Evaluating Sex Differences in Pneumococcal Disease Burden and Vaccination Effectiveness in Adults: A Population-Based Study

Abstract

Background: Information concerning sex differences in pneumococcal vaccine effectiveness in adults is scarce. The main aim of this study is to compare the differences in clinical effectiveness of pneumococcal vaccination between male and female adults.

Methods: Population-based cohort study involving 1,108,634 women and 951,011 men aged ≥50years in Catalonia, Spain. Baseline characteristics of cohort members (comorbidities/underlying conditions and PPsV23/PCV13 vaccination status) were established according to Institutional Research Database (SIDIAP) and pneumococcal disease-related hospitalizations (PDRH) captured from hospital discharge codes from 68 reference Catalonian hospitals, throughout 01/01/2017-31/12/2018. Cox regression models were used to estimate PPsV23/PCV13 effectiveness against PDRH by sex (adjusting for age and comorbidities/underlying risk conditions).

Results: Across the two-year follow-up 4,302 PDRH cases (1,878 women, 2,424 men) were observed, with incidences of 169.4/100,000 and 254.9/100,000 for women and men, respectively. Among women, nor PPsV23 ((hazard ratio [HR]:1.04; 95% CI:0.92- 1.18; p=0.540) neither PCV13 (HR:1.24; 95% CI:0.91-1.70; p=0.171)) altered PDRH risk. Among men, PCV13 was associated with significantly increased risk of PDRH (HR: 1.57; 95% CI: 1.07-2.31; p=0.021) whereas PPsV23 did not significantly alter this risk (HR:0.89; 95% CI:0.72-1.10; p=0.275). No reduced risk of death from PDRH was observed in vaccinated women or men. However, regarding all-cause death, PPsV23 showed slight reduction risk for women (HR:0.94; 95% CI:0.92-0.97; p<0.001).

Conclusions: PPsV23/PCV13 vaccinations have not proven effective for either sex in preventing PDRH. PPsV23 appears associated with slight reduction risk of all-cause death in women, which could be related to better or longer-lasting vaccination effects in women compared to men.