Two-Dose Severe Acute Respiratory Syndrome Coronavirus 2 Vaccine Effectiveness With Mixed Schedules and Extended Dosing Intervals: Test-Negative Design Studies From British Columbia and Quebec, Canada

作者：Danuta M. Skowronski, Yossi Febriani, Moussa Ouakki, Solmaz Setayeshgar, Shiraz El Adam, Macy Zou, Denis Charles Talbot, Natalie Prystajecky, John R. Tyson, Rodica Gilca, Nicholas Brousseau, Geneviève Deceuninck, Eleni Galanis, Christopher D. Fjell, Hind Sbihi, Élise Fortin, Sapha Barkati, Chantal Sauvageau, Monika Naus, David M. Patrick, Bonnie Henry, Linda Hoang, Philippe De Wals, Christophe Garenc, Alex Carignan, Mélanie Drolet, Agatha N. Jassem, Manish Sadarangani, Marc Brisson, Mel Krajden, Gaston De Serres · 发表于：Clinical Infectious Diseases · 年份：2022 · DOI：10.1093/cid/ciac290 · 被引用次数：138 · 研究领域：SARS-CoV-2 and COVID-19 Research、SARS-CoV-2 detection and testing、Animal Virus Infections Studies

BACKGROUND: The Canadian coronavirus disease 2019 (COVID-19) immunization strategy deferred second doses and allowed mixed schedules. We compared 2-dose vaccine effectiveness (VE) by vaccine type (mRNA and/or ChAdOx1), interval between doses, and time since second dose in 2 of Canada's larger provinces. METHODS: Two-dose VE against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or hospitalization among adults ≥18 years, including due to Alpha, Gamma, and Delta variants of concern (VOCs), was assessed ≥14 days postvaccination by test-negative design studies separately conducted in British Columbia and Quebec, Canada, between 30 May and 27 November (epi-weeks 22-47) 2021. RESULTS: In both provinces, all homologous or heterologous mRNA and/or ChAdOx1 2-dose schedules were associated with ≥90% reduction in SARS-CoV-2 hospitalization risk for ≥7 months. With slight decline from a peak of >90%, VE against infection was ≥80% for ≥6 months following homologous mRNA vaccination, lower by ∼10% when both doses were ChAdOx1 but comparably high following heterologous ChAdOx1 + mRNA receipt. Findings were similar by age group, sex, and VOC. VE was significantly higher with longer 7-8-week versus manufacturer-specified 3-4-week intervals between mRNA doses. CONCLUSIONS: Two doses of any mRNA and/or ChAdOx1 combination gave substantial and sustained protection against SARS-CoV-2 hospitalization, spanning Delta-dominant circulation. ChAdOx1 VE against infection was imp...