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

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.

Methods: This was a population-based cohort study involving 1 108 634 women and 951 011 men aged ≥50 years in Catalonia, Spain. Baseline characteristics of cohort members were established according to Institutional Research Database and pneumococcal disease-related hospitalizations (PDRH) captured from hospital discharge codes from 68 reference Catalonian hospitals during 2017-2018. Cox regression models were used to estimate PPsV23/PCV13 effectiveness against PDRH by sex.

Results: Across the 2-year follow-up, 4302 PDRH cases (1878 women, 2424 men) were observed, with incidences of 169.4/100 000 and 254.9/100 000 for women and men, respectively. Among women, neither PPsV23 (hazard ratio [HR], 1.04; 95% confidence interval [CI], .92-1.18; P = .540) or PCV13 (HR, 1.24; 95% CI, .91-1.70; P = .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 = .021) whereas PPsV23 did not significantly alter this risk (HR, 0.89; 95% CI, .72-1.10; P = .275). No reduced risk of death following PDRH was observed in vaccinated women or men. However, regarding all-cause death, PPsV23 showed slight reduction in risk for women (HR, 0.94; 95% CI, .92-.97; P < .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.