FDA Approves First-Ever RSV Vaccine

After Houston-area hospitals saw one of the worst spikes of RSV hospitalizations this winter, medical professionals are looking forward to the anticipated relief that a string of vaccines will provide to those that are at risk of contracting this respiratory virus.

The first Arexvy made by GSK, was approved by the Food and Drug Administration this week and is pending recommendation by the Centers for Disease Control and Prevention’s advisory committee on immunization practices which will meet next month.

Dr. Peter Hotez, co-director of the Texas Children’s Hospital Center for Vaccine Development and dean of the National School of Tropical Medicine at Baylor College of Medicine, said the CDC usually is in line with the FDA, meaning this vaccine could be greenlighted and available as early as this fall.

Arexvy will be a single-shot immunization only available to those that are 60 years or older.

According to Hotez, it is likely that eventually it will also be given to those who are immunocompromised – whether they have a pre-existing lung, heart or other underlying health condition.

These are the two adult populations that are most affected by severe cases of this disease. Infants and younger children also are at a higher rate of contracting life-threatening symptoms form the virus, but they are not eligible to receive this vaccine, he said.

Most who have RSV tend to have a cough and other cold-like symptoms that they are able to get over within a two-week period, but for these populations, this disease could lead to hospitalizations or even death, Hotez said.

There are two other RSV vaccines that are expected to follow Arexvy – both Pfizer-made immunizations – one of which is only administered to mothers who are pregnant to provide protection to their babies once they are born.

“The idea behind this is you immunize women possibly in the third trimester of pregnancy to give them antibodies that will be transferred to the baby so that when the baby is born, it will have protection against RSV in infancy,” Hotez said.

Children who are this early in age are more likely to be unresponsive to vaccinations, so Hotez said this immunization would be more effective to prevent severe infection in these younger cases.

So far, Arexvy is the only RSV vaccine that has received FDA approval – and is the first to do so after years of development. There are also several others alongside the two Pfizer immunizations, that are still in clinical trails or prepping to submit to the FDA for approval, he said.

In clinical trials where the immunization was tested on about 25,000 older adults, GSK reported that the vaccine was 83 percent effective in preventing lower respiratory tract disease and 94 percent effective in preventing severe disease in these seniors and those who were immunocompromised.

Two of the only routine symptoms of those who received the immunization included tenderness at the sight of injection and fatigue, however both wore off in a matter of days.

Hotez expects Arexvy to be longer-lasting in protection as it is a recombinant protein vaccine – one that uses a fusion protein from the actual virus to block entry of the virus and any further replication. These vaccines are typically more durable when compared to mRNA-based vaccines.

According to Hotez, he expects this vaccine to provide immunity against RSV for at least several months to a year as this virus is not like COVID-19 or the flu. These two diseases constantly change over time, whereas RSV does shift in composition just not as often as the others.

“The nice thing about RSV is you tend not to see the kind of variation in the antigenic makeup that you see in influenza every year and nothing like we’ve seen with the transition from Delta to Omicron or the various other kinds of COVID-19,” Hotez said.

Despite several other non-RSV related vaccines – like the new bivalent booster – being made available or pending the final stages of approval for distribution to these older populations, Hotez is concerned about the number of patients that will actually be willing to receive them.

“We’re seeing this kind of transformation or revolution in adult immunizations to help seniors live longer and healthier lives, but the important question is will we have the health systems to keep up with it all and educate the adults,” Hotez said. “Right now, the percentage of adults who are agreeing to get vaccinated is not quite as high as we would like.”

Hotez said this is especially the case for vaccinations related to COVID-19, as the CDC reported with the first bivalent booster, only 17 percent of those eligible across the country actually received it.

He said there is going to be a fair amount of education that needs to be provided to the patients receiving Arexvy and to the medical officials administering it prior to its distribution.

“Unfortunately, we have a pretty active anti-vaccine movement that seems to be drawing a line in the sand against the introduction of new vaccines, so that’s going to be something we have to contend with as well.”