Effective of covid 19 vaccination against risk of aymptomotic infection

Manuscript Click here to view linked References rr ev iew ed Effectiveness of Covid-19 vaccination against risk of symptomatic infection, hospitalization, and death up to months: a Swedish total-population cohort study Peter Nordström, MD, PhD, Marcel Ballin, MSc., Anna Nordström, MD, PhD Department of Community Medicine and Rehabilitation, Unit of Geriatric Medicine, Umể University, Umể, Sweden (Peter Nordstrưm and Marcel Ballin) Department of Public Health and Clinical Medicine, Section of Sustainable Health, Umeå University, Umeå, Sweden (Marcel Ballin and Anna Nordström) School of Sport Sciences, UiT the Arctic University of Norway, Tromsø, Norway (Anna ee Nordström) ot p Abstract word count: 299 Main text word count: 3467 Corresponding author: tn Peter Nordström, Professor Unit of Geriatric Medicine Pr ep rin Department of Community Medicine and Rehabilitation Umeå University 90187 Umeå Sweden Phone: +4670 899 65 99 E-mail: peter.nordstrom@umu.se This preprint research paper has not been peer reviewed Electronic copy available at: https://ssrn.com/abstract=3949410 rr ev iew ed Abstract Background: Whether vaccine effectiveness against Coronavirus disease 2019 (Covid-19) lasts longer than months is unclear Methods: A retrospective cohort study was conducted using Swedish nationwide registries The cohort comprised 842,974 pairs (N=1,684,958), including individuals vaccinated with doses of ChAdOx1 nCoV-19, mRNA-1273, or BNT162b2, and matched unvaccinated individuals Cases of symptomatic infection and severe Covid-19 (hospitalization or 30-day mortality after confirmed infection) were collected from 12 January to October 2021 Findings: Vaccine effectiveness of BNT162b2 against infection waned progressively from 92% (95% CI, 92-93, P