[COVID-19: modification of the risk of infection and disease development associated with the performance of blended work.]

de la Rosa Ruiz, David; Guillén Astete, Carlos Antonio

OBJECTIVE The health crisis caused by COVID-19 has had an economic impact at all levels and the labor market has been shaken by the pandemic. Companies have had to adapt to new work models and have had to decide between face-to-face, teleworking, or mixed models without conclusive scientific evidence on the impact on transmission. To determine the change in the risk of SARS-CoV-2 infection and the development of disease associated with the performance of blended work with respect to remote work and the general population in a non-healthcare company while respecting the measures of social distancing, use of masks and hand hygiene. METHODS Observational ecological study followed by a retrospective cohort study. Data were collected on the total daily cases and incidence of COVID-19 between September 1, 2020 and April 30, 2021 from the population of a non-healthcare company and the reference population of the Community of Madrid. Analysis was also performed in two 30-day periods on the same population differentiated by the existence of fully remote or blended work. The statistical analysis was performed by determining the Chi2 distribution (χ2) and calculating the Odds Ratio (OR). RESULTS The average number of employees during the study period was 642 (30.55% women). The reference population was 6,745,591 people (52.16% women). The number of people aged between 20 and 69 years was 4,520,116 (51.67% women). The incidence in the period (Ip) in the study population was 9.5%. The Ip in the Community of Madrid was 7.81%. No statistical differences were found OR 1.23 (95% CI 0.95-1.61) χ2=2.55 p-value 0.11. Ip in the population of the Community between 20 and 69 years was 8.84% OR 1.08 (95% CI 0.83-1.41) χ2=0.35 p-value 0.556. In the comparison performed in the study population, no statistically significant differences were found between both periods OR 0.59 (IC95% 0.26-1.37) χ2=1.53 p-value 0.216. CONCLUSIONS Based on the data analyzed, we found no statistically significant evidence to show that performing semi-distance work with security measures in a non-healthcare company increases the risk of SARS-CoV-2 infection and the development of disease.