P107 - Vaccine effectiveness against SARS-CoV-2 infection in Romanian healthcare workers: A prospective cohort study

INTRODUCTION: SARS-CoV-2 causes a wide spectrum of clinical manifestations with different severities in humans, ranging from asymptomatic to life-threatening critical cases. Romania officially declared its first case of COVID-19 on February 26, 2020. The emergency use authorization for COVID-19 vaccines brought both hopes to healthcare workers at the frontline against the COVID-19 pandemic. Vaccine effectiveness against COVID-19 has been measured in the sanitized environment of clinical trials; however, determining these vaccines' real-world impact is still under research. METHODS: We aimed to evaluate the effectiveness of one, two, and three vaccine doses against SARS-CoV-2 infection in healthcare workers in Cluj-Napoca, Romania. A prospective cohort study was conducted among all healthcare workers at the infectious disease hospital in Cluj-Napoca from December 26, 2020, to March 31, 2022. We examined the uptake of any COVID-19 vaccine as the primary outcome and its effectiveness against the apparition of SARS-CoV-2 symptoms with positive Polymerase Chain Reaction (PCR). RESULTS: During the 16 months of the follow-up study, the SARS-CoV-2 infection was confirmed in 27.2% of healthcare workers. In total, the mean age was 44.9, ranging from 20 to 69. A female predominance of 81.9% had been observed. Overall, 61.7% of HCWs worked in the clinical unit. 81.4% had no previous infection with SARS-CoV-2 before vaccination. The source of infection was unknown to the majority (57.5%). At the time of PCR testing, those vaccinated with two doses were the most common (39.3%), followed by those vaccinated with three doses (32.8%), and those unvaccinated (27.3%). CONCLUSION: This work's results provide answers to questions about the effectiveness of COVID-19 vaccines in real-world conditions which is still being debated in several studies, particularly since the appearance of various COVID-19 variants. MOTS CLÉS: COVID-19 , HCWs , Vaccine , Effectiveness , Pandemic DÉCLARATION DE LIENS D'INTÉRÊTS: Les auteurs n'ont pas précisé leurs éventuels liens d'intérêts.