One of the first studies to test the new bivalent Covid-19 booster vaccine shows it to be highly effective in reducing deaths and hospitalizations
Since September 2022, bivalent mRNA vaccines, containing elements of the original wild-type COVID strain and an updated component of the Omicron strain, have replaced the older-style monovalent boosters in the US, Israel and other countries. These vaccines were designed to help enhance vaccine-induced immunity against the omicron variant and subsequent subvariants.
A new study published in The Lancet Infectious Diseases and presented at the European Congress of Clinical Microbiology and Infectious Diseases (ECCMID 2023, Copenhagen April 15-18) is one of the first to assess the effectiveness of this new type of COVID-19 vaccine in vulnerable people. people aged 65 and over. The study evaluated Pfizer’s bivalent vaccine, as Pfizer is the main supplier of COVID vaccines to Israel.
The study shows that, compared to people in this age group eligible for this bivalent booster but not receiving itwho received it had a 72% lower risk of COVID-19-related hospitalization and a 68% lower risk of COVID-19-related death.
“Bivalent mRNA booster vaccination in adults 65 years and older is an effective and essential tool to reduce the risk of hospitalization and death from COVID-19. Vaccination remains the main tool to avoid severe COVID-19,” explains study co-author Dr. Ronen Arbel, Division of Community Health Services, Clalit Health Services, Tel Aviv, and Maximization Research Laboratory. of Health Outcomes, Sapir College, Sderot, Israel. “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 greater protection against severe outcomes.”
To date, no randomized controlled trials are available evaluating the clinical efficacy of a bivalent mRNA booster vaccine. Bivalent mRNA booster vaccines are currently a priority in Israel for people at high risk of severe COVID-19, primarily those 65 years of age or older. This enabled the authors to conduct a retrospective cohort study to assess the efficacy of a booster dose of the bivalent mRNA vaccine in preventing hospitalizations and deaths from COVID-19.
Between September 27, 2022 and January 25, 2023, 569,519 eligible participants were identified. Of these, 134,215 (24%) participants received a bivalent mRNA booster vaccine during the study period. Hospitalization due to COVID-19 occurred in 32 participants who received a bivalent mRNA booster and 541 who did not receive a bivalent booster (with analysis showing this means a 72% reduction in hospitalization risk for those who receive the bivalent booster).