Long-term duration of protection of ancestral-strain monovalent vaccines and effectiveness of the bivalent BA.1 boosters against COVID-19 hospitalisation during a period of BA.5, BQ.1, CH.1.1. and XBB.1.5 circulation in England
This article has been Reviewed by the following groups
Listed in
- Evaluated articles (PREreview)
Abstract
Background
Bivalent BA.1 booster vaccines were offered to adults aged 50 years and older and clinically vulnerable individuals as part of the autumn COVID-19 booster vaccination programme 2022 in England.
Methods
A test-negative case-control study was used to estimate the duration of protection of the monovalent vaccines against hospitalisation as compared to those unvaccinated. In addition, the incremental VE of the bivalent BA.1 booster vaccines was estimated relative to those with waned immunity where the last dose was at least 6 months prior amongst those aged 50 years and older.
Findings
The protection conferred by the monovalent vaccines was well maintained long-term: absolute VE against hospitalisation amongst those aged 65 years and older who had received at least 3 doses plateaued from 6 months after the last dose at around 50%. Incremental VE (in addition to the protection from earlier vaccines) of the bivalent BA.1 boosters against hospitalisation peaked at 53.0% (95% C.I.; 47.9-57.5%) (equivalent to an absolute VE of approximately 75%) before waning to around 35.9% (95% C.I.; 31.4-40.1%) after 10 or more weeks.
Interpretation
This study provides evidence of the long-term duration of protection of the monovalent vaccines, suggesting individuals at lower risk of severe disease who did not receive a booster in autumn 2022 may not require regular re-vaccination. Furthermore, this study finds good evidence that the bivalent BA.1 booster vaccines are highly effective against hospitalisation amongst those aged 50 years and older with the sub-lineages of Omicron present in the autumn/winter of 2022 in England.
Funding
None.
Article activity feed
-
This Zenodo record is a permanently preserved version of a PREreview. You can view the complete PREreview at https://prereview.org/reviews/7800482.
The main findings of this paper regarding the association between vaccine effectiveness and hospitalization of people aged 65 years or older in terms of monovalent vaccine protection. Their case-control study found absolute vaccine effectiveness through 3 doses of monovalent vaccines for people of this age group for 6 months at a time.
The paper was clear and adequate, suggesting further evidence of the effectiveness of boosters in preventing hospitalization.
Competing interests
The author declares that they have no competing interests.
-
