Comparative effectiveness of bivalent BA.4-5 or BA.1 mRNA booster vaccines among immunocompromised individuals across three Nordic countries: A nationwide cohort study.
J Infect
; 89(4): 106261, 2024 Oct.
Article
in En
| MEDLINE
| ID: mdl-39218308
ABSTRACT
OBJECTIVES:
To estimate the effectiveness and waning of the bivalent BA.4-5 or BA.1 mRNA booster vaccine against Covid-19-related hospitalization and death in immunocompromised individuals.METHODS:
Nationwide analyses across Nordic countries from 1 September 2022 to 31 October 2023 using a matched cohort design. Individuals boosted with a BA.4-5 or BA.1 vaccine were matched 11 with unboosted individuals. The outcomes of interest were country-combined vaccine effectiveness (VE) estimates against Covid-19-related hospitalization and death at day 270 of follow-up. Waning was assessed in 45-day intervals.RESULTS:
A total of 352,762 BA.4-5 and 191,070 BA.1 booster vaccine doses were included. At day 270, the comparative VE against Covid-19-related hospitalization was 34.2% (95% CI, 7.1% to 61.3%) for the bivalent BA.4-5 vaccine and 42.6% (95% CI, 31.3% to 53.9%) for the BA.1 vaccine compared with matched unboosted. The comparative VE against Covid-19-related death was 53.9% (95% CI, 38.6% to 69.3%) for the bivalent BA.4-5 vaccine and 57.9% (95% CI, 48.5% to 67.4%) for the BA.1 vaccine.CONCLUSIONS:
In immunocompromised individuals, vaccination with bivalent BA.4-5 or BA.1 booster lowered the risk of Covid-19-related hospitalization and death over a follow-up period of 9 months. The effectiveness was highest during the first months since vaccination with subsequent gradual waning.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Immunization, Secondary
/
Immunocompromised Host
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COVID-19 Vaccines
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SARS-CoV-2
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COVID-19
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Vaccine Efficacy
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Hospitalization
Limits:
Adult
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Aged
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Female
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Humans
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Male
/
Middle aged
Country/Region as subject:
Europa
Language:
En
Journal:
J Infect
Year:
2024
Document type:
Article
Country of publication:
United kingdom