EFFECTIVENESS OF PNEUMOCOCCAL VACCINATION DURING COVID-19 IN RURAL RESIDENTS IN JAPAN
Author(s)
Ayako Shoji, PhD1, Yuriko Hagiwara, BSc, MSc, PhD2, Kenichi Kudo, BS3, Koichi Murashita, M.A.4, Shigeyuki Nakaji, PhD4, Ataru Igarashi, PhD5.
1University of Tokyo, Bunkyo-ku, Japan, 2University of Tokyo, Tokyo, Japan, 3ICI Inc., Tokyo, Japan, 4Hirosaki University, Hirosaki, Japan, 5Faculty of Pharmacy, Tokyo University, Tokyo, Japan.
1University of Tokyo, Bunkyo-ku, Japan, 2University of Tokyo, Tokyo, Japan, 3ICI Inc., Tokyo, Japan, 4Hirosaki University, Hirosaki, Japan, 5Faculty of Pharmacy, Tokyo University, Tokyo, Japan.
OBJECTIVES: The 23-valent pneumococcal polysaccharide vaccine has been recommended for individuals aged ≥ 65 or 60-64 years with high-risk comorbidities in Japan until March 2026. However, its effectiveness in recent years has not been demonstrated due to the COVID-19 epidemic.
METHODS: We utilised individually linked claims data and pneumococcal vaccination records from an area characterised by a high proportion of older residents and low life expectancy. We matched vaccinated residents to unvaccinated residents between 1 January 2018 and 31 March 2023 using risk-set sampling, considering age, sex, Charlson Comorbidity Index (CCI), and residence in care homes. After exact matching, we performed propensity score matching using 1% calipers. We compared the incidence of all-cause pneumonia and hospitalisations associated with pneumococcal diseases (PDs) between the vaccinated and unvaccinated groups. We performed multivariate analyses considering the same matching factors and year of index date to address the increased risk of pneumonia and hospitalisation due to COVID-19.
RESULTS: A total of 10,616 vaccinated individuals were matched to 20,474 unvaccinated individuals. The mean age was approximately 72.5 years, and the mean CCI was approximately 1.8 in both groups. The incidence rate of all-cause pneumonia and hospitalisation following a diagnosis of PDs significantly increased after the COVID-19 epidemic (HR 2681.60, 95% CI 1395.61-5152.57; HR 1797.54, 95% CI 890.38-3628.95). After adjustment, the incidence remained significantly higher in the unvaccinated group compared to the vaccinated group (HR 1.20, 95% CI 1.11-1.30; HR 1.26, 95% CI 1.14-1.37). Male sex, older age, and higher CCI were associated with a higher incidence. The treatment duration for all-cause pneumonia was significantly longer in the unvaccinated group (RR 1.14, 95% CI 1.07-1.21), whereas the duration for hospitalisation following PDs did not differ.
CONCLUSIONS: We observed a low incidence and shorter treatment duration for all-cause pneumonia in the vaccinated population.
METHODS: We utilised individually linked claims data and pneumococcal vaccination records from an area characterised by a high proportion of older residents and low life expectancy. We matched vaccinated residents to unvaccinated residents between 1 January 2018 and 31 March 2023 using risk-set sampling, considering age, sex, Charlson Comorbidity Index (CCI), and residence in care homes. After exact matching, we performed propensity score matching using 1% calipers. We compared the incidence of all-cause pneumonia and hospitalisations associated with pneumococcal diseases (PDs) between the vaccinated and unvaccinated groups. We performed multivariate analyses considering the same matching factors and year of index date to address the increased risk of pneumonia and hospitalisation due to COVID-19.
RESULTS: A total of 10,616 vaccinated individuals were matched to 20,474 unvaccinated individuals. The mean age was approximately 72.5 years, and the mean CCI was approximately 1.8 in both groups. The incidence rate of all-cause pneumonia and hospitalisation following a diagnosis of PDs significantly increased after the COVID-19 epidemic (HR 2681.60, 95% CI 1395.61-5152.57; HR 1797.54, 95% CI 890.38-3628.95). After adjustment, the incidence remained significantly higher in the unvaccinated group compared to the vaccinated group (HR 1.20, 95% CI 1.11-1.30; HR 1.26, 95% CI 1.14-1.37). Male sex, older age, and higher CCI were associated with a higher incidence. The treatment duration for all-cause pneumonia was significantly longer in the unvaccinated group (RR 1.14, 95% CI 1.07-1.21), whereas the duration for hospitalisation following PDs did not differ.
CONCLUSIONS: We observed a low incidence and shorter treatment duration for all-cause pneumonia in the vaccinated population.
Conference/Value in Health Info
2026-11, ISPOR Europe 2026, Vienna, Austria
Value in Health, Volume 29, Issue 12S
Code
EPH203
Topic
Clinical Outcomes, Epidemiology & Public Health, Real World Data & Information Systems
Topic Subcategory
Public Health
Disease
No Additional Disease & Conditions/Specialized Treatment Areas, Vaccines