VACCINE BREAKTHROUGH INFECTIONS IN COVID-19 PATIENTS - SINGLE CENTER STUDY IN THE REPUBLIC OF NORTH MACEDONIA

Abstract

Our study evaluates vaccine breakthrough infections in Coronavirus Disease 2019 (COVID-19) patients who presented for medical examination at a tertiary care hospital in Skopje, Republic of North Macedonia. We retrospectively evaluated medical files of 249 completely vaccinated patients who presented at the hospital since June 2021 till October 2021, with a clinical picture of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection. The average time from complete vaccination to symptom onset was 79.8±41.8 days. Out of 249 patients, 158(63.45%) were treated as outpatients, and 91(36.55%) were hospitalized. From the hospitalized patients, 61(67.03%) were discharged and 30(32.97) died. Breakthrough infections occurred in the Sinopharm vaccine group in 45.78%, Sinovac in 20.08%, Pfizer in 14.86%, AstraZeneca in 10.84% and Sputnik in 7.23%. The highest mortality was found in patients vaccinated with mRNA1273 vaccine, followed by inactivated virus containing vaccine and with non replicating viral vector vaccine, while the lowest mortality was found in those vaccinated with either BNT162b2 vaccine or human adenovirus vector-based COVID-19 vaccine. Male gender (p=0.006), age over 65 years (p=0.002) and presence of comorbidities (p=0.006) were major contributing factors for a poor outcome in vaccinated hospitalized patients with COVID-19. Due to the uneven distribution of the samples in our patient cohort it would be misleading to look at breakthrough cases, disease severity and outcome by vaccine brand due to different representation of vaccine brands. Breakthrough infection, hospitalization, and death from COVID -19 could differ across different vaccination profiles.