Effectiveness of mRNA BNT162b2 COVID-19 vaccine up to 6 months in a large integrated health system in the USA : a retrospective cohort study

Copyright © 2021 Elsevier Ltd. All rights reserved..

BACKGROUND: Vaccine effectiveness studies have not differentiated the effect of the delta (B.1.617.2) variant and potential waning immunity in observed reductions in effectiveness against SARS-CoV-2 infections. We aimed to evaluate overall and variant-specific effectiveness of BNT162b2 (tozinameran, Pfizer-BioNTech) against SARS-CoV-2 infections and COVID-19-related hospital admissions by time since vaccination among members of a large US health-care system.

METHODS: In this retrospective cohort study, we analysed electronic health records of individuals (≥12 years) who were members of the health-care organisation Kaiser Permanente Southern California (CA, USA), to assess BNT162b2 vaccine effectiveness against SARS-CoV-2 infections and COVID-19-related hospital admissions for up to 6 months. Participants were required to have 1 year or more previous membership of the organisation. Outcomes comprised SARS-CoV-2 PCR-positive tests and COVID-19-related hospital admissions. Effectiveness calculations were based on hazard ratios from adjusted Cox models. This study was registered with ClinicalTrials.gov, NCT04848584.

FINDINGS: Between Dec 14, 2020, and Aug 8, 2021, of 4 920 549 individuals assessed for eligibility, we included 3 436 957 (median age 45 years [IQR 29-61]; 1 799 395 [52·4%] female and 1 637 394 [47·6%] male). For fully vaccinated individuals, effectiveness against SARS-CoV-2 infections was 73% (95% CI 72-74) and against COVID-19-related hospital admissions was 90% (89-92). Effectiveness against infections declined from 88% (95% CI 86-89) during the first month after full vaccination to 47% (43-51) after 5 months. Among sequenced infections, vaccine effectiveness against infections of the delta variant was high during the first month after full vaccination (93% [95% CI 85-97]) but declined to 53% [39-65] after 4 months. Effectiveness against other (non-delta) variants the first month after full vaccination was also high at 97% (95% CI 95-99), but waned to 67% (45-80) at 4-5 months. Vaccine effectiveness against hospital admissions for infections with the delta variant for all ages was high overall (93% [95% CI 84-96]) up to 6 months.

INTERPRETATION: Our results provide support for high effectiveness of BNT162b2 against hospital admissions up until around 6 months after being fully vaccinated, even in the face of widespread dissemination of the delta variant. Reduction in vaccine effectiveness against SARS-CoV-2 infections over time is probably primarily due to waning immunity with time rather than the delta variant escaping vaccine protection.

FUNDING: Pfizer.

Errataetall:

CommentIn: Lancet. 2021 Oct 16;398(10309):1382-1383. - PMID 34656213

Medienart:

E-Artikel

Erscheinungsjahr:

2021

Erschienen:

2021

Enthalten in:

Zur Gesamtaufnahme - volume:398

Enthalten in:

Lancet (London, England) - 398(2021), 10309 vom: 16. Okt., Seite 1407-1416

Sprache:

Englisch

Beteiligte Personen:

Tartof, Sara Y [VerfasserIn]
Slezak, Jeff M [VerfasserIn]
Fischer, Heidi [VerfasserIn]
Hong, Vennis [VerfasserIn]
Ackerson, Bradley K [VerfasserIn]
Ranasinghe, Omesh N [VerfasserIn]
Frankland, Timothy B [VerfasserIn]
Ogun, Oluwaseye A [VerfasserIn]
Zamparo, Joann M [VerfasserIn]
Gray, Sharon [VerfasserIn]
Valluri, Srinivas R [VerfasserIn]
Pan, Kaije [VerfasserIn]
Angulo, Frederick J [VerfasserIn]
Jodar, Luis [VerfasserIn]
McLaughlin, John M [VerfasserIn]

Links:

Volltext

Themen:

BNT162 Vaccine
COVID-19 Vaccines
Evaluation Study
Journal Article
N38TVC63NU
RNA, Messenger
Research Support, Non-U.S. Gov't

Anmerkungen:

Date Completed 03.11.2021

Date Revised 17.12.2022

published: Print-Electronic

ClinicalTrials.gov: NCT04848584

CommentIn: Lancet. 2021 Oct 16;398(10309):1382-1383. - PMID 34656213

Citation Status MEDLINE

doi:

10.1016/S0140-6736(21)02183-8

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM331601044