with 2 PCV13 doses) by 15B/C. The most important reduction was for pneumococcal pneumonia (RR: 0.43, 95% CI: 0.21-0.90). The PCV program show promising results in terms of both PCV13 effectiveness and its impact in reducing IPD in children<5 years.

The majority of adult pneumococcal invasive infections in Portugal are still potentially vaccine preventable in spite of significant declines of serotypes 1 and 5

In Portugal, pneumococcal conjugate vaccines have been administered to children outside of the national immunization plan since 2001. We determined the serotype and antimicrobial susceptibility of 1265 isolates responsible for adult invasive pneumococcal infections (IPD) between 2009 and 2011 and compared the results with previously published data from 1999 to 2008. Serotypes 3 (12.6%), 7F (10.0%), 19A (9.1%), 14 (8.4%), 1 (6.9%) and 8 (6.2%) were the most frequent and together accounted for 53.2% of adult IPD. Serotypes 1 and 5 declined significantly while serotype 34, not included in any vaccine, increased. Taken together, the serotypes included in the 13-valent conjugate vaccine (PCV13) peaked among adult IPD isolates in 2008 (70.2%) and declined since then reaching 53.5% in 2011. The decline in the serotypes included in the 23-valent polysaccharide vaccine since 2007 was also significant but much more modest with 79.2% of the isolates causing IPD in 2011 expressing these serotypes. Since the changes in serotypes causing IPD in adults coincided with the 10-valent and PCV13 introduction in children, it is unlikely that vaccination triggered these changes although it may have accelerated them. The proportion of IPD caused by serotypes included in the 7-valent conjugate vaccine remained stable (19.0%). Both penicillin non-susceptibility and erythromycin resistance increased in the study period, with serotypes 14 and 19A accounting for the majority of resistant isolates.

Immune response to 13-valent pneumococcal conjugate vaccine with a reduced dosing schedule

BACKGROUND

The 7-valent pneumococcal conjugate vaccine (PCV7) has demonstrated effectiveness against pneumococcal illnesses when administered as 3 infant doses plus a toddler dose (3+1 schedule) or as an abbreviated schedule of 2 infant doses plus a toddler dose (2+1 schedule). The 13-valent pneumococcal conjugate vaccine (PCV13) is approved and World Health Organization-prequalified for administration in a 2+1 schedule when used as part of routine immunization programs.

OBJECTIVE

To summarize immunologic responses elicited by PCV13 administered in a 2+1 schedule and following 2 doses in a 3+1 schedule.

METHODS

Studies were double-blind, randomized, active-controlled, multicenter studies except the Mexico study (open-label, single-arm). In 2+1 studies, PCV13 was administered at 2, 4, and 12 (UK) or 3, 5, and 11 (Italy) months. In 3+1 studies (Spain and Mexico), assessment was made postdose 2 of the primary series (2, 4, and 6 months). The primary immunogenicity endpoint was the proportion of participants achieving serotype-specific antipolysaccharide immunoglobulin (Ig)G concentrations ≥ 0.35μg/mL (i.e., responders) 1 month postdose 2. Pneumococcal IgG geometric mean concentrations (GMCs), opsonophagocytic activity (OPA), and concomitant vaccine responses were assessed.

RESULTS

PCV13 and PCV7 elicited comparable immune responses for the 7 common serotypes after 2 infant doses. The proportion of PCV13 responders postdose 2 was >85% for most of the 7 common and 6 additional serotypes, except common serotypes 6B (27.9-81.4%) and 23F (55.8-77.5%) and additional serotypes 3 (73.8-96.9%) and 6A (79.2-94.4%). Serotypes 6B and 23F elicited lower IgG GMCs postdose 2 compared with other serotypes; all serotypes demonstrated boosting posttoddler dose. All serotypes demonstrated functional activity; >95% of participants achieved OPA levels ≥ 1:8 postdose 2. Concomitant vaccine responses were similar between PCV13 and PCV7 groups.

CONCLUSION

Immune responses elicited by PCV13 following 2 infant doses support transition from PCV7 to PCV13 in countries using a 2+1 schedule.

Expansion of serotype coverage in the universal pediatric vaccination calendar: short-term effects on age- and serotype-dependent incidence of invasive pneumococcal clinical presentations in Madrid, Spain

In Madrid, Spain, the 13-valent pneumococcal conjugate vaccine (PCV13) replaced PCV7 in the pediatric universal vaccination calendar in June 2010. A prospective clinical surveillance that included all children hospitalized with culture- and/or PCR-confirmed invasive pneumococcal disease (IPD) was performed in all Madrid hospitals. The incidence rates (IRs) (defined as the number of cases/100,000 inhabitants aged <15 years) in the PCV7 (May 2007 to April 2010) versus PCV13 (May 2011 to April 2012) periods were compared. There were 499 cases in the PCV7 period and 79 cases in the PCV13 period. Globally, the IR significantly decreased from 17.09 (PCV7 period) to 7.70 (PCV13 period), with significant decreases (PCV7 versus PCV13 periods) in all age groups for bacteremic pneumonia (5.51 versus 1.56), parapneumonic pneumococcal empyema (PPE) (5.72 versus 3.12), and meningitis (2.16 versus 0.97). In the PCV13 period, significant reductions (the IR in the PCV7 period versus the IR in the PCV13 period) were found in IPDs caused by PCV13 serotypes (13.49 versus 4.38), and specifically by serotypes 1 (globally [4.79 versus 2.53], for bacteremic pneumonia [2.23 versus 0.97], and for PPE [2.26 versus 1.17]), serotype 5 (globally [1.88 versus 0.00], for bacteremic pneumonia [0.89 versus 0.00], and for PPE [0.55 versus 0.00]), and serotype 19A (globally [3.77 versus 0.49], for bacteremic pneumonia [0.72 versus 0.00], for PPE [0.89 versus 0.00], and for meningitis [0.62 versus 0.00]). IPDs caused by non-PCV13 serotypes did not increase (IR, 3.60 in the PCV7 period versus 3.31 in the PCV13 period), regardless of age or presentation. No IPDs caused by the PCV13 serotypes were found in children who received 3 doses of PCV13. The number of hospitalization days and sanitary costs were significantly lower in the PCV13 period. The switch from PCV7 to PCV13 in the universal pediatric vaccination calendar provided sanitary and economical benefits without a replacement by non-PCV13 serotypes.