Effectiveness of homologous/heterologous booster COVID-19 vaccination schedules against severe illness in general population and clinical subgroups in three European countries

Vaccine. 2023 Oct 17:S0264-410X(23)01181-7. doi: 10.1016/j.vaccine.2023.10.011. Online ahead of print.ABSTRACTUsing 4 data-sources (Spain, Italy, United Kingdom) data and a 1:1 matched cohort study, we aimed to estimate vaccine effectiveness (VE) in preventing SARS-CoV-2 infections with hospitalisations (±30 days) and death (±56 days) in general population and clinical subgroups with homologous/heterologous booster schedules (Comirnaty-BNT and Spikevax-MOD original COVID-19 vaccines) by comparison with unboosted individuals, during Delta and beginning of Omicron variants. Hazard Ratio (HR, by Cox models) and VE ([1-HR]*100) were calculated by inverse probability weights. Between December 2020-February 2022, in adults without prior SARS-CoV-2 infection, we matched 5.5 million people (>1 million with immunodeficiency, 343,727 with cancer) with a booster (3rd) dose by considering doses 1 and 2 vaccine brands and calendar time, age, sex, region, and comorbidities (immunodeficiency, cancer, severe renal disease, transplant recipient, Down Syndrome). We studied booster doses of BNT and MOD administered after doses 1 and 2 with BNT, MOD, or Oxford-AstraZeneca during a median follow-up between 9 and 16 weeks. BNT or MOD showed VE ranging from 70 to 86% across data sources as heterologous 3rd doses, whereas it was 42-88% as homologous 3rd doses. Depending on the severity and available follow-up, 3rd-dose effectiveness lasted between 1 and 5 months. In people with immunodeficiency...
Source: Vaccine - Category: Allergy & Immunology Authors: Source Type: research