Waning of first- and second-dose ChAdOx1 and BNT162b2 COVID-19 vaccinations: a pooled target trial study of 12.9 million individuals in England, Northern Ireland, Scotland and Wales.
Int J Epidemiol
; 2022 Oct 22.
Article
in English
| MEDLINE | ID: covidwho-2231783
ABSTRACT
BACKGROUND:
Several SARS-CoV-2 vaccines have been shown to provide protection against COVID-19 hospitalization and death. However, some evidence suggests that notable waning in effectiveness against these outcomes occurs within months of vaccination. We undertook a pooled analysis across the four nations of the UK to investigate waning in vaccine effectiveness (VE) and relative vaccine effectiveness (rVE) against severe COVID-19 outcomes.METHODS:
We carried out a target trial design for first/second doses of ChAdOx1(Oxford-AstraZeneca) and BNT162b2 (Pfizer-BioNTech) with a composite outcome of COVID-19 hospitalization or death over the period 8 December 2020 to 30 June 2021. Exposure groups were matched by age, local authority area and propensity for vaccination. We pooled event counts across the four UK nations.RESULTS:
For Doses 1 and 2 of ChAdOx1 and Dose 1 of BNT162b2, VE/rVE reached zero by approximately Days 60-80 and then went negative. By Day 70, VE/rVE was -25% (95% CI -80 to 14) and 10% (95% CI -32 to 39) for Doses 1 and 2 of ChAdOx1, respectively, and 42% (95% CI 9 to 64) and 53% (95% CI 26 to 70) for Doses 1 and 2 of BNT162b2, respectively. rVE for Dose 2 of BNT162b2 remained above zero throughout and reached 46% (95% CI 13 to 67) after 98 days of follow-up.CONCLUSIONS:
We found strong evidence of waning in VE/rVE for Doses 1 and 2 of ChAdOx1, as well as Dose 1 of BNT162b2. This evidence may be used to inform policies on timings of additional doses of vaccine.
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Type of study:
Cohort study
/
Experimental Studies
/
Prognostic study
/
Randomized controlled trials
/
Reviews
Topics:
Vaccines
Language:
English
Year:
2022
Document Type:
Article
Affiliation country:
Ije
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