In the 2023-2024 season, adults 60 and older who got GSK’s RSV vaccine (Arexvy) had about 83% lower risk of landing in the hospital with RSV, and those who got Pfizer’s (Abrysvo) had about 73% lower risk, according to real-world effectiveness data summarized by the CDC.
The CDC recommends a single RSV shot for all adults 75 and older, and for adults 50 to 74 at increased risk of severe RSV, such as people with heart failure, coronary artery disease, COPD, asthma, or kidney failure on dialysis. If you fall in one of those groups and have never had the shot, this study is a good reason to ask your doctor or pharmacist about it now. The CDC says the shot does the most good in late summer or early fall, which for most of the country means August through October.
If you already had one, the CDC says you are done for now. It is not a yearly shot.
Key takeaways
- In adults 60 and older during the 2023-2024 season, Arexvy was about 83% effective and Abrysvo about 73% effective against RSV hospital stays.
- Both brands also showed protection in adults 60 and older with certain conditions that weaken the immune system.
- This covers one season only, so it says little about how long protection lasts.
What the study found
The 2023-2024 season was the first RSV season after the two vaccines were approved.
Compared with unvaccinated seniors, the study reports:
- By brand, against hospital stays: about 83% for Arexvy and 73% for Abrysvo. In plain terms, Arexvy cut the risk of an RSV hospital stay by about 83%, and Abrysvo by about 73%.
- Weakened immune systems: both brands also showed protection in adults 60 and older with certain immunocompromising conditions.
Effectiveness did not change significantly with age.
Dr. Kumar’s take
These are strong numbers, and they come from a huge real-world population rather than a small trial. The headline leaves a few things out.
This is one season. The study covers only the first winter after the shot, not year two or three. That matters more than usual here, because the RSV vaccine is currently given once, not every year. The CDC says the need for more doses will be evaluated in the future. Whether one shot keeps protecting you over several winters is the open question.
The people who got vaccinated were different. The authors note that vaccinated seniors were less likely to have low income, lived in more affluent areas, and were more likely to have had flu and COVID shots. People like that tend to be healthier and see doctors more.
The brand gap is not a contest. Arexvy came in at 83% and Abrysvo at 73%. This was not a head-to-head trial, and the two groups were only compared against unvaccinated people. A 10-point gap in data like this is not a reason to hold out for one brand. Both worked well.
Safety is a separate question. This study measured protection, not side effects. People ask about Guillain-Barré syndrome, a rare nerve disorder. The CDC points to updated safety analyses from the FDA and Medicare that check Guillain-Barré diagnoses against medical charts. That rare risk has to be weighed against a virus that sends many older adults to the hospital, and this study shows how much of that the shot prevents.
With mixed messages about fall vaccines, many of the people most likely to benefit still have not had it. Vaccines that work this well can shift outcomes across a whole population, as the HPV vaccine did for cervical cancer deaths in England.
What it means for you
- 75 or older, never vaccinated: the CDC recommends one dose. Ask your doctor or pharmacist before RSV season starts.
- 50 to 74 with heart disease, lung disease, kidney failure, or another higher-risk condition: the CDC recommends one dose for you too. Your doctor can tell you whether your conditions qualify.
- Already had the shot: the CDC does not recommend another dose at this time.
- Worried about side effects, including Guillain-Barré: bring that up with your doctor, who knows your history.
The finding supports getting the shot if you are in a recommended group. It does not show that a second dose helps, and it does not settle which brand is better.