Mapping the viral battlefield: SARS-CoV-2 infection dynamics among healthcare workers in Brazil

Abstract

Background: Understanding the dynamics of SARS-CoV-2 viral infection and factors associated with in-hospital transmission rates among healthcare workers (HCW) is crucial for their protection. Brazil experienced high mortality rates due to COVID-19, and limited data are available on transmission of SARS-CoV-2 infection among HCW. This cohort study aimed to assess the dynamic of SARS-CoV-2 infections in HCW from two tertiary hospitals in central Brazil, one of them a Reference Hospital for COVID-19.

Methods: From May 2020 to January 2021, 554 HCW directly involved with COVID-19 care were followed through 12 biweekly visits. During these visits, blood, nasal, and oropharyngeal samples were collected, and participants underwent interviews. SARS-CoV-2 detection was carried out using RT-qPCR, while the assessment of seroprevalence was based on IgG detection. Additionally, 35 positive samples underwent viral whole-genome sequencing.

Results: The infection prevalence, as per RT-qPCR, was 28.5% (24.9-32.4), reflecting an overall attack rate ranging from 0.5% to 9.5%, marked by two peaks in August and December 2020. Oligosymptomatic and asymptomatic infections accounted for 14% of prevalent infections. The seroprevalence rate stood at 25.8%. The hospitalization rate was 8.2%, with a fatality rate of 1.3%. Risk factors associated with a positive diagnosis of COVID-19 included being male, working at the referral hospital, having a graduate-education level, and using hydroxychloroquine and zinc for prevention or treatment. One reinfection was identified. Absenteeism was 56.6%. The infection dynamics mirrored the pattern observed in the general population.

Conclusion: One-third of the professionals in the followed cohort were infected. Being male, working in a COVID-19 referral center, having a low level of education, and using medications for preventive treatment represented risk factors. Healthcare workers at the COVID-19 referral hospital exhibited a higher incidence rate compared to those at the non-referral hospital, increasing the plausibility that some of the infections occur in the hospital environment.

Keywords: Asymptomatic infection; COVID-19; Epidemiology; Healthcare worker; SARS-CoV-2.

Fig. 1

Incidence rates of SARS-CoV-2 infection and the seroprevalence of SARS-CoV-2-specific IgG among HCW in two tertiary hospitals located in the city of Campo Grande, Brazil, from May 2020 to January 2021. In light blue, the figure presents the incidence rate of SARS-CoV-2 infection. The dark blue, the figure presents the seroprevalence of SARS-CoV-2-specific IgG. Correlation analyses were conducted using the Spearman's rank correlation test

Fig. 2

Dynamics of SARS-CoV-2 infection in HCWs (columns) versus confirmed cases of Covid-19 in the population of Campo Grande, Mato Grosso do Sul, Brazil (blue line). A Distribution of SARS-CoV-2 infection cases in the HCW cohort from the two evaluated hospitals in the present study. B Distribution of SARS-CoV-2 infection cases in HCWs from Campo Grande. Data expressed in absolute numbers per epidemiological week. Non-primary data were obtained from the Epidemiological Bulletins of the State Health Department of Mato Grosso do Sul during the study period. Correlation analyses were conducted using the Spearman's rank correlation test

Fig. 3

Mortality (‰) and lethality (%) rates of COVID-19 among HCW in two tertiary hospitals located in the city of Campo Grande, Brazil, from May 2020 to January 2021. Hospital A, which serves as a reference for COVID-19, and Hospital B, which is non-reference for COVID-19