Infection control, occupational and public health measures including mRNA-based vaccination against SARS-CoV-2 infections to protect healthcare workers from variants of concern: A 14-month observational study using surveillance data.

Autor:	Yassi A; School of Population and Public Health (SPPH), University of British Columbia (UBC), Vancouver, British Columbia (BC), Canada.; Physician Occupational Safety and Health, Vancouver Coastal Health (VCH), Vancouver, BC, Canada.; Department of Pathology and Laboratory Medicine, Vancouver Coastal Health (VCH), Vancouver, Canada., Grant JM; Physician Occupational Safety and Health, Vancouver Coastal Health (VCH), Vancouver, BC, Canada.; Department of Pathology and Laboratory Medicine, Vancouver Coastal Health (VCH), Vancouver, Canada.; Division of Medical Microbiology and Infection Prevention, VCH, Vancouver, Canada.; Division of Medical Microbiology, Department of Laboratory Medicine and Pathology, UBC, Vancouver, Canada., Lockhart K; School of Population and Public Health (SPPH), University of British Columbia (UBC), Vancouver, British Columbia (BC), Canada., Barker S; School of Population and Public Health (SPPH), University of British Columbia (UBC), Vancouver, British Columbia (BC), Canada., Sprague S; Employee Safety, Health and Wellness, VCH, Vancouver, Canada., Okpani AI; School of Population and Public Health (SPPH), University of British Columbia (UBC), Vancouver, British Columbia (BC), Canada.; Physician Occupational Safety and Health, Vancouver Coastal Health (VCH), Vancouver, BC, Canada., Wong T; Department of Pathology and Laboratory Medicine, Vancouver Coastal Health (VCH), Vancouver, Canada.; Division of Medical Microbiology and Infection Prevention, VCH, Vancouver, Canada.; Division of Medical Microbiology, Department of Laboratory Medicine and Pathology, UBC, Vancouver, Canada., Daly P; School of Population and Public Health (SPPH), University of British Columbia (UBC), Vancouver, British Columbia (BC), Canada.; Public Health, VCH, Vancouver, Canada., Henderson W; Department of Medicine, UBC, Vancouver, Canada.; Vancouver Acute, Emergency Operations Centre, VCH, Vancouver, Canada., Lubin S; Physician Occupational Safety and Health, Vancouver Coastal Health (VCH), Vancouver, BC, Canada., Kim Sing C; Medicine, Quality and Safety, VCH, Vancouver, Canada.; Department of Emergency Medicine, UBC, Vancouver, Canada.
Jazyk:	angličtina
Zdroj:	PloS one [PLoS One] 2021 Jul 16; Vol. 16 (7), pp. e0254920. Date of Electronic Publication: 2021 Jul 16 (Print Publication: 2021).
DOI:	10.1371/journal.pone.0254920
Abstrakt:	Background: We evaluated measures to protect healthcare workers (HCWs) in Vancouver, Canada, where variants of concern (VOC) went from <1% VOC in February 2021 to >92% in mid-May. Canada has amongst the longest periods between vaccine doses worldwide, despite Vancouver having the highest P.1 variant rate outside Brazil. Methods: With surveillance data since the pandemic began, we tracked laboratory-confirmed SARS-CoV-2 infections, positivity rates, and vaccine uptake in all 25,558 HCWs in Vancouver Coastal Health, by occupation and subsector, and compared to the general population. Cox regression modelling adjusted for age and calendar-time calculated vaccine effectiveness (VE) against SARS-CoV-2 in fully vaccinated (≥ 7 days post-second dose), partially vaccinated infection (after 14 days) and unvaccinated HCWs; we also compared with unvaccinated community members of the same age-range. Findings: Only 3.3% of our HCWs became infected, mirroring community rates, with peak positivity of 9.1%, compared to 11.8% in the community. As vaccine coverage increased, SARS-CoV-2 infections declined significantly in HCWs, despite a surge with predominantly VOC; unvaccinated HCWs had an infection rate of 1.3/10,000 person-days compared to 0.89 for HCWs post first dose, and 0.30 for fully vaccinated HCWs. VE compared to unvaccinated HCWs was 37.2% (95% CI: 16.6-52.7%) 14 days post-first dose, 79.2% (CI: 64.6-87.8%) 7 days post-second dose; one dose provided significant protection against infection until at least day 42. Compared with community infection rates, VE after one dose was 54.7% (CI: 44.8-62.9%); and 84.8% (CI: 75.2-90.7%) when fully vaccinated. Interpretation: Rigorous droplet-contact precautions with N95s for aerosol-generating procedures are effective in preventing occupational infection in HCWs, with one dose of mRNA vaccination further reducing infection risk despite VOC and transmissibility concerns. Delaying second doses to allow more widespread vaccination against severe disease, with strict public health, occupational health and infection control measures, has been effective in protecting the healthcare workforce. Competing Interests: The authors have declared that no competing interests exist.
Databáze:	MEDLINE
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