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SARS-CoV-2 mRNA Vaccine Effectiveness in Health Care Workers by Dosing Interval and Time Since Vaccination: Test-Negative Design, British Columbia, Canada.
El Adam, Shiraz; Zou, Macy; Kim, Shinhye; Henry, Bonnie; Krajden, Mel; Skowronski, Danuta M.
Afiliación
  • El Adam S; BC Centre for Disease Control, Communicable Diseases and Immunization Services, Vancouver, British Columbia, Canada.
  • Zou M; Data and Analytics Services, BC Centre for Disease Control, Vancouver, British Columbia, Canada.
  • Kim S; BC Centre for Disease Control, Communicable Diseases and Immunization Services, Vancouver, British Columbia, Canada.
  • Henry B; School of Population and Public Health, University of British Columbia, Vancouver, British Columbia, Canada.
  • Krajden M; Office of the Provincial Health Officer, Ministry of Health, Victoria, British Columbia, Canada.
  • Skowronski DM; Public Health Laboratory, BC Centre for Disease Control, Vancouver, British Columbia, Canada.
Open Forum Infect Dis ; 9(5): ofac178, 2022 May.
Article en En | MEDLINE | ID: mdl-35531384
Background: One- and two-dose mRNA vaccine effectiveness (VE) estimates against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection by dosing interval and time since vaccination were assessed among healthcare workers (HCWs) in publicly funded acute and community (nonresidential) healthcare facilities in British Columbia, Canada. Methods: A test-negative design was used with controls matched to cases (6:1) on epidemiological week of SARS-CoV-2 test date. mRNA vaccination was defined by receipt of the first dose ≥21 days or second dose ≥14 days before the test date. HCWs ≥18 years old tested for SARS-CoV-2 between epi-weeks 3 and 39 (January 17-October 2, 2021) were included, when varying dosing intervals and a mix of circulating variants of concern contributed, including Delta dominance provincially from epi-week 31 (August 1). Results: Single- and two-dose analyses included 1265 and 1246 cases, respectively. The median follow-up period (interquartile range) was 49 (34-69) days for single-dose and 89 (61-123) days for two-dose recipients, with 12%, 31%, and 58% of second doses given 3-5, 6, or ≥7 weeks after the first. Adjusted mRNA VE against SARS-CoV-2 was 71% (95% CI, 66%-76%) for one dose and 90% (95% CI, 88%-92%) for two doses, similar to two heterologous mRNA doses (92%; 95% CI, 86%-95%). Two-dose VE remained >80% at ≥28 weeks post-second dose. Two-dose VE was consistently 5%-7% higher with a ≥7-week vs 3-5-week interval between doses, but with overlapping confidence intervals. Conclusions: Among HCWs, we report substantial single-dose and strong and sustained two-dose mRNA vaccine protection, with the latter maintained for at least 7 months. These findings support a longer interval between doses, with global health and equity implications.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Tipo de estudio: Evaluation_studies Aspecto: Equity_inequality Idioma: En Revista: Open Forum Infect Dis Año: 2022 Tipo del documento: Article País de afiliación: Canadá Pais de publicación: Estados Unidos
Texto completo
Añadir a Mi BVS
Imprimir
XML
PubMed Links
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Tipo de estudio: Evaluation_studies Aspecto: Equity_inequality Idioma: En Revista: Open Forum Infect Dis Año: 2022 Tipo del documento: Article País de afiliación: Canadá Pais de publicación: Estados Unidos