Arexvy is a vaccine used to prevent lower respiratory tract disease caused by respiratory syncytial virus (RSV). It is FDA-approved for adults 60 and older, and for adults 18 through 59 who are at increased risk of severe RSV illness. Made by GSK, it was the first RSV vaccine approved for older adults and remains one of three RSV vaccines currently available in the United States.
Who Should Get Arexvy
The CDC recommends a single dose of RSV vaccine for all adults 75 and older, regardless of other health conditions. For adults between 50 and 74, the recommendation applies if you have an underlying condition that raises your risk of severe RSV disease. Those conditions include:
- Chronic heart disease such as heart failure or coronary artery disease (high blood pressure alone does not qualify)
- Chronic lung conditions like COPD, emphysema, asthma, or interstitial lung disease
- Kidney disease requiring dialysis or other replacement therapy
- Complicated diabetes that has caused kidney damage, nerve damage, or eye damage, or that requires insulin
- Neurologic or neuromuscular conditions that weaken respiratory muscles or impair the ability to clear the airway
- Chronic liver disease such as cirrhosis
- Severe obesity with a BMI of 40 or higher
- Moderate or severe immune compromise
- Residence in a nursing home
Your provider can also recommend the vaccine if other factors raise your risk, including frailty or living in a remote area where getting to a hospital quickly would be difficult.
How Well It Works
In a large phase 3 clinical trial spanning 17 countries, Arexvy reduced RSV-related lower respiratory tract disease by about 75%. For cases serious enough to need medical attention, efficacy was slightly higher at roughly 78%. These numbers represent protection over the first RSV season following vaccination.
Arexvy is given as a single, one-time dose. Unlike the flu shot, you do not get it every year. It is a 0.5 mL injection given in the upper arm muscle, similar to most other vaccines.
How the Vaccine Works
RSV uses a protein on its surface, called the F protein, to fuse with and enter your cells. This protein exists in two shapes: one before it attaches to a cell (the pre-fusion form) and one after. Arexvy contains a lab-made version of the pre-fusion form, which is the shape that triggers the strongest immune response. When your immune system encounters this protein through the vaccine, it produces neutralizing antibodies that can block the real virus from entering cells if you’re exposed later. The F protein is the main target of naturally occurring RSV-fighting antibodies in humans, making it an effective foundation for a vaccine.
Common Side Effects
Most side effects are mild to moderate and resolve within a few days. In the phase 3 clinical trial, the most frequently reported reactions were pain at the injection site (61%), fatigue (34%), muscle aches (29%), and headache (27%).
Real-world data from over 2,000 adults aged 60 and older in Australia painted a similar picture, though rates were somewhat lower than in the trial setting. About 37% of recipients reported any side effect at all. Injection-site pain was the most common local reaction at 26%, while fatigue (21%), muscle aches (13%), and headache (12%) were the most common whole-body symptoms. Fever occurred in about 5% of people. Fewer than half a percent needed to visit a healthcare provider because of a side effect.
A Rare but Serious Safety Signal
The FDA has added a warning to Arexvy’s prescribing information about a possible link to Guillain-Barré syndrome (GBS), a rare condition in which the immune system attacks the nerves, causing weakness and sometimes temporary paralysis. In the original clinical trials, one participant out of roughly 16,000 vaccinated developed GBS nine days after receiving the shot.
Post-approval monitoring using insurance claims data estimated about 7 extra cases of GBS per million doses administered to adults 65 and older during the 42 days after vaccination. The FDA has stated that while the evidence suggests an increased risk, it is not yet sufficient to confirm a direct cause-and-effect relationship. A larger study of 1.9 million vaccinated adults has been required to further evaluate this risk. For context, GBS is also a known rare complication of RSV infection itself and of several other vaccines.
How Arexvy Compares to Other RSV Vaccines
Arexvy is one of three RSV vaccines now licensed for adults in the United States. The other two are Pfizer’s Abrysvo and Moderna’s mResvia. All three target the same pre-fusion F protein and carry the same CDC recommendation for adults 75 and older or adults 50 to 74 with increased risk. The GBS warning applies to both Arexvy and Abrysvo. The choice between them typically comes down to availability and your provider’s recommendation rather than major differences in who they’re intended for.