Dispersion of SARS-CoV-2 lineage BA.5.1.25 and its descendants in Peru during two COVID-19 waves in 2022.

During the third year of the pandemic in Peru, the persistent transmission of SARS-CoV-2 led to the appearance of more transmissible and immune-evasive Omicron sublineages; in that context, the National Genomic Surveillance of SARS-CoV-2 performed by the Peruvian National Institute of Health detected spike mutations in the circulating Omicron BA.5.1.25 sublineage which was later designated as DJ.1 and increased during the fourth COVID-19 wave, this eventually branched into new sublineages. The introduction, emergence, and timing of the most recent common ancestor (tMRCA) of BA.5.1.25 and its descendants (DJ.1, DJ.1.1, DJ.1.2, and DJ.1.3) were investigated in this paper as well as the time lags between their emergence and identification by the Peruvian National Institute of Health. Our findings show that ongoing genomic surveillance of SARS-CoV-2 is critical for understanding its phylogenetic evolution and the emergence of novel variations.

Confirmed Severe Acute Respiratory Syndrome Coronavirus 2 Reinfections After a Second Wave With Predominance of Lambda in Lima and Callao, Peru.

Background: Coronavirus disease 2019 (COVID-19) infection is a major public health problem in the world and reinfections are becoming more frequent. Our main objective was to describe the epidemiological, clinical, and genomic characteristics of the confirmed cases of reinfection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the capital of Lima and Callao, Peru. Methods: We searched in the Peruvian laboratory information system from April 2020 up to May 2021, looking for cases having 2 positive molecular tests for SARS-CoV-2 with more than 90 days between them. We performed genomic sequencing to the available pairs of samples and described the clinical characteristics, epidemiological impact, and genomic analysis of the confirmed reinfections. Results: There were 1 694 164 people with a positive diagnostic test for SARS-CoV-2 in Lima/Callao during the study period. Of these, 1695 had 2 positive molecular tests with more than 90 days between them. Two hundred eleven had both samples available for genomic analysis according to our selection criteria, and these were retrieved and submitted to sequencing. Thirty cases were confirmed to be SARS-CoV-2 reinfections with 2 different lineages in the 2 episodes. The variant Lambda (C.37) was the most common during the second infection and accounted for 19 (63.3%) of the 30 cases. Conclusions: We report 30 cases of confirmed SARS-CoV-2 reinfections. The Lambda variant was the most common cause of the second infections, in concordance with its predominant circulation during Peru's second wave. This report describes the largest series of confirmed reinfections by SARS-CoV-2 in Latin America.We describe the epidemiological, clinical, and genomic characteristics of the confirmed cases of reinfection by severe acute respiratory syndrome coronavirus 2 in Lima and Callao, durante la segunda ola en Peru. The Lambda variant (C.37) was the most common cause of the second infections.