The bivalent mRNA COVID-19 vaccine is effective in reducing the risk of hospitalisation or death among older people, according to one of the first studies to assess the vaccine.
A new Israeli study, published today in The Lancet Infectious Diseases and presented at the European Congress of Clinical Microbiology & Infectious Diseases in Copenhagen, Denmark, assessed the Pfizer bivalent vaccine, which is the main supplier of COVID vaccines to Israel.
It found individuals aged 65 and over who had the bivalent booster vaccine had a 72% lower risk of hospitalisation because of COVID-19 and a 68% lower risk of COVID-19 related death compared to those who did not receive it.
Study author Dr Ronen Arbel, from Clalit Health Services, Tel Aviv, said: “Bivalent mRNA booster vaccination in adults aged 65 years or older is an effective and essential tool to reduce their risk of hospitalisation and death due to COVID-19. Vaccination remains the primary tool for avoiding severe COVID-19.
“Our findings highlight the importance of new types of vaccines containing different variants of SARS-CoV-2, which are likely to induce broader immune responses and provide enhanced protection against severe outcomes.”
Between 27 September 2022, and 25 January 2023, 569,519 eligible participants were identified, of whom 134,215 (24%) received a bivalent mRNA booster vaccination during the study period.
Among the cohort, 32 who received a bivalent mRNA booster vaccination were hospitalised due to COVID-19 compared to 541 who did not receive a bivalent booster vaccination.
The researchers say the adjusted risk for COVID-19 hospitalisations in the bivalent mRNA booster recipients was 0.035% versus 0.124% in the non-recipients.
The adjusted risk for COVID-19 death was 0.013% in the bivalent mRNA booster recipients versus 0.040% in the non-recipients, meaning a 68% relative risk reduction death for the bivalent vaccine recipients.
Although the research team noted a number of limitations with its study, they conclude: “Our results suggest that the bivalent mRNA vaccine booster dose is associated with a reduced risk of severe COVID-19 outcomes in adults aged 65 years or older. Our findings highlight the importance of bivalent booster vaccination in populations at high risk of severe COVID-19 and the necessity to increase efforts to encourage eligible people to be vaccinated.”
Effectiveness of a bivalent mRNA vaccine booster dose to prevent severe COVID-19 outcomes: a retrospective cohort study. Lancet Infectious Diseases 14 April 2023.
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