A large new study from England shows that COVID-19 booster vaccines significantly reduced the risk of hospitalization and death, especially among adults aged 50 and older.
The research, led by scientists from the University of Bristol and the University of Oxford, analyzed data from more than three million people who received booster shots during the autumn 2022 vaccination campaign.
The findings were published in the journal Vaccine.
Previous research had already shown that the original COVID-19 vaccines were effective at preventing severe illness.
This new study focused specifically on the added protection provided by booster doses. Researchers compared outcomes in people who received a booster with those in similar individuals who did not.
Using health records from general practices and hospitals across England, the team matched 3,464,877 boosted adults with an equal number of unboosted adults who were similar in age, health status, previous vaccinations, and location.
Participants were followed for nearly a year to track COVID-19 hospitalizations and deaths.
The results showed clear benefits. People who received a booster had roughly half the risk of being hospitalized or dying from COVID-19 compared with those who did not receive an additional dose.
Over a 350-day period, hospitalization rates were about 3.78 per 1,000 people in the boosted group, compared with 6.81 per 1,000 in the unboosted group. Death rates were also lower, at 0.29 per 1,000 compared with 0.61 per 1,000.
The study also compared two commonly used booster vaccines: Moderna and Pfizer-BioNTech. Researchers found that both provided similar protection against severe COVID-19 outcomes.
However, the level of protection gradually declined over time, with the strongest effect seen in the first two to three months after vaccination.
In total, the researchers monitored more than 2.5 million people during the follow-up period and recorded over 14,000 COVID-19 hospitalizations and more than 1,100 COVID-19 deaths. They also tracked non-COVID-related deaths and fractures to check whether other factors might influence the results.
Interestingly, boosted individuals had a slightly lower risk of fractures, which are unrelated to COVID-19. Researchers believe this may reflect differences in health or behavior between people who choose vaccination and those who do not.
However, the effect was much smaller than the reduction in COVID-19 risks, suggesting the main findings are reliable.
Lead researcher Dr. Paul Madley-Dowd emphasized that the results reinforce the importance of booster vaccination for older adults, who face the highest risk from COVID-19. He noted that booster doses continue to play a crucial role in preventing severe illness and saving lives.
The study adds to growing evidence that staying up to date with COVID-19 vaccinations provides meaningful protection, even as the virus continues to evolve.
Health experts say booster programs remain an important tool for reducing strain on hospitals and protecting vulnerable populations, particularly during waves of infection.
Overall, the findings highlight that booster shots can make a significant difference in reducing the most serious consequences of COVID-19 among older adults.
