Healthcare-acquired coronavirus disease 2019 (COVID-19) is less symptomatic than community-acquired disease among healthcare workers

Abstract

Objective: We hypothesized healthcare workers (HCW) with high-risk exposures outside the healthcare system would have less asymptomatic coronavirus 2019 (COVID-19) disease and more symptoms than those without such exposures. Design: A longitudinal point prevalence study during August 17- September 4 2020 and December 2nd - 23rd. Setting: Community based teaching health system Participants: All HCS were invited to participate. Among HCW who acquired COVID-19, logistic regression models were used to evaluate the adjusted odds of asymptomatic disease using high-risk exposure outside the healthcare system as the explanatory variable. The number of symptoms between exposure groups was evaluated with the Wilcoxon rank-sum test. The risk of seropositivity among all HCS by work exposure was evaluated during both periods. Interventions: Survey and serological testing Result: Seroprevalence increased from 1.9% (95% CI 1.2% - 2.6%) to 13.7% (95% CI 11.9% - 15.5%) during the study. Only during Period 2 did HCW with the highest work exposure (versus low exposure) have an increased risk of seropositivity (RD 7% [95% CI 1% -13%]). Participants who had a high-risk exposure outside of work (compared to those without) had a decreased probability of asymptomatic disease (OR 0.38 [95% CI 0.16 – 0.86]) and demonstrated more symptoms (median of 3 [IQR 5] vs 1 [IQR 2]; P = 0.001). Conclusions Health care acquired COVID-19 increases the probability of asymptomatic or mild COVID-19 disease compared to community acquired disease. This suggests infection prevention strategies (including masks and eye protection) may be mitigating inoculum and supports the variolation theory in COVID-19.

P2/N95 respirators & surgical masks to prevent SARS-CoV-2 infection: Effectiveness & adverse effects

“…The majority of the studies were at high risk of bias (n=18/21) ( 16 , 24 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 ) primarily due to the potential for recall bias (e.g. use of self-report surveys), participation bias (e.g.…”

“…Further, adjustment for several confounding variables that might impact the likelihood of acquiring SARS-CoV-2 or AEs was lacking. Descriptions of SARS-CoV-2 activity in the community and the predominant variant (where greater activity in the community suggests greater infection risk ( 29 )), vaccination status of HCWs, clinical tasks performed by HCWs, use of respirator fit-testing and checking, type and use of additional PPE, comorbidities expected to exacerbate potential AEs (e.g. smoking and allergies ( 34 )), duration of wear and mitigation strategies used to reduce AE incidence or severity were inconsistently reported.…”

“…Twelve studies reported the rate of SARS-CoV-2 infection in HCWs who wore surgical masks compared to those who wore respirators ( 16 , 24 , 26 , 27 , 28 , 29 , 31 , 33 , 35 , 37 , 38 , 40 ). Overall, a similar percentage of HCWs wearing respirators (1,398/15,598 = 8.96%) and surgical masks (1,698/17,947 = 9.46%) acquired SARS-CoV-2 infection ( Fig 2 ).…”

Update Alert 6: Masks for Prevention of Respiratory Virus Infections, Including SARS-CoV-2, in Health Care and Community Settings

“…The update searches identified 492 citations. Two studies ( 3 , 4 ) on the use of masks and the prevention of SARS-CoV-2 done in a health care setting were added for this update; no new studies done in a community setting were identified through literature searches ( Supplement Tables 1 to 3 ).…”

“…On the basis of 3 observational studies ( 5–7 ) comparing N95 respirators with surgical masks for prevention of SARS-CoV-2 in health care settings, the strength of evidence was previously assessed as insufficient because of inconsistent effects across studies ( Supplement Table 4 ). One new cross-sectional study done in the United States found no statistically significant differences in risk for SARS-CoV-2 seropositivity between N95 respirator and surgical mask use ( 4 ). The study had methodological limitations, including potential recall bias and a 50% participation rate.…”