The dynamics underlying severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reinfection remain poorly understood. We identified a small cluster of patients in Brazil who experienced 2 episodes of coronavirus disease (COVID-19) in March and late May 2020. In the first episode, patients manifested an enhanced innate response compared with healthy persons, but neutralizing humoral immunity was not fully achieved. The second episode was associated with different SARS-CoV-2 strains, higher viral loads, and clinical symptoms. Our finding that persons with mild COVID-19 may have controlled SARS-CoV-2 replication without developing detectable humoral immunity suggests that reinfection is more frequent than supposed, but this hypothesis is not well documented.

1st April 2021 • comment

The SARS-CoV-2 lineage B.1.1.28 has been evolving in Brazil since February 2020, but the recent emergence of sub-lineages with convergent mutations in the spike (S) protein raises concern about the potential impact on viral infectivity and immune escape. The lineage P.1 (alias of B. is an emerging variant that harbours several amino acid mutations including S:K417T, S:E484K, and S:N501Y. This report describes the first confirmed case of reinfection with the P.1 lineage in a 29-years-old female resident in the Amazonas state, Brazil, previously infected with a B.1 lineage virus.

9th February 2021 • comment

The dynamics underlying severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) reinfection remains poorly understood. We added to the registered case reports of reinfection in USA, Belgium/Netherlands, Ecuador and Hong Kong, a small cluster of individuals with two episodes of 2019 coronavirus disease (COVID-19). Virus genomic analysis and the host immune response were used to characterize this group.

8th February 2021 • comment