Effect of vaccination and number of doses on disease severity and mortality in Covid -19 positive hospitalized patients

Abstract

The COVID-19 pandemic, caused by the novel SARS-CoV-2 virus, started in December 2019 in the city Wuhan, province Hubei in the Republic of China. The disease quickly became pandemic and infected 48.539.872 people and had a mortality of 1.232.791 in 215 countries all over the world resulting in economic and healthcare collapse. On 11-th of March the World Health Organisation declared COVID 19 as pandemic. SARS-CoV-2 (severe form of acute respiratory syndrome coronavirus 2) as the cause of COVID 19 is the member of the coronavirus family along with MERS-CoV and SARS-CoV-1which cause severe respiratory infections that are highly contagious and have very high mortality. The pandemic character, the high morbidity and mortality and rehabilitation resulted in a massive vaccine production as an attempt to control the spread of the SARS CoV-2 virus and reduce the morbidity and mortality, especially in the most vulnerable population groups. The aim of the study was to evaluate the association between vaccination status, number of doses and disease severity, length of hospital stay and mortality. Material and Methods: In this case-control study we included 230 male and female patients admitted in the Covid Centre in Acibadem Clinical Hospital in Skopje from March 2021 to February 2022. Patients were divided in two groups according to their vaccination status. Data about patients demographics, comorbidities, vaccination, number of doses received, type of oxygen and ventilation support, length of stay and patient outcome were collected. Results: A total of 230 COVID-19 positive hospitalized patients participated in the study. 50.4% of them were vaccinated, of which 86.2% received two doses, 11.2% received one and 2.6% received three doses of vaccines. A significant association was registered between lethal outcome and vaccination (PearsonChi-square: 5.32523, p=.0210), association with number of doses of vaccination (PearsonChi-square: 7.66262, p=.043524), association with type of ventilation - NIV, HFO, IMV (PearsonChi-square: 177.399, df=3, p=0.000), associationwithcomorbidity (3.90770, p=.0480). Conclusion: Vaccination against Covid-19 and number of doses have a significant impact on disease severity, progression and outcome of the disease.