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

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 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 and genomic 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, 1,695 had 2 positive molecular tests with more than 90 days between them. 211 had both samples available for genomic analysis according to our selection criteria, these were retrieved and submitted to sequencing. 30 were confirmed to be SARS-CoV-2 reinfections having 2 different lineages in the 2 episodes. The variant Lambda (C.37) was the most common during the second infection, accounting for 19 (63.3%) of these. 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.