Evidence map›Paper›PMID 34756184›Full record

Observational studyLancet (London, England)2021

Effectiveness of a third dose of the BNT162b2 mRNA COVID-19 vaccine for preventing severe outcomes in Israel: an observational study.

Noam Barda, Noa Dagan, Cyrille Cohen, Miguel A Hernán, Marc Lipsitch, Isaac S Kohane, Ben Y Reis, Ran D Balicer

Open access · bronzeAbstract readObservational Study
PubMed Full text at PMC Publisher
In one paragraph

Observational study in Lancet (London, England), 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 572 papers, 3 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
572citing papers in PubMed, 3 pooled it
57.7field-weighted citation impact, top 1% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

572 citing papers in PubMed, 3 syntheses or guidelines pooled it, 935 citations in OpenAlex.

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  6. Reminders, but not monetary incentives, increase COVID-19 booster uptake.Proceedings of the National Academy of Sciences of the United States of America · 2023
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512 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

5 · Who and what money

Authors and funding

8 authors at 6 institutions in 2 countries.

Noam BardaClalit Research Institute, Innovation Division, Clalit Health Services, Tel Aviv, Israel; Software and Information Systems Engineering, Ben Gurion University of the Negev, Be'er Sheva, Israel; Department of Biomedical Informatics, Harvard Medical School, Boston, MA, USA; The Ivan and Francesca Berkowitz Family Living Laboratory Collaboration at Harvard Medical School and Clalit Research Institute, Boston, MA, USA.
Noa DaganClalit Research Institute, Innovation Division, Clalit Health Services, Tel Aviv, Israel; Software and Information Systems Engineering, Ben Gurion University of the Negev, Be'er Sheva, Israel; Department of Biomedical Informatics, Harvard Medical School, Boston, MA, USA; The Ivan and Francesca Berkowitz Family Living Laboratory Collaboration at Harvard Medical School and Clalit Research Institute, Boston, MA, USA.
Cyrille CohenThe Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel.
Miguel A HernánDepartment of Epidemiology, Harvard T H Chan School of Public Health, Boston, MA, USA; Department of Biostatistics, Harvard T H Chan School of Public Health, Boston, MA, USA; CAUSALab, Harvard T H Chan School of Public Health, Boston, MA, USA.
Marc LipsitchDepartment of Epidemiology, Harvard T H Chan School of Public Health, Boston, MA, USA; Department of Immunology and Infectious Diseases, Harvard T H Chan School of Public Health, Boston, MA, USA; Center for Communicable Disease Dynamics, Harvard T H Chan School of Public Health, Boston, MA, USA.
Isaac S KohaneDepartment of Biomedical Informatics, Harvard Medical School, Boston, MA, USA; The Ivan and Francesca Berkowitz Family Living Laboratory Collaboration at Harvard Medical School and Clalit Research Institute, Boston, MA, USA; Harvard Medical School, Boston, MA, USA.
Ben Y ReisThe Ivan and Francesca Berkowitz Family Living Laboratory Collaboration at Harvard Medical School and Clalit Research Institute, Boston, MA, USA; Predictive Medicine Group, Computational Health Informatics Program, Boston Children's Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA.
Ran D BalicerClalit Research Institute, Innovation Division, Clalit Health Services, Tel Aviv, Israel; School of Public Health, Faculty of Health Sciences, Ben Gurion University of the Negev, Be'er Sheva, Israel; The Ivan and Francesca Berkowitz Family Living Laboratory Collaboration at Harvard Medical School and Clalit Research Institute, Boston, MA, USA. Electronic address: rbalicer@clalit.org.il.
Family Research Institute · USHarvard University · USBar-Ilan University · ILBen-Gurion University of the Negev · ILCenter for Disease Dynamics, Economics & Policy · USClalit Health Services · IL

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundMany countries are experiencing a resurgence of COVID-19, driven predominantly by the delta (B.1.617.2) variant of SARS-CoV-2. In response, these countries are considering the administration of a third dose of mRNA COVID-19 vaccine as a booster dose to address potential waning immunity over time and reduced effectiveness against the delta variant. We aimed to use the data repositories of Israel's largest health-care organisation to evaluate the effectiveness of a third dose of the BNT162b2 mRNA vaccine for preventing severe COVID-19 outcomes.

methodsUsing data from Clalit Health Services, which provides mandatory health-care coverage for over half of the Israeli population, individuals receiving a third vaccine dose between July 30, 2020, and Sept 23, 2021, were matched (1:1) to demographically and clinically similar controls who did not receive a third dose. Eligible participants had received the second vaccine dose at least 5 months before the recruitment date, had no previous documented SARS-CoV-2 infection, and had no contact with the health-care system in the 3 days before recruitment. Individuals who are health-care workers, live in long-term care facilities, or are medically confined to their homes were excluded. Primary outcomes were COVID-19-related admission to hospital, severe disease, and COVID-19-related death. The third dose effectiveness for each outcome was estimated as 1 - risk ratio using the Kaplan-Meier estimator.

findings1 158 269 individuals were eligible to be included in the third dose group. Following matching, the third dose and control groups each included 728 321 individuals. Participants had a median age of 52 years (IQR 37-68) and 51% were female. The median follow-up time was 13 days (IQR 6-21) in both groups. Vaccine effectiveness evaluated at least 7 days after receipt of the third dose, compared with receiving only two doses at least 5 months ago, was estimated to be 93% (231 events for two doses vs 29 events for three doses; 95% CI 88-97) for admission to hospital, 92% (157 vs 17 events; 82-97) for severe disease, and 81% (44 vs seven events; 59-97) for COVID-19-related death.

interpretationOur findings suggest that a third dose of the BNT162b2 mRNA vaccine is effective in protecting individuals against severe COVID-19-related outcomes, compared with receiving only two doses at least 5 months ago.

fundingThe Ivan and Francesca Berkowitz Family Living Laboratory Collaboration at Harvard Medical School and Clalit Research Institute.

Indexed as

BNT162 VaccineImmunization, SecondaryVaccine EfficacyAdultAgedCOVID-19FemaleHumansIsraelMaleMass VaccinationMiddle AgedPandemicsPrognosisSARS-CoV-2BNT162 Vaccine

Identifiers

PMID34756184
PMCPMC8555967
OpenAlexW3210126657

What OpenQuestion holds

Textmetadata
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.