Comparison of Delta and Omicron variant of COVID-19 infection cases in Montenegro

Introduction/Objective At the end of 2021, Omicron wave (B.1.1.529) SARS-CoV-2 variant superseded the Delta variant (B.1.617). The main goal of the research is to provide a detailed and comprehensive presentation of data related to people infected with the coronavirus in Montenegro. The specific goal of the research is to determine whether virus mutations influenced the course of the epidemic during its two-year duration.Methods This is a retrospective study. We used data from the Institute of Public Health of Montenegro. Our sample consisted of 127,134 people who tested positive for Delta or Omicron infection aged 0-100 years, who had a positive PCR test for COVID-19 between August 17, 2021 and April 17, 2022.Results The respondents aged 40-49 years were taken as a reference group for age. The results showed that the age group from 20 to 29 years old was affected 1.03 times more than the reference group - persons belonging to the age group of 30-39 years were affected 1.07 times more than the reference group. The Central region was taken as the reference group for the region. The results showed that people who live in southern region got sick 1.14 times more often and people who live in northern region got sick 1.20 times less than people from the central region.Conclusion The biggest predictor that a person would get sick is the age group. Also, the predictor is the region, and in our research, it was southern region.Keywords: COVID-19; SARS-CoV-2; age; Delta and Omicron strain; Montenegro