Respiratory syncytial virus, or RSV, is commonly thought of as a childhood infection. But it also causes serious illness in older adults. In later life, an infection that begins like a cold can progress to inflammation in the lungs, pneumonia or a worsening of existing heart or lung disease.
Vaccines introduced in 2023 and 2024 give eligible older adults a way to reduce the risk of severe RSV disease. They do not prevent every infection, and they are not recommended for everyone in the same way. The key is understanding what the evidence shows—and what it does not.
Why RSV matters in later life
RSV can cause a runny nose, cough, fever and fatigue. Many people recover without special treatment. But the risk of severe illness rises with age and with some chronic conditions, including heart and lung disease. A bout of RSV can also put extra strain on a person whose health is already fragile.
That makes RSV more than a seasonal nuisance for some older people. In the United States, the Centers for Disease Control and Prevention estimates that RSV leads to tens of thousands of hospitalizations among adults aged 65 and older each year. The exact burden varies from season to season, and estimates made before vaccines became available do not tell us precisely how many illnesses vaccination will prevent.
What the vaccine studies found
The first RSV vaccines for older adults were tested in large clinical trials. In one trial of adults aged 60 and older, the GSK vaccine reduced the risk of RSV lower respiratory tract disease by about 83% during the first season after vaccination. That result describes protection against a defined illness outcome in a trial; it does not mean that 83% of all RSV infections are prevented, or that protection is identical for every person.
Other vaccines have also been authorized for older adults. The products differ, and their trial results should not be treated as though they came from one direct, head-to-head comparison. Studies and ongoing monitoring continue to examine how well protection holds up over time and across different groups of people.
One practical point is already clear: in the United States, CDC guidance calls for a single dose for adults who meet its current age and risk criteria—not a routine dose every year. The precise eligibility guidance can change as evidence develops, so older adults should check the current CDC recommendations or ask a clinician or pharmacist. RSV seasons also differ around the world; timing that makes sense in one country may not fit another.
Protection is not the same as a guarantee
A vaccine lowers risk; it cannot promise that a vaccinated person will not catch RSV or become seriously ill. Protection can vary with age, health and time since vaccination. Older adults can still benefit from practical steps such as staying home when ill, improving ventilation where feasible, washing hands and avoiding close contact with people who have respiratory symptoms.
Vaccination decisions are especially worth discussing for people with chronic heart or lung conditions, weakened immune systems or other factors that may raise their risk. A health professional can help weigh a person’s circumstances against the expected benefit and any relevant precautions. Someone who has had a serious reaction to a vaccine should mention it before getting another.
What to know about side effects
Common reactions reported after RSV vaccination include a sore arm, tiredness, headache and muscle aches. These effects are usually temporary. As with other vaccines, safety monitoring continues after a product is authorized, because very rare problems may not show up clearly in trials.
Regulators have also been monitoring a possible link between some RSV vaccines and Guillain-Barré syndrome, a rare neurological condition. A safety signal does not mean that the vaccine causes the condition in every case, but it is part of the information clinicians consider. People can ask about the latest safety evidence and how it applies to their health.
A useful addition to prevention
RSV vaccines are a significant new option for reducing the chance of severe illness among eligible older adults. Their value is clearest when the promise is stated accurately: they can lower risk, but they do not remove it, and guidance is based on age, health and evolving evidence.
For an older adult deciding whether to get vaccinated, a useful conversation is specific: Am I eligible under current local guidance? When is the right time where I live? What benefits and risks matter most given my health history? Those questions turn a new medical tool into a more informed personal choice.
