RSV vaccine not just a shot in the dark

Which adults should get the RSV vaccine?

The “Health Matters” column in Legatus magazine’s February 2023 issue discussed respiratory syncytial virus (RSV), which can cause illnesses ranging from the common cold to inflamed bronchioles (bronchiolitis) to pneumonia. Since then, the U.S. Food and Drug Administration has approved two vaccines to prevent RSV disease in adults 60 years of age and older. What do we know about these vaccines, and who should get them?

Last May, the FDA approved GlaxoSmithKline’s Arexvy vaccine. That vaccine consists of an RSV protein called preF. An injection of that protein causes the body to make antibodies that neutralize the virus, thus inducing immunity against it. 

Arexvy also contains an “adjuvant” — a substance that boosts the body’s immune response. (The adjuvant in Arexvy is the same as that in GSK’s shingles vaccine, though at half the dose.) A placebo-controlled seven-month trial involving 24,966 adults 60 years of age and older found that a single dose of Arexvy reduced the overall risk of lower respiratory tract disease (including bronchiolitis and pneumonia) by 83 percent and of severe LRTD by 94 percent. Vaccine recipients reported sore arms for a few days as well as general symptoms like headache, fatigue, and muscle aches, but not more serious reactions.

Four weeks later, the FDA approved Pfizer’s Abrysvo vaccine. This vaccine contains two slightly different preF proteins but no adjuvant. A placebo-controlled seven-month trial in 32,284 adults 60 years of age found that a single dose of Abrysvo reduced the overall risk of LRTD by 67 percent and of severe cases by 86 percent. The vaccine also caused some arm pain — though not as frequently as the adjuvanted vaccine — but it did not cause more general symptoms than placebo. During this study, two serious events (Guillain-Barré syndrome and atrial fibrillation) happened somewhat more often in vaccine recipients than in placebo recipients, but the differences were not statistically significant.

Each year in the United States, RSV causes significant morbidity (60,000-120,000 hospitalizations) and mortality (6,000-10,000 deaths) among adults 65 years of age and older. Risk increases with age and is higher among frail, elderly persons and those with cardiopulmonary disease or immune compromise. In June, an advisory committee 
of the Centers for Disease Control and Prevention recommended RSV vaccination for people 60 years of age and older with “shared clinical decision making” — in consultation with one’s doctor over the potential risks and benefits. The committee shied away from recommending it for all older adults, given the high cost of the vaccine ($280-$295), the absence of highest-risk individuals in the clinical trials, and a lack of findings about RSV hospitalizations or deaths.

The bottom line: RSV can cause serious infections in adults. Talk with your doctor about how to prevent it.