Community-Acquired Pneumonia Incidence in Adults Aged 18 Years and Older in Goto City, Japan

Abstract

Background

Few studies have measured the burden of community-acquired pneumonia (CAP) and pneumococcal vaccine-type CAP in Japan after the introduction of the 23-valent pneumococcal polysaccharide vaccine into the adult national immunization program for individuals aged ≥ 65 years in 2014. In this study, we estimated the incidences of CAP and Streptococcus pneumoniae CAP among Japanese adults between 2015 and 2020.

Research Question

What are the incidences of CAP and S pneumoniae CAP among Japanese adults? What are the common pneumococcal serotypes detected in patients with S pneumoniae CAP?

Study Design and Methods

This prospective population-based multicenter active surveillance study enrolled adults ≥ 18 years of age with clinically and radiologically confirmed CAP in Goto City, Japan. S pneumoniae was detected using standard-of-care blood and sputum cultures, BinaxNOW (Abbott), and serotype-specific urinary antigen detection assays.

Results

A total of 2,103 patients with CAP were enrolled; 84% were aged ≥ 65 years and 6.7% died during the study. The annual CAP, S pneumoniae CAP, 13-valent pneumococcal conjugate vaccine (PCV13) serotype CAP, and 20-valent pneumococcal conjugate vaccine (PCV20) serotype CAP incidences per 100,000 population were 1,280, 227, 63, and 110, respectively. S pneumoniae was detected in 17.8% of all patients with CAP by any detection method, with 4.9%, 5.5%, and 8.6% of cases of CAP resulting from PCV13, 15-valent pneumococcal conjugate vaccine, and PCV20 serotypes, respectively. Applying Goto’s incidence and case fatality rate to the Japanese population, assuming PCV20 has the same vaccine efficacy and duration of protection as PCV13 and if licensed in Japan for the prevention of CAP, the inclusion of PCV20 in the national immunization program for adults ≥ 65 years of age could prevent 29,036 cases of CAP and 2,275 CAP-related deaths per year.

Interpretation

Given the substantial burden of preventable pneumococcal disease, introduction of pneumococcal conjugate vaccines in Japanese adults may be of merit.