Elderly woman receiving the RSV vaccine from a doctor.

September 20, 2023

Two respiratory syncytial virus (RSV) vaccines for older adults and an RSV monoclonal antibody preventive therapy for infants and young children are now available to the public.

The vaccines are available at most major U.S. pharmacies.

The U.S. Food and Drug Administration (FDA) has approved an RSV monoclonal antibody for infants and young children. The monoclonal antibody acts similarly to a vaccine:

FDA approved two RSV vaccines for adults 60+ years of age:

Beyfortus (nirsevimab-alip) is intended to help protect newborns and infants during or entering their first RSV season; and children up to 2 years of age who are entering their second RSV season at high risk for severe RSV.

Arexvy and Abrysvo are intended to help protect older adults, particularly those with asthma and COPD who are at high risk for severe RSV.

In addition, Abrysvo can be given during pregnancy to prevent RSV in newborns and infants. It is approved for use at 32 through 36 weeks gestational age of pregnancy.

When administered, the RSV treatments develop antibodies against the protein that enters cells and causes the virus.  The Arexvy vaccine also includes an adjuvant. An adjuvant helps boost the immune system and increases the effect of the vaccine.

What is RSV? It’s a common respiratory virus, especially in children. It can cause fever, coughing, wheezing, runny nose and decreased appetite. RSV is very contagious. By the time children are 2 or 3 years old, most have had it at least once.

RSV is common in adults, too. For many patients, symptoms are treatable. But for some, symptoms may turn severe and require hospitalization. Severe symptoms include fever, severe cough and wheeze, rapid breathing and/or difficulty breathing.

Research into RSV’s impact on adults ages 65 and older has found that:

  • RSV causes approximately 60,000-120,000 hospitalizations each year
  • RSV causes 6,000-10,000 deaths each year

More RSV vaccines are in the pipeline. AstraZeneca and Sanofi are the makers of Beyfortus. GSK is the manufacturer for Arexvy. Pfizer makes Abrysvo. Moderna’s RSV vaccine is in clinical trials.

RSV vaccines are also coming soon for adults 18-60 who have an underlying medical condition such as asthma.

Beyfortus underwent three clinical trials that showed it reduced risk of severe RSV infection by 75% in infants and children ages 2 and younger. For children born prematurely, which makes them more susceptible to severe illness, it reduced the risk of severe RSV by 70%.

Arexvy clinical trials involved 25,000 adults 60+ years of age. The vaccine showed the following:

  • 82.6% effectiveness against lower respiratory tract disease (LRTD) caused by RSV;
  • 94.1% effectiveness against severe cases of LRTD caused by RSV;
  • 94.6% effectiveness in adults with at least one underlying medical condition.

GSK states that the Arexvy vaccine “will be available for older adults before the 2023/24 RSV season.” The RSV season starts in the fall and usually lasts until spring.

Abrysvo clinical trials involved 37,000 adults 60+ years old. The vaccine was 66.7% effective against RSV defined by two or more symptoms. It was 85.7% effective against more severe RSV illness, defined by three or more symptoms.

A separate clinical trial of 3,500 people evaluated Abrysvo during pregnancy. When given to pregnant individuals, Abrysvo reduced the risk of severe LRTD by 81.8% within 90 days after birth. Within 180 days after birth, it reduced the risk of severe LRTD by 69.4%.

Side effects from the RSV vaccines included pain, redness and swelling where the shot is given, fatigue, fever, headache, nausea, diarrhea, and muscle or joint pain. These side effects were usually mild.

How long do the vaccines offer protection against RSV? Clinical trials of each vaccine indicate that protection should last an entire RSV season, which is about five months. It could potentially last up to a year.

Reviewed by:
Purvi Parikh, MD, FACAAI
is an adult and pediatric allergist and immunologist at Allergy and Asthma Associates of Murray Hill in New York City. She is on faculty as Clinical Assistant Professor in both departments of Medicine and Pediatrics at New York University School of Medicine.