TL;DR: Yes! The new bivalent booster vaccine does give additional protection against symptomatic COVID-19 infections, reduces emergency department and urgent care visits, and reduces the risk of hospitalization.
In September 2022, the US Advisory Committee on Immunization Practices (ACIP) recommended that all persons aged 12 and up who had already gotten their primary series of COVID-19 vaccines get the new and improved bivalent COVID-19 booster vaccine. This vaccine contains components of both the original strain of SARS-CoV-2 and the Omicron BA.4/BA.5 strains. The recommendation was expanded in October to include kids aged 5 and up.
The recommendations were based on immunogenicity data (looking at antibodies after getting a vaccine). While this is helpful data to know, it does not always translate into meaningful clinical outcomes. The next step is to measure if the vaccine prevented real world stuff that people care about, like “am I less likely to get sick if I get this vaccine?” or “am I less likely to need to go to the hospital if I get sick?”
The CDC has published a few new studies to help answer these questions! They found that:
The relative vaccine effectiveness (rVE) of the bivalent booster compared with at least 2 doses of the monovalent vaccine 2-3 months after the last monovalent dose was 30% for ages 18-49 years, 31% for ages 50-64 and 28% for 65 years and up. This means that the bivalent booster adds protection against getting sick compared to just getting the monovalent vaccines!
The vaccine effectiveness (VE) of a bivalent booster dose (after 2, 3, or 4 monovalent doses) against having to go the emergency department or urgent care for COVID-19–associated illness was 56% compared with no vaccination, 31% compared with receipt of last monovalent dose 2–4 months earlier, and 50% compared with receipt of last monovalent dose 11 or more months earlier.
For adults who are immunocompetent (they don’t have immune suppressing illnesses or medications) and 65 years old or older, the bivalent booster provided 73% additional protection against COVID-19 hospitalization compared with past monovalent mRNA vaccination only.
The bivalent boosters were helpful at restoring protection after immune waning. We know this because the vaccine effectiveness increased with longer time since the last monovalent dose.
Bivalent boosters added protection when Omicron BA.4/BA.5 strains were the predominant circulating strains. This is important: we know that the original monovalent vaccine efficacy went down with these strains.
Only about 14% of eligible people in the US have received the bivalent COVID-19 booster. These studies highlight how important it is to get boosted! As COVID-19, flu, and RSV are on the rise and the tripledemic is kicking our healthcare system’s collective butts, getting boosted is more important than ever.
Stay safe. Stay well. Get boosted!
Those Nerdy Girls
CDC MMWR Effectives of Bivalent mRNA Vaccines in Preventing Symptomatic SARS-CoV-2 Infection
CDC MMWR Early Estimates of Bivalent mRNA Vaccine Effectiveness in Preventing COVID-19 Associated Emergency Department or Urgent Care Encounters
CDC MMWR Early Estimates of Bivalent mRNA Vaccine Effectiveness in Preventing COVID-19–Associated Hospitalization Among Immunocompetent Adults Aged ≥65 Years