Monitoring the Establishment of VOC Gamma in Minas Gerais, Brazil: A Retrospective Epidemiological and Genomic Surveillance Study

Abstract

Since its first identification in Brazil, the variant of concern (VOC) Gamma has been associated with increased infection and transmission rates, hospitalizations, and deaths. Minas Gerais (MG), the second-largest populated Brazilian state with more than 20 million inhabitants, observed a peak of cases and deaths in March–April 2021. We conducted a surveillance study in 1240 COVID-19-positive samples from 305 municipalities distributed across MG’s 28 Regional Health Units (RHU) between 1 March to 27 April 2021. The most common variant was the VOC Gamma (71.2%), followed by the variant of interest (VOI) zeta (12.4%) and VOC alpha (9.6%). Although the predominance of Gamma was found in most of the RHUs, clusters of Zeta and Alpha variants were observed. One Alpha-clustered RHU has a history of high human mobility from countries with Alpha predominance. Other less frequent lineages, such as P.4, P.5, and P.7, were also identified. With our genomic characterization approach, we estimated the introduction of Gamma on 7 January 2021, at RHU Belo Horizonte. Differences in mortality between the Zeta, Gamma and Alpha variants were not observed. We reinforce the importance of vaccination programs to prevent severe cases and deaths during transmission peaks.

Association between SARS-CoV-2 Viral Load and Patient Symptoms and Clinical Outcomes Using Droplet Digital PCR

“…Determining the utility of an accurately determined SARS-CoV-2 viral load in optimizing early treatment eligibility, preventing transmission by identifying asymptomatic carriers and infectiousness after the disease, and determining the prognosis remain open questions [ 1 , 2 , 3 ]. Studies have evaluated the correlations between the viral load and the transmissibility, vaccination status, age, comorbidities, and disease severity [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. These studies, however, have generated conflicting results.…”

Can SARS‐CoV‐2 screening in oral biopsies aid epidemiological surveillance?

“…Phylogenetic reconstruction revealed that all three samples were assigned as Alpha (B.1.1.7) variant and first detected in Brazil in December 2020. The VOC Alpha variant expanded its dissemination rate between January and February 2021, starting to decrease in March when the VOC Gamma (P.1) incidence exploded around the country 24,25 . All three sequenced samples were collected during the first 10 days of February 2021.…”

“…Therefore, COVID-19 asymptomatic monitoring must continue based on RT-qPCR analysis of nasopharyngeal swabs and saliva samples.Although insufficient for epidemiological surveillance, the whole viral genome sequencing brought interesting results to our study.Phylogenetic reconstruction revealed that all three samples were assigned as Alpha (B.1.1.7) variant and first detected in Brazil in December 2020. The VOC Alpha variant expanded its dissemination rate between January and February 2021, starting to decrease in March when the VOC Gamma (P.1) incidence exploded around the country 24,25. All three sequenced samples were collected during the first 10 days of February 2021.…”