COVID-19 in patients hospitalized and healthcare workers: what have changed after the first wave in a university hospital

Objective: To assess the COVID-19 frequency rates in hospitalized patients (HP) and healthcare workers (HCW), viral load inference, and the impact of vaccination and variants of concern (VOC) during the first pandemic wave. Methods: We evaluated the COVID-19 diagnostics at Hospital Sao Paulo, Brazil, from March 2020 to April 2021, in 10,202 samples (6,502 HP and 3,700 HCW) tested by RT-qPCR, inferring viral load by cycle threshold (Ct) values, and frequency rates. Results: SARS-CoV-2 was detected in 31.27% of individuals (32.23% HP and 29.80% HCW). The mean age of HP positives was 57.26 +/- 18.29 years (median = 59), with a mean Ct value of 25.55 +/- 6.07. Neither age nor Ct values in both groups have significantly differed during the first and second waves or even since the predominance of VOC P.1 on March 2021. Conclusions: The COVID-19 epidemic curves of HP and HCW accompanied the variations reported in Sao Paulo city, as well as the variation of hospitalization and occupancy of ICU beds. The VOC P.1 has no impact on the viral load, since its predominance in March 2021. The vaccination of HCW may have contributed to a decrease in the positivity rates, although more studies will provide a better understanding of the impact of immunization on the COVID-19 pandemic.