VACCINE BREAKTHROUGH CASES AMONG HOSPITALISED PATIENTS IN THE INTENSIVE CARE UNIT FOR COVID-19 IN NORTH-EASTERN BULGARIA

Background: COVID-19, caused by SARS-CoV-2, continues to spread globally, with vaccines being the most effective way to control the pandemic. Studies show a significant reduction in infection, hospitalisations, severe disease, and death after vaccination.The aim of the study was to determine the share of breakthrough infections among critically ill patients with severe COVID-19 who had been admitted to the intensive care unit (ICU) of a hospital at the beginning of the delta-variant pick. Material and methods: For a period of 10 months a total of 740 patients diagnosed with COVID-19, were treated in the intensive care unit of the University Hospital “St. Marina-Varna”, with ersons. Information on the vaccination status of all 740 hospitalised patients was extracted from the National information system "Register of immunized persons against COVID-19", including the type and date of COVID-19 vaccine administration, where available. After that, descriptive statistics were performed with the collected data. Results: Out of 740 patients, 19 (2.6%) had received at least 1 dose of vaccine, and 721 (97.4%) - none. Only ten (1.35%) of the studied everely and critically ill patients had completed the vaccination cycle (without a booster dose). Conclusion: Our findings show that when fully administered, vaccines are highly effective against laboratory-confirmed SARS-CoV-2 infection leading to ICU admission. Our findings reinforce the value of widespread COVID-19 vaccination, underscore the importance of completing the vaccination cycle for either of the mRNA-based vaccines, and may help motivate persons who remain hesitant about being vaccinated.