Background: Streptococcus pneumoniae ( Spn ) is a common respiratory pathogen and the main cause of bacterial pneumonia, meningitis, and bacteremia, acute otitis media. Imported 13-valent pneumococcal conjugate vaccine (PCV13) was licensed in China and introduced in Shanghai in 2017.Methods: By calculating propensity scores with logistic regression, a comparison group was formed by frequency matching one unvaccinated child to one vaccinated child. For matching, we used the nearest-neighbor matching algorithm and exact matching, and then created distinct matched analysis sets for two cohorts. A Kaplan-Meier analysis was conducted to measure the cumulative incidence of all-cause pneumonia in both groups and used the log-rank test to assess the differences between the two cumulative incidence curves. Cox proportional hazards regression was used to compare the adjusted hazard ratios (HR) of differences in all-cause pneumonia between the two groups.Results: Completely vaccinated children accounted for 85.7% of the vaccinated children aged. The incidence of pneumonia in the streets and communities of Shanghai’s Songjiang district decreased rapidly from 2017, when PCV13 vaccination presented an overall increasing trend. In unadjusted analyses performed prior to propensity-score matching, PCV13 vaccination was associated with a significantly lower risk of all-cause pneumonia, compared to non-vaccination (prevalence odds ratio, 0.947; 95% CI: 0.985 to 0.996). The estimated vaccine effectiveness against visits for all-cause pneumonia was 19% (95% CI: 3 to 32) after the first dose in children vaccinated with at least one dose of PCV13.Conclusions: PCV13 vaccination among children aged 0-5 years substantially reduced the incidence of all-cause pneumonia. Direct immunization of children under 5 years is an effective strategy to combat outpatient pneumonia, and hospitalized pneumonia.Funding: This work was supported by the Bill & Melinda Gates Foundation, Seattle, WA [grant no. OPP1216424], Shanghai Municipal Science and Technology Major Project [grant no. ZD2021CY001] and Shanghai New Three-year Action Plan for Public Health [grant no. GWV-10.1-XK16].Declaration of Interest: The authors declare that they have no known competing financial interests or personal relationships that could influence the work reported in this paper.Ethical Approval: This study was reviewed and approved by Medical Research Ethics Committee, School of Public Health, Fudan University (International registration number: IRB00002408 & FWA00002399), approval number is IRB# 2019-11-0789. Consent to participate was not applicable.
Streptococcus pneumoniae (Spn) is a common respiratory pathogen and the main cause of bacterial pneumonia, meningitis, and bacteremia, acute otitis media. Imported 13-valent pneumococcal conjugate vaccine (PCV13) was licensed in China and introduced in Shanghai in 2017. We aim to describe PCV13 vaccination trends and pneumonia incidence of children under 5 from 2017 to 2020, then estimate the effectiveness of PCV13 against community-acquired pneumonia (CAP) in children under 5 in Shanghai, China.By calculating propensity scores with logistic regression, a comparison group was formed by frequency matching one unvaccinated child to one vaccinated child. For matching, we used the nearest-neighbor matching algorithm and exact matching, and then created distinct matched analysis sets for two cohorts. A Kaplan-Meier analysis was conducted to measure the cumulative incidence of all-cause pneumonia in both groups and used the log-rank test to assess the differences between the two cumulative incidence curves. Cox proportional hazards regression was used to compare the adjusted hazard ratios (HR) of differences in all-cause pneumonia between the two groups.Children received three or more doses PCV13 accounted for 85.7% of all vaccinated children. The incidence of pneumonia in Shanghai's Songjiang district decreased rapidly from 2017, when PCV13 vaccination presented an overall increasing trend. The estimated vaccine effectiveness against visits for all-cause pneumonia was 19% (95% CI: 3 to 32) after the first dose in children vaccinated with at least one dose of PCV13. The protective effectiveness of PCV13 was found to be higher for hospitalized pneumonia (30%, 95% CI: 5% to 49%) than for outpatient pneumonia (19%, 95% CI: 4% to 32%).PCV13 vaccination among children aged 0-5 years substantially reduced the incidence of all-cause pneumonia. Direct immunization of children under 5 years is an effective strategy to combat outpatient pneumonia, and hospitalized pneumonia.