Systematic review on the impact of the pneumococcal conjugate vaccine ten valent (PCV10) or thirteen valent (PCV13) on all-cause, radiologically confirmed and severe pneumonia hospitalisation rates and pneumonia mortality in children 0-9 years old

Streptococcus pneumoniae serotype distribution in low- and middle-income countries of South Asia: Do we need to revisit the pneumococcal vaccine strategy?

S. pneumoniae serotypes responsible for pneumococcal disease differ with respect to disease severity, invasiveness, antimicrobial susceptibility, geographies, immunization history, age groups, and with time. Although PCVs have blunted the pneumococcal disease burden, they are plagued with numerous challenges, especially the emergence of NVTs. In this review, we show that there are diverse serotypes, especially NVTs, responsible for causing pneumococcal diseases in LMICs of South Asia across different studies conducted between 2012 and 2024. We propose that pharmaceutical/biotech companies should tailor/customize the PCVs as per the region-specific serotype prevalence based on surveillance data. Furthermore, protein-based vaccines, or WCVs, have been explored and can serve as viable alternatives to address the limitations associated with PCVs. However, robust studies are warranted in different geographies to demonstrate its efficacy and safety in clinical trials as well as the real-world effectiveness of these promising candidates.

Effectiveness of pneumococcal conjugate 13-valent vaccine against severe pneumonia in Panama: a matched case-control study

OBJECTIVE

In Panama, the 13-valent pneumococcal conjugate vaccine (PCV13) was included in the primary immunization schedule in 2010 with a 3-dose schedule. The authors evaluated the effectiveness of PCV13 against severe community-acquired pneumonia in children of Panama after its introduction into the national immunization program.

METHODS

A retrospective matched case-control study was conducted at Hospital del Niño Doctor José Renán Esquivel, collecting data from children 2 to 59 months of age in years subsequent to the introduction of the PCV13 vaccine (2013-2015). Cases of severe community-acquired pneumonia had radiographically confirmed pneumonia (consolidated or with pleural effusion) or pneumonia with "other infiltrate" associated with CRP ≥ 40 mg/L with severity criteria according to the 2013 World Health Organization definition. Controls were children hospitalized for non-immune-preventable diseases matched by cases' age and admission date. Vaccine effectiveness was estimated as (1 - odds ratio) × 100 % with 95 % confidence intervals.

RESULTS

78 paired cases with 198 controls were included. In the cases, the mean age was 13.7 ± 10.3 SD months, and the hospital stay was 9.7 + 6.1 days. Overall, the effectiveness of PCV13 against severe community-acquired pneumonia was 54.0 % (95 % CI 25.0-72.0 %, p < 0.05). Vaccine effectiveness among children under 1 year was 61 % (95 % CI: 23.0-81.0 %) and 43 % (95 % CI:16.0-74.0 %) for children 1 to 4 years. For children who received at least 1 PCV13 dose was 17.2 % (95 % CI: 8.8-33.7 %). Overcrowding and lack of vaccination against influenza were risk factors for lower vaccine effectiveness.

CONCLUSIONS

PCV13 was effective in preventing severe cases of community-acquired pneumonia in children in Panama.

The enigmatic voyage of pneumococcal carriage: Unraveling the risk factors in pediatric populations -- A scoping review

BACKGROUND

Pneumococcal infections are a major cause of morbidity and mortality globally, especially among children in low- and middle-income countries (LMICs). Although considerable research has been done on the frequency of pneumococcal infections and their risk factors, there are still many unanswered questions. The objective of this study is to offer fresh perspectives through systematic literature review on the shifting prevalence of and associated risk factors for pneumococcal colonization.

METHODS

A systematic search of literature from January 2012 to December 2023 was conducted using PubMed and Scopus, with keywords related to Streptococcus pneumoniae colonization and risk factors, and references were manually screened.

RESULTS

Studies from 41 different countries are included in the evaluation, which focuses on pediatrics patients who are most vulnerable to pneumococcal infections. The most frequent risk variables for pneumococcal colonization were having siblings, daycare centers, passive smoking, household characteristics, age, comorbidities, and vaccination status. The frequency of pneumococcal colonization was greatest among LMICs, which may be related to inadequate pneumococcal vaccination programs, densely populated areas, and a lack of knowledge about basic sanitation and hygiene.

CONCLUSION

The study emphasizes how crucial it is to monitor serotype prevalence to direct vaccination campaigns in these regions. For creating efficient pneumococcal disease prevention and control strategies, it is essential to understand the risk factors connected to pneumococcal colonization. The review highlights the value of vaccination campaigns in lowering the prevalence of pneumococcal illness, to completely understand the relationship between immunization, serotype colonization, and the risk of pneumococcal colonization, more study is required especially in LIC and LMIC region.

Parental experience with childhood COVID-19 vaccines and factors associated with parental hesitancy despite being vaccinated: findings of a cross-sectional analysis from Pakistan and implications for the future

OBJECTIVES

This study examined parental experiences with COVID-19 vaccination and factors contributing to COVID-19 vaccine hesitancy (CVH) among them to help guide future policy initiatives.

DESIGN

Cross-sectional study.

SETTING

Lahore, the second largest metropolis in Pakistan.

PARTICIPANTS

This study was conducted among parents residing in Lahore from March to April 2023. Participants were recruited via convenience sampling.

OUTCOME MEASURES

Data were collected using a prevalidated questionnaire that consisted of four sections: (1) informed consent, (2) demographic details, (3) COVID-19 vaccine uptake in children aged 5-17 years, parents' experience with childhood COVID-19 vaccination and their intention to vaccinate their unvaccinated children and (4) a modified 5C scale tailored to determine parents' confidence, complacency, constraints, calculation and collective responsibility with regard to COVID-19 vaccination.

RESULTS

This study included 414 parents (median age=37 years; mothers=62%). COVID-19 vaccination rates for children in the age groups 12-17 years and 5-11 years were 72.5% and 30.1%, respectively. Transient adverse events following immunisation were reported by 32.7% of parents. Of parents with unvaccinated children aged 12-17 years, only 35% intended to vaccinate them. The majority of parents were not willing to vaccinate their children below 11 years of age. Parents with a self-reported positive history of COVID-19 disease (OR=2.531, p=0.016), and confident in the vaccine's safety and efficacy (OR=1.968, p=0.010), were more inclined to vaccinate their 5-11 years. In terms of vaccination of children below 5 years, confidence in the vaccine (OR=2.942, p=0.003) and a sense of collective responsibility were positive predictors (OR=2.260, p=0.035), while calculation was identified as a negative predictor of parents' intention to vaccinate their under 5 years (OR=0.421, p=0.018).

CONCLUSION

CVH was significantly higher among parents of children aged 5-11 years and children younger than 5 years old. Priority should be given by health authorities to address parental concerns about vaccines and ensure that parents understand the significance of vaccination in protecting their children, to increase vaccination rates. This is because hesitancy towards one specific vaccine can negatively impact hesitancy rates in general.

Pediatric invasive pneumococcal disease in Bolívar, Colombia: a descriptive cross-sectional study

Introduction

Invasive pneumococcal disease (IPD) remains a pediatric health challenge despite national vaccination efforts in Colombia. We described the socio-demographic, epidemiological, and clinical characteristics of children (<18 years of age) with IPD at a pediatric reference center in Bolívar, Colombia.

Methods

Descriptive cross-sectional study of all pediatric patients (under 18 years of age) diagnosed with IPD between 2016 and 2023. Data was collected retrospectively from medical records. IPD was defined as identifying Streptococcus pneumoniae (Spn) in blood, cerebrospinal, pleural, synovial, peritoneal, or pericardial fluid. Spn serotyping data was provided by the Colombian National Institute of Health. Descriptive statistics were performed to describe all variables.

Results

Between 2016-2023, we identified fifty-four pediatric IPD cases. Most cases were reported among children in the 2-9 age group (44.4%), male sex (57.4%), low socio-economic strata (100%), and previous medical conditions (61.1%). Half of the patients were vaccinated. Serotyping data were available from 35 (64.8%) isolates. Fifteen Spn serotypes were identified, Spn19A being the most frequent (20.4%). All Spn isolates were vancomycin sensitive, while 34% had meropenem-decreased sensitivity. Three-quarters of the patients (76.0%) were diagnosed with bacteremia (bacteremic pneumonia/meningitis and bacteremia without known focus). The 79.6% of children were admitted to the pediatric intensive care unit (PICU). The median hospitalization days were 13.5 (IQR 5.5-23.5) while the median PICU length of stay was 9.5 (IQR 4-18) days. Nineteen patients died (35.2%).

Conclusion

IPD disproportionately affects vulnerable children, resulting in high PICU admission and mortality rates and prolonged hospital stay in Bolívar, Colombia. In addition, the emergence of resistance to carbapenems is of concern.

Fractional Doses of Pneumococcal Conjugate Vaccine - A Noninferiority Trial

BACKGROUND

Pneumococcal conjugate vaccines are an expensive component of the routine immunization schedule. Fractional-dose regimens may be one option to increase the sustainability of the vaccine program.

METHODS

We assessed whether the immunogenicity of fractional doses of the 10-valent and 13-valent pneumococcal conjugate vaccines (PCV10 [GSK] and PCV13 [Pfizer], respectively) would be noninferior to that of the full doses and analyzed the prevalence of vaccine-serotype carriage. We randomly assigned healthy infants in Kenya to one of seven equal-sized trial groups. Participants in groups A through F were assigned to receive either a fractional or full dose of PCV10 or PCV13, administered as two primary doses plus one booster dose. In group A, participants received a full dose of PCV13; group B, a 40% dose of PCV13; group C, a 20% dose of PCV13; group D, a full dose of PCV10; group E, a 40% dose of PCV10; and group F, a 20% dose of PCV10. Participants in the seventh group (group G) received a full dose of PCV10 as three primary doses without a booster. Immunogenicity was assessed 4 weeks after the primary series of doses and 4 weeks after the booster dose. Noninferiority could be declared 4 weeks after the primary series if the difference in the percentage of participants with a threshold response was not more than 10% and 4 weeks after administration of the booster if the ratio of the geometric mean concentration (GMC) of IgG was more than 0.5. A vaccine dose was prespecified as noninferior if it met the noninferiority criterion for at least 8 of the 10 vaccine types in the PCV10 groups or at least 10 of the 13 vaccine types in the PCV13 groups. Carriage was assessed when participants were 9 months and 18 months of age.

RESULTS

In the per-protocol analysis, 40% of a full dose of PCV13 met the noninferiority criterion for 12 of 13 serotypes after the primary series and for 13 of 13 serotypes after the booster. The immunogenicity of the 20% dose of PCV13 and of the 40% and 20% doses of PCV10 was not noninferior to that of the full doses. The prevalence of vaccine-serotype carriage was similar across the PCV13 groups at 9 months and 18 months of age.

CONCLUSIONS

In a three-dose schedule (two primary doses and a booster), 40% doses of PCV13 were noninferior to full doses for all included serotypes. Lower doses of PCV13 and PCV10 did not meet the criteria for noninferiority. (Funded by the Bill and Melinda Gates Foundation and others; ClinicalTrials.gov number, NCT03489018; Pan African Clinical Trial Registry number, PACTR202104717648755.).

Incidence of pneumococcal disease in children in Germany, 2014-2019: a retrospective cohort study

BACKGROUND

Novel, expanded valency pneumococcal conjugate vaccines (PCVs) are in development to reduce the burden of pneumococcal disease (PD) in children. To understand the potential value of new vaccines in Germany, this study estimated the residual burden of PD in children < 16 years old from 2014 to 2019, using administrative health data from a large German claims database.

METHODS

Outpatient and inpatient cases of all-cause pneumonia (ACP), pneumococcal pneumonia (PP) and invasive pneumococcal disease (IPD) were identified in the InGef database. Incidence rates (IRs) with 95% confidence intervals (CI) were calculated as number of episodes/person-years (PY) at risk. The Mann-Kendall test assessed time trends in incidence.

RESULTS

There were no significant trends in IRs of IPD or PP from 2014 to 2019. For ACP, IRs declined from 2014 to 2019; 2,213 (CI 2,176-2,250) to 1,503 (CI 1,472-1,534) per 100,000 PY (p = 0.017). IRs of ACP and PP were highest among children aged 12-23 months; 4,672 (CI 4,584-4,762) and 20.8 (CI 15.3-27.5) per 100,000 PY, respectively. For IPD, children 5-11 months-old had the highest IRs, at 14.7 (CI 9.0-22.7) per 100,000 PY.

CONCLUSIONS

From 2014 to 2019 there were no discernible trends in the IRs of PP or IPD, but the IRs of ACP declined in children aged < 16 years. The highest IRs of ACP, PP and IPD were observed in children < 2 years of age, highlighting the importance of infant pneumococcal vaccination in the prevention of pediatric PD. The clinical burden of pediatric PD in Germany persists. Continued surveillance of changing pneumococcal burden, serotype distribution, antimicrobial resistance and vaccination status is critical to better understand the factors driving incidence of PD and to inform future vaccination strategies.

Burden of Pneumococcal Disease in Young Children Due to Serotypes Contained in Different Pneumococcal Conjugate Vaccines in Eight Asian Countries and Territories

BACKGROUND

Pneumococcal disease (PD) is a major cause of morbidity and mortality in young children in Asia and globally. Pneumococcal conjugate vaccines (PCVs) have significantly reduced the burden of PD when included in pediatric national immunization programs (NIPs). This study estimates the clinical and economic burden of PD due to serotypes contained in different PCVs in children aged < 5 years in eight Asian countries/territories.

METHODS

Based on published data, a cohort-based decision analytic model was used to estimate annual PD cases, deaths, and direct medical costs associated with serotypes contained in PCV10, PCV13, PCV15, and PCV20.

RESULTS

PD incidence rates were lower in regions with PCV13 in their NIP than those without. Serotypes contained in higher but not lower valency PCVs resulted in a significant incremental clinical and economic burden, although the difference between PCV13 and PCV15 serotypes was generally small. Moving from PCV13 to PCV20 was estimated to result in greater clinical and economic burden reductions.

CONCLUSIONS

This study demonstrates the remaining and incremental burden of PD from PCV10 to PCV20 serotypes in young children in selected Asian regions. Extending NIP access to higher-valency PCVs with broader serotype coverage and improving vaccine uptake will help prevent morbidity and deaths and save healthcare costs.

Pneumonia-Related Hospitalizations among the Elderly: A Retrospective Study in Northeast Italy

Background: In both the elderly and children, pneumonia remains one of the leading causes of hospitalization. This study aimed to assess the impact of pneumonia-related hospitalizations in the population over 65 years of age in the Veneto Region. Methods: This retrospective study analyzed hospital discharge records for patients aged 65 and older who resided in the Veneto Region and had a diagnosis of pneumonia from 2007 to 2023. The hospitalizations were identified using specific ICD-9-CM codes for pneumonia as a discharge diagnosis. Hospitalization rates, mortality rates, the prevalence of complications and comorbidities, the length of stay, and associated costs were calculated by age and year. Results: From 2007 to 2023, there were 139,201 hospitalizations for pneumonia. Emergency admissions accounted for 92.1% of these cases, and only 2.0% had a specific diagnosis of pneumococcal pneumonia. The median length of stay was 10 days, and the median diagnosis-related group (DRG) tariff per hospitalization was EUR 3307. Excluding the pandemic years, the hospitalization rates remained stable at approximately 850 cases per 100,000 inhabitants before 2019. After 2022, the rates started to increase again. Overall, in the investigated period, the results showed a negative trend (average Annual Percentage Change (AAPC) of -1.931, p < 0.0001). However, when only considering the pre-pandemic years, the trend was stable, while a decline was observed starting in 2020 (AAPC of -19.697, p = 0.001). The overall discharge mortality rates ranged from 13% to 19.3% but were significantly higher in those over 85 years of age (20.6% compared with 6.5% and 12.0% in the 65-74 and 75-84 age groups, respectively). Conclusions: This study highlights the substantial burden of pneumonia in individuals over 65 years of age, showing the impacts on public health.

Complicated pneumonia caused by group A Streptococcus in children - 2022/2023 infectious season outbreak and update on clinical characteristics

BACKGROUND

An increased incidence of group A Streptococcus (GAS) infections has been observed in pediatric population post-COVID-19 pandemic. While the majority of reports refer to scarlet fever or invasive GAS disease, detailed data on pulmonary manifestations such as complicated community-acquired pneumonia (CAP) are scarce. The aim of this study was to assess the contribution of GAS to complicated CAP in children during the 2022/2023 infectious season.

METHODS

We retrospectively analyzed the etiology and clinical presentation of complicated CAP patients hospitalized in our tertiary care center in Warsaw, Poland, between August 2022 and May 2023.

RESULTS

Among 91 patients with complicated CAP, GAS was the dominant cause constituting 24.2% (22/91; 95% CI 15.8-34.3%) of the study group. 68.2% of GAS pneumonia patients presented symptoms of scarlet fever, and 27.3% had preceding or concurrent viral infection. GAS complicated CAP was associated with longer hospitalization, higher incidence of chest tube insertion, but shorter duration of chest tube drainage than complicated CAP of other etiology. Children with GAS complicated CAP had higher procalcitonin concentration (28.1 vs. 1.5 ng/dL; p<0.0001) and a lower platelets level (254.5 vs. 422 × 103/μL; p = 0.0031) than those with non-GAS infection.

CONCLUSIONS

GAS is currently the predominant pathogen of complicated CAP in children. Clinicians should be aware of the current epidemiological situation and a more severe course of GAS pneumonia in this age group, and should monitor patients presenting with symptoms of scarlet fever and preceding viral infection closely.

Effect of Childhood Pneumococcal Conjugate Vaccination on Invasive Disease Serotypes in Serbia

In Serbia, PCV10 was introduced into the routine immunization for children under 2 in 2018 and replaced by PCV13 in 2022. We evaluated their impact on the distribution of invasive pneumococcal disease (IPD) serotypes across all age groups. Overall, 756 isolates were obtained from patients with IPD between 2010 and 2023 through laboratory surveillance. In the post-vaccination period, serotypes 14, 19F, 23F, and 6A significantly declined, while 3 and 19A considerably increased. This was especially evident in the ≤2 years group, making these serotypes the most prevalent among them. Serotype 3 dominated, representing 19.1% of all invasive isolates prior to 2018 and 33.1% thereafter. While serotype coverage of PCV10 has significantly decreased in the ≤2 years group (from 74.2% before 2018 to 29.5% after 2018), PCV13 coverage was 63.9% after 2018. In the post-PCV period, non-PCV13 serotypes, such as 9N, 10A, 15A, 15B, 15C, 22F, 6C, 6D, and 7C, increased across all isolates. Antibiotic non-susceptibility considerably decreased after 2018. MLST analysis showed shifts in sequence type prevalence, with pre-PCV lineages replaced and ongoing serotype 3 persistence, alongside potential capsule-switching events. These findings emphasize a noticeable shift in the distribution of serotypes and adaptability of pneumococcal populations, highlighting the importance of ongoing surveillance and the requirement for the urgent introduction of higher valent vaccines into the National Immunization Program.

Effect of the PCV 10 vaccination on community-acquired pneumonia hospitalisations after four years of its introduction into the Polish National Immunisation Programme: Follow-up study

BACKGROUND

Vaccination against pneumococci is currently the most effective method of protection against pneumococcal infections. The aim of the study was to analyse changes in hospitalisations and in-hospital deaths due to pneumonia before (2009-2016) and after (2017-2020) the introduction of PCV 10 vaccinations in the National Immunisation Programme in Poland.

METHODS

Data on hospitalisations related to community acquired pneumonia (CAP) in the years 2009-2020 were obtained from the Nationwide General Hospital Morbidity Study. Analyses were made in the age groups: <2, 2-3, 4-5, 6-19, 20-59, 60+ years in 2009-2016 and 2017-2020.

RESULTS

Overall, there were 1,503,105 CAP-related hospitalisations in 2009-2020, 0.7% of which were caused by Streptococcus pneumoniae infections. Children <2 years of age were the most frequently hospitalised for CAP per 100,000 population, followed by patients aged 2-3, 4-5 and 60+ years. In the years 2009-2016, the percentage of CAP hospital admissions increased significantly, and after the year 2017, it decreased significantly in each of the age groups (p<0.001). In the years 2009-2016, a significant increase in hospitalisations for Streptococcus pneumoniae infections was observed in the age groups <2, 2-3 and 4-5 years (p<0.05). A significant reduction in hospitalisations was observed in the age groups <2, 20-59 and 60+ in 2017-2020 (p<0.05). In the years 2009-2020, there were 84,367 in-hospital deaths due to CAP, 423 (0.5%) of which due to Streptococcus pneumoniae, with patients mainly aged 60+.

CONCLUSIONS

Implementation of the PCV vaccination programme has effectively decreased the incidence of CAP hospitalisations, including children <2 years of age. The group that is most at risk of death are persons aged 60+. The results of our study can be useful in evaluating the vaccine efficacy and benefits, and they can be an essential part of public health policy. Effective prevention strategies for CAP should be implemented in different age groups.

Effect of Pneumococcal Conjugate Vaccine on Pneumonia Incidence Rates among Children 2-59 Months of Age, Mongolia, 2015-2021

Starting in June 2016, the 13-valent pneumococcal conjugate vaccine (PCV13) was introduced into the routine immunization program of Mongolia by using a 2+1 dosing schedule, phased by district. We used prospective hospital surveillance to evaluate the vaccine's effect on pneumonia incidence rates among children 2-59 months of age over a 6-year period. Of 17,607 children with pneumonia, overall adjusted incidence rate ratios showed decreased primary endpoint pneumonia, very severe pneumonia, and probable pneumococcal pneumonia until June 2021. Results excluding and including the COVID-19 pandemic period were similar. Pneumonia declined in 3 districts that introduced PCV13 with catch-up campaigns but not in the 1 district that did not. After PCV13 introduction, vaccine-type pneumococcal carriage prevalence decreased by 44% and nonvaccine-type carriage increased by 49%. After PCV13 introduction in Mongolia, the incidence of more specific pneumonia endpoints declined in children 2-59 months of age; additional benefits were conferred by catch-up campaigns.