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The Effectiveness of the First Dose of BNT162b2 Vaccine in Reducing SARS-CoV-2 Infection: Real-World Evidence

18 Pages Posted: 20 Jan 2021

See all articles by Gabriel Chodick

Gabriel Chodick

Maccabi Healthcare Services - Maccabi Institute for Research & Innovation

Lilac Tene

Maccabi Institute for Research & Innovation, Maccabi Healthcare Services

Tal Patalone

Maccabi Institute for Research & Innovation, Maccabi Healthcare Services

Sivan Gazit

Maccabi Institute for Research & Innovation, Maccabi Healthcare Services

Amir Ben-Tov

Maccabi Institute for Research & Innovation, Maccabi Healthcare Services

Dani Cohen

Tel Aviv University

Khitam Muhsen

Tel Aviv University

More...

Abstract

Background: BNT162b2 vaccines showed high efficacy against COVID-19 in a randomised controlled phase-III trial. A vaccine effectiveness evaluation in real life settings is urgently needed, especially given the global disease surge. Hence, we assessed the short-term effectiveness of the first dose of BNT162b2-vaccine against SARS-CoV-2 infection. Given the BNT162b2 Phase-III results, we hypothesized that the cumulative incidence of SARS-CoV-2 infection among vaccinees will decline after 12 days following immunization compared to the incidence during the preceding days.

Methods: We conducted a retrospective cohort study using data from 2·6 million-member state-mandated health provider in Israel. Study population consisted of all members aged 16 or above years who were vaccinated with BNT162b2-vaccine between December/19/2020 and January/15/2021.   We collected information regarding medical history and positive SARS-CoV-2 polymerase chain reaction test from days after first dose to January/17/2021. Daily and cumulative infection rates in days 13-24 were compared to days 1-12 after first dose using Kaplan-Meier survival analysis and generalized linear models.

Findings: Data of 503,875 individuals (mean age 59·7 years SD=14·7, 47·8% males) were analysed, of whom 351,897 had 13-24 days of follow-up. The cumulative incidence of SARS-CoV-2 infection was 0·57% (n=2484) during days 1-12 and 0·27% (n=614) in days 13-24. A 51·4% relative risk reduction (RRR) was calculated in weighted-average daily incidence of SARS-CoV-2 infection from 43·41-per-100,000(SE=12·07) in days 1-12 to 21·08-per-100,000(SE=6·16) in days 13-24 following immunization. The decrement in incidence was evident from day 18 after first dose. Similar RRRs were calculated in individuals aged 60 or above (44.5%), younger individuals (50.2%), females (50.0%) and males (52.1%). Findings were similar in sub-populations and patients with various comorbidities.

Interpretation: We demonstrated an effectiveness of 51% of BNT162b2 vaccine against SARS-CoV-2 infection 13-24 days after immunization with the first dose. Immunization with the second dose should be continued to attain the anticipated protection.

Funding: No external funding was available for this study.

Declaration of Interests: We declare no competing interests.

Ethics Approval Statement: We obtained ethical approval from Maccabi Healthcare Services Ethics Committee.

Keywords: BNT162b2 vaccine, Effectiveness, SARS-Cov-2, Real-world evidence

Suggested Citation

Chodick, Gabriel and Tene, Lilac and Patalone, Tal and Gazit, Sivan and Ben-Tov, Amir and Cohen, Dani and Muhsen, Khitam, The Effectiveness of the First Dose of BNT162b2 Vaccine in Reducing SARS-CoV-2 Infection: Real-World Evidence. Available at SSRN: https://ssrn.com/abstract=3769977 or http://dx.doi.org/10.2139/ssrn.3769977

Gabriel Chodick (Contact Author)

Maccabi Healthcare Services - Maccabi Institute for Research & Innovation ( email )

Tel Aviv
Israel

Lilac Tene

Maccabi Institute for Research & Innovation, Maccabi Healthcare Services ( email )

Tal Patalone

Maccabi Institute for Research & Innovation, Maccabi Healthcare Services ( email )

Sivan Gazit

Maccabi Institute for Research & Innovation, Maccabi Healthcare Services ( email )

Amir Ben-Tov

Maccabi Institute for Research & Innovation, Maccabi Healthcare Services ( email )

Dani Cohen

Tel Aviv University

Khitam Muhsen

Tel Aviv University

Ramat Aviv
Tel-Aviv, 6997801
Israel

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