Clinical Impact of COVID-19 by P.1 SARS-CoV-2 Lineage

Since the first report of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variant of concern (VOC) P.1 in Manaus, Brazil, a rapid spread of this lineage across the country has been observed. Recent studies indicate that this variant is associated with higher transmissibility; it is not known whether it is associated with clinical severity and higher mortality rates.

This is a retrospective cohort study carried out at Hospital de Clínicas de Porto Alegre. Adult patients aged 18 years or more and 65 years or less who were admitted to the hospital due to symptomatic COVID-19 from June 2020 to May 2021 and had a reverse transcriptase-polymerase chain reaction (RT-PCR) cycle threshold value for either SARS-CoV-2 N1 or N2 target ≤ 25 were eligible to the study. Samples from 86 patients (43 from June 2020 to November 2020 and 43 from February 2021 to May 2021) were sequenced for further evaluation. These dates were defined since the emergence of P.1 lineage in late January.

Clinical data regarding ventilatory support, date of onset of symptoms, laboratory findings and mortality were collected from each patient. This retrospective cohort aims to assess whether the number of days needed for supplementary oxygen either by noninvasive ventilation or high-flow nasal cannula from onset of symptoms differs among patients infected with the P.1 SARS-CoV-2 variant and those infected with other variants.