# Characteristics of health care workers with SARS-CoV-2 at a COVID-19 hospital in Türkiye: Homologous versus heterologous vaccination

## TL;DR

This study examines how different types of vaccination among healthcare workers in Türkiye affected their likelihood of contracting COVID-19.

## Contribution

The study provides insights into the effectiveness of homologous versus heterologous vaccination strategies among healthcare workers in Türkiye.

## Key findings

- Most infected healthcare workers were women and nurses, with very few requiring hospitalization.
- Homologously vaccinated workers contracted COVID-19 later than heterologously vaccinated workers.
- The time between vaccination and infection varied between homologous and heterologous groups.

## Abstract

Given the limited studies on types of vaccination and infection rates among health care workers (HCWs) in Türkiye, we analyzed the demographic, clinical, and vaccination characteristics as well as the attitudes of HCWs who have been infected with COVID-19.

We retrospectively analyzed demographic and clinical data on breakthrough COVID-19 infections in HCWs from hospital surveillance data collected between April 5, 2020, and November 1, 2022. The comparison was based on four subgroups that consisted of unvaccinated, one-shot-vaccinated, homologous vaccinated, and heterologous vaccinated individuals. Participants who received various combinations of Sinovac/CoronaVac and/or BioNTech/Pfizer vaccines were compared for detection of COVID-19.

During a 33-month period of 744 HCWs who contracted COVID-19, women (65.3%) and nurses (28.9%) were the most affected, followed by doctors (25.8%). Of the infected HCWs, only 1.3% required hospitalization, 0.3% required ICU support, and 98.4% were outpatients. By vaccination status, 143 of the HCWs (19.2%) were unvaccinated, 292 (39.2%) were homologously vaccinated, 294 (39.5%) were heterologously vaccinated, 15 (2%) received a single shot, 206 (27.7%) received two shots, and 165 (22.2%) received three shots. All HCWs contracted COVID-19 at a mean of 134-days (range:1-539) after vaccination. While the proportions of homologously and heterologously vaccinated HCWs were similar, the time elapsed from vaccination to contracting COVID-19 varied (mean 143.4±106.7 vs.126.4±82.43 days).

Among both outpatients and inpatients with COVID-19, women HCWs outnumbered men HCWs. HCWs who received homologous vaccination contracted COVID-19 later than those who received heterologous vaccination.