COVID-19 risk among HCWs according to patient exposure, mask type

Editor's Note

This study from Switzerland finds that COVID-19 positivity in healthcare workers (HCWs) was associated with cumulative patient exposure, which could be modulated with the use of respirator masks.

Of 2,919 HCWs included in the study, 749 were infected with COVID-19. Positivity was 13% in HCWs without patient exposure. For HCWs with patient exposure, positivity was 21% for those using respirator masks and 35% for those wearing surgical/mixed masks.

In multivariate analysis, variables associated with COVID-19 infection included:

• a positive household contact (Odds Ratio [OR], 7.79)
• exposure to patients (OR, 1.20)
• respirator use (OR, 0.56)
• COVID-19 vaccination (OR, 0.55).

The odds of being COVID-19 positive were reduced by more than 40% in HCWs using respirators, irrespective of cumulative exposure, even after adjusting for work and nonwork related covariables. Whether the findings are applicable to newer COVID-19 variants, which are more contagious and less neutralized by vaccines, remains to be seen, the researchers note.