Annual COVID-19 boosters continue to provide meaningful protection, study says
Even among people with residual immune protection from past infections, vaccinations, or both, updated COVID-19 boosters provided additional protection against hospitalisation.
- 23 June 2026
- 3 min read
- by Linda Geddes
At a glance
- Adults who received the 2025–2026 COVID-19 vaccine were around 55% less likely to be hospitalised with COVID-related disease and 50% less likely to require emergency or urgent care than those who did not receive it.
- Because many participants were likely to have had residual protection from previous infections, earlier vaccinations, or both, the results likely reflect the vaccine’s added benefit on top of this existing immunity.
- The study suggests updated boosters can still provide meaningful additional protection against COVID-19, particularly for people at higher risk of severe illness.
As the COVID-19 pandemic recedes further into many people’s memories, health authorities face an important question: do COVID-19 booster vaccinations still provide meaningful benefits in populations that have been repeatedly vaccinated, infected, or both?
The study helps address a question many countries face as COVID-19 continues to circulate: whether annual booster campaigns continue to provide meaningful protection against severe disease.
A new study suggests they do. Researchers found that the 2025-26 COVID-19 vaccine formulation reduced the risk of COVID-related hospitalisation by 55% and emergency department or urgent care visits by 50%, even though many participants were likely to have had some pre-existing immunity.
The findings suggest annual boosters still provide an important added layer of protection, particularly for people at high risk of severe COVID-19.
Are COVID-19 boosters worth it?
Health authorities routinely monitor vaccine effectiveness to determine how well existing or updated formulations perform in real-world settings. This data helps to inform decisions about vaccination recommendations, including the utility of seasonal booster campaigns.
In May 2025, the US Food and Drug Administration recommended that vaccine manufacturers update their COVID-19 vaccines to target the JN.1 family of variants, whose descendants continue to circulate widely today. Updated vaccines became available later that year.
Have you read?
To investigate how well these reformulated vaccines were performing, Dr Ryan Wiegand at the Centers for Disease Control and Prevention in Atlanta, US, and colleagues analysed data from more than 110,000 emergency department visits and hospital admissions among adults with COVID-19-like illness across seven US states between September and December 2025.
The research, published in JAMA Network Open, found that adults who received the 2025–2026 vaccine were around 55% less likely to be hospitalised with COVID-19 and 50% less likely to require emergency or urgent care than those who had not received the updated vaccine.
“The findings demonstrate the added benefit of 2025–2026 COVID-19 vaccination irrespective of protection conferred by previous COVID-19 vaccination or SARS-CoV-2 infection,” the researchers said.
What do these findings mean for ongoing COVID-19 vaccination programmes?
The study helps address a question many countries face as COVID-19 continues to circulate: whether annual booster campaigns continue to provide meaningful protection against severe disease.
The authors said the findings were particularly relevant because SARS-CoV-2 circulation increased shortly before the updated vaccines became available, meaning many of those in the study may have acquired additional immunity through recent infection.
“Vaccine effectiveness should therefore be interpreted as the added benefit of 2025–2026 COVID-19 vaccination in a population with high levels of infection-induced immunity, vaccine-induced immunity, or both,” they wrote.
