Preprints with The Lancet is part of SSRN´s First Look, a place where journals identify content of interest prior to publication. Authors have opted in at submission to The Lancet family of journals to post their preprints on Preprints with The Lancet. The usual SSRN checks and a Lancet-specific check for appropriateness and transparency have been applied. Preprints available here are not Lancet publications or necessarily under review with a Lancet journal. These preprints are early stage research papers that have not been peer-reviewed. The findings should not be used for clinical or public health decision making and should not be presented to a lay audience without highlighting that they are preliminary and have not been peer-reviewed. For more information on this collaboration, see the comments published in The Lancet about the trial period, and our decision to make this a permanent offering, or visit The Lancet´s FAQ page, and for any feedback please contact preprints@lancet.com.
BNT162B2 mRNA Covid-19 Vaccine Effectiveness in the Prevention of SARS-CoV-2 Infection and Symptomatic Disease in the Medium - to Long-Term: A Retrospective Cohort Study
19 Pages Posted: 28 Jul 2021
More...Abstract
Introduction: To combat the COVID-19 pandemic, a mass vaccination campaign was initiated in Italy on December 27, 2020. The vaccine available to immunize Italian healthcare workers (HCWs) was the BNT162b2 mRNA COVID-19 vaccine (Comirnaty). Many studies have shown the high effectiveness of this vaccine in preventing infection and symptomatic disease in the fully immunized.
Methods: This study evaluated the effectiveness of the vaccine against documented SARS-CoV-2 infection and symptomatic diseases in the medium- to long-term. HCWs at Bari Policlinico University-Hospital (Italy) who completed the vaccination schedule were matched with HCWs who had refused vaccination; the two groups were followed-up for 5 months (January–May 2021).
Findings: Vaccine effectiveness (VE) against infection was 97·7% (95·4–99·0%) at 14–34 days after the first dose, and 94·8% (87·0–97·8%), 83·0% (65·0–92·0%), and 81·0% (42·0-94·0%) at 14–41, 42–69, and >69 days, respectively, after the second dose. The estimated VE for documented symptomatic disease was 99·2% (96·4–99·8%) at 14–34 days after the first dose and 97·2% (90·3–99·2%), 85·0% (63·0–94·2%), and 88·0% (42·0–97·6%) at 14–41, 42–69, and >69 days, respectively, after the second dose.
Interpretations: The demonstrated effectiveness and safety of the BNT162b2 mRNA vaccine over the medium- to long-term provides further evidence that it is an essential weapon in ending the COVID-19 pandemic. Efforts to increase vaccination rates should be strengthened, including mandatory vaccination for HCWs and greater incentives to increase vaccine acceptance by the general population.
Funding: None to declare.
Declaration of Interest: None to declare.
Ethical Approval: The research protocol was approved by Apulian Epidemiological Observatory and all human participants gave written informed consent.
Keywords: COVID-19; documented infection; vaccine effectiveness; healthcare workers
Suggested Citation: Suggested Citation