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Comparing COVID-19 vaccine effectiveness in Türkiye: heterologous, inactivated, and mRNA vaccines
Alpay Ari1, Zeynep Altinay2, Didem Demircan1
1Izmir Provincial Directorate of Health, University of Health Sciences Izmir Bozyaka Education and Research Hospital, Izmir, Türkiye.
Insights
mRNA and heterologous vaccines offered the most durable protection against severe COVID-19. Inactivated vaccines also reduced severe outcomes in older adults, highlighting their role in public health strategies.
Area of Science:
- Immunology
- Vaccinology
- Public Health
Background:
- Investigating COVID-19 vaccine effectiveness in Türkiye.
- Comparing heterologous, inactivated, and mRNA vaccine responses.
- Assessing prevention of hospitalization, ICU admission, and mortality.
Purpose of the Study:
- To evaluate the real-world effectiveness of various COVID-19 vaccine types.
- To compare the durability and protective capacity of different vaccine platforms.
- To inform public health policy regarding vaccine deployment.
Main Methods:
- Analysis of PCR-confirmed COVID-19 cases (n=24,538) aged ≥ 18 years.
- Survival distribution analysis across six vaccine types.
- Stratified analysis for individuals < 65 and ≥ 65 years.
Main Results:
- Two-dose mRNA and heterologous vaccines demonstrated superior protective and durable effectiveness.
- Homologous and heterologous inactivated vaccines significantly reduced severe COVID-19 in individuals > 65 years.
- Distinct severe disease outcome patterns were observed based on age and vaccine type.
Conclusions:
- Early use of inactivated vaccines provided timely protection, mitigating severe outcomes.
- mRNA and heterologous vaccines offer robust and lasting defense against severe COVID-19.
- Findings are crucial for optimizing vaccine strategies in diverse healthcare settings.
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.
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