ABSTRACT
BackgroundMonitoring COVID-19 infection risk among health care workers (HCWs) is a public health priority. We examined the seroprevalence of SARS-CoV-2 among HCWs following the fall infection surge in Minnesota, and before and after COVID-19 vaccination. Additionally, we assessed demographic and occupational risk factors for SARS-CoV-2 infection. MethodsWe conducted two rounds of seroprevalence testing among a cohort of HCWs: samples in round 1 were collected from 11/22/20 - 02/21/21 and in round 2 from 12/18/20 - 02/15/21. Demographic and occupational exposures assessed with logistic regression were age, sex, healthcare role and setting, and number of children in the household. The primary outcome was SARS-CoV-2 IgG seropositivity. A secondary outcome, SARS-CoV-2 infection, included both seropositivity and self-reported SARS-CoV-2 test positivity. ResultsIn total, 459 HCWs were tested. 43/454 (9.47%) had a seropositive sample 1 and 75/423 (17.7%) had a seropositive sample 2. By time of sample 2 collection, 54% of participants had received at least one vaccine dose and seroprevalence was 13% among unvaccinated individuals. Relative to physicians, the odds of SARS-CoV-2 infection in other roles were increased (Nurse Practitioner: OR[95%CI] 1.93[0.57,6.53], Physicians Assistant: 1.69[0.38,7.52], Nurse: 2.33[0.94,5.78], Paramedic/EMTs: 3.86[0.78,19.0], other: 1.68[0.58,4.85]). The workplace setting was associated with SARS-CoV-2 infection (p=0.04). SARS-CoV-2 seroprevalence among HCWs reporting duties in the ICU vs. those working in an ambulatory clinic was elevated: OR[95%CI] 2.17[1.01,4.68]. ConclusionsSARS-CoV-2 seroprevalence in HCW increased during our study period which was consistent with community infection rates. HCW role and setting -- particularly working in the ICU -- is associated with higher risk for SARS-CoV-2 infection.
ABSTRACT
ImportanceTransmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is possible among symptom-free individuals and some patients are avoiding medically necessary healthcare visits for fear of becoming infected in the healthcare setting. Limited data are available on the point prevalence of SARS-CoV-2 infection in U.S. healthcare workers (HCW). ObjectiveTo estimate the prevalence of SARS-CoV-2 infection and to assess the acceptability of self-collected NPS among HCW. DesignCross-sectional convenience sample enrolled between April 20th and June 24th, 2020. We had >95% power to detect at least one positive test if the true underlying prevalence of SARS-CoV2 was [≥]1%. SettingThe metropolitan area surrounding Minneapolis and St. Paul, Minnesota. ParticipantsHCW free of self-reported upper respiratory symptoms were recruited. ExposuresParticipants completed questionnaires regarding demographics, household characteristics, personal protective equipment (PPE) utilization and comorbidities. OutcomesA participant self-collected nasopharyngeal swab (NPS) was obtained. SARS-CoV-2 infection was assessed via polymerase chain reaction. NPS discomfort was assessed on a scale of 1 (no discomfort) - 10 (extreme discomfort). NPS duration and depth into the nasopharynx, and willingness to perform future self-collections were assessed. ResultsAmong n=489 participants 80% were female and mean age{+/-}SD was 41{+/-}11. Participants reported being physicians (14%), nurse practitioners (8%), physicians assistants (4%), nurses (51%), medics (3%), or other which predominantly included laboratory technicians and administrative roles (22%). Exposure to a known/suspected COVID-19 case in the 14 days prior to enrollment was reported in 40% of participants. SARS-CoV-2 was not detected in any participant. The mean{+/-}SD discomfort level of the NPS was 4.5{+/-}2.0. Participants overwhelmingly reported that their self-swabs was [≥] the duration and depth of patient swabs they had previously performed. Over 95% of participants reported a willingness to repeat a self-collected NP swab in the future. Conclusions and RelevanceThe point prevalence of SARS-CoV-2 infection was likely <1% in a convenience sample of symptom-free Minnesota healthcare workers from April 20th and June 24th, 2020. Self-collected NP swabs are well-tolerated and a viable alternative to provider-collected swabs to preserve PPE. KEY POINTSO_ST_ABSQuestionsC_ST_ABSWhat is the point prevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection among symptom-free healthcare workers (HCW) and what is the acceptability of self-collected nasopharyngeal swabs (NPS) for SARS-CoV-2 infection ascertainment? FindingsSARS-CoV-2 was not detected in any of 489 HCWs studied. Self-collected NPS were well tolerated and over 95% of participants reported a willingness to repeat a self-collected NP swab in the future. MeaningThe point prevalence of SARS-CoV-2 infection was likely very low in a convenience sample of symptom-free Minnesota healthcare workers from April 20th and June 24th, 2020.
