Monitoring the Circulation and Impact of SARS-Cov-2 Variants on Public Health During COVID-19 Pandemic: a Case Study in a South Brazil Population

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was the responsible for the coronavirus disease 2019 (COVID-19) pandemic. Because of its high transmissibility, allied to the emergence of some variants of concern (VOC), like Alpha, Beta, Gamma, Delta, and Omicron, the detection of these strains must be rapid and efficient. Among the tests available, the reverse-transcriptase polymerase-chain reaction (RT-PCR) is considered the gold standard test for COVID-19 detection, and the use of specific primers and probes can discriminate the different COVID-19 variants. In this study, we screened 317 individuals tested positive for COVID-19 from the municipality of Ponta Grossa (Parana State, Brazil), from April/2021 to February/2022, aiming to identify the Gamma, Delta, and Omicron variants, by RT-PCR, using specific probes. The Gamma variant was detected from April/2021 to September/2021. The Delta variant was subsequently detected from August/2021 to November/2021. The Omicron variant was the unique strain detected from December/2021 to February/2022 and, because of its high rate of transmissibility, it caused a considerable increase in the number of COVID-19 infections. Mass testing is considered an important strategy for COVID-19 control and, the correct detection of new strains, could improve the knowledge about the virus ' behavior, permitting the development of drugs and optimized vaccines.