Comparing COVID-19 vaccine effectiveness in Türkiye: heterologous, inactivated, and mRNA vaccines.

INTRODUCTION

This study investigates the effectiveness of different coronavirus disease (COVID-19) vaccines in preventing hospitalization, ICU admissions, and mortality in Türkiye, upon comparing the responses to heterologous, inactivated, and mRNA vaccines.

METHODOLOGY: Data were gathered from 24,538 individuals, aged ≥ 18 years, whose COVID-19 status was confirmed through PCR testing. An analysis of the survival distributions for six vaccine types showed significant differences in severe disease outcomes, with distinct patterns observed for individuals older and younger than 65 years.

RESULTS

Vaccines, including two-dose mRNA, both heterologous and homologous, showed the most protective and durable vaccine effectiveness. Homologous and heterologous inactivated vaccines demonstrated statistically significant reductions in severe COVID-19 outcomes for individuals aged > 65 years compared to unvaccinated individuals.

CONCLUSIONS

The results suggest that an early deployment of inactivated vaccines, despite being less advanced, may have played an important role in providing timely protection, mitigating severe outcomes, especially in countries with limited access to novel vaccine technologies. This study provides key insights for shaping future vaccine strategies and public health policies, particularly in regions with varying access to healthcare resources.