Effects of COVID-19 and pneumococcal conjugate vaccines on hospitalized older COVID-19 patients in Türkiye.

Background: The COVID-19 vaccine, CoronaVac, and pneumococcal conjugate vaccine, PCV13, are part of Türkiye's adult immunization programme to reduce COVID-19 severity and mortality among older adults.

Aim: To evaluate the effects of CoronaVac and PCV13 vaccines on hospitalized patients aged ≥ 65 years in Türkiye.

Methods: This retrospective descriptive study included 365 patients aged ≥ 65 years admitted to the COVID-19 wards and intensive care unit of Şişli Hamidiye Etfal Training and Research Hospital in Türkiye between March and June 2021. We evaluated vaccine efficacy among patients at ≥ 14 days and < 14 days after the second dose. We analysed the data using SPSS version 20.0 and compared proportions in independent groups using χ² test. P < 0.05 was considered statistically significant.

Results: Intensive care unit admission was lower (25.3%) among patients vaccinated with CoronaVac than among unvaccinated patients (38.5%), and mortality rate was significantly lower (16.9% vs 32.7%) among vaccinated patients. Mortality decreased significantly with the number of vaccine doses. No significant relationship was found between PCV13 vaccination and mortality or intensive care unit admission, but mortality was lower among vaccinated patients.

Conclusion: CoronaVac significantly reduced intensive care unit admissions and mortality among older COVID-19 patients. Although PCV13 did not show a significant reduction in mortality, its observed benefit supports continued pneumococcal vaccination among older populations.