An RSV prevention drug wasn’t received by most infants, CHOP study found

New research from the Children’s Hospital of Philadelphia shows the challenges of getting families to accept a promising new drug that protects against RSV, a common cold-like virus that can cause severe illness and hospitalization in infants.

The drug, Beyfortus, was the first preventive medication against RSV for otherwise healthy infants. Many doctors applauded its FDA approval in 2023 as an opportunity to guard against the highly contagious virus, which had overwhelmed children’s hospitals in an unusual “tripledemic” of respiratory illnesses the previous winter.

But only 35% of children eligible for Beyfortus received it in the first season after rollout, according to the new study that looked at data from the CHOP Primary Care Network’s 32 practices across Pennsylvania and New Jersey.

The researchers found that uptake was lowest among patients who were publicly insured, Black, or lived in socioeconomically disadvantaged neighborhoods. The study was published Thursday in Pediatrics, the medical journal of the American Academy of Pediatrics, and had a sample size of 7,208 patients.

“In order to see the full benefit of this, we really need all of these young infants to consistently receive the treatment. And unfortunately, we haven’t gotten the numbers there yet,” said Ericka Hayes, who serves as senior medical director of infection prevention and control at CHOP and was not involved in the study.

RSV, short for respiratory syncytial virus, usually causes mild symptoms like a runny nose and cough. However, it can be dangerous, especially for infants.

“Their airways are so small that when they get inflamed, it starts to make it hard for them to breathe,” said Jeffrey Gerber, a pediatric infectious disease doctor at CHOP and senior author of the study.

In children younger than 12 months, the virus can quickly escalate into severe respiratory illness and pneumonia, requiring hospitalization. There’s no treatment for the virus. Doctors can try to manage the symptoms by supplying oxygen, giving IV fluids, and in some cases using a mechanical ventilator.

In the U.S., hundreds of children die from RSV every year, and tens of thousands are hospitalized with severe illness, according to the Centers for Disease Control and Prevention.

Beyfortus has been shown to decrease the likelihood of hospitalization by 80%.

It isn’t technically a vaccine, Gerber said.

The drug is what’s called a monoclonal antibody, a type of protein that binds to a specific target. The immune system normally makes antibodies as part of its defense against bacteria and viruses.

You can think of antibodies as police officers patrolling our body for a specific criminal. Once that target is identified, the antibody “handcuffs” the perp by binding to it. Then it marks it for destruction and removal from the body.

Beyfortus stops the RSV virus from invading cells and causing disease.

Taking it means your body is armed with antibodies, ready to defend against RSV. Normally, the body would not make such antibodies until after it had been exposed to the virus.

The treatment is given as a single injection to infants under 8 months of age. It’s only meant to last through the RSV season in the fall and winter months. After five to six months, the antibodies start to break down and the drug’s protective effect is gone.

“It’s a way to just buy time, get them through a season,” Gerber said.

By the next year, the child would be bigger and “more ready to take on RSV,” he added.

The CDC recommends that otherwise healthy infants under eight months of age get Beyfortus between October and March. If a baby is born between October and March, they should get it at birth or within their first week of life. If born outside that window, children can get it during any visit to the doctor.

The best timing would be shortly before the seasonal wave of RSV illness begins, between October and November.

Most families should not have to pay costs if they have insurance. Even if you’re uninsured or underinsured, the drug is covered at no cost for eligible children through the federal government’s Vaccines for Children program.

Another option is for pregnant individuals to get the maternal RSV vaccine, Abrysvo, between 32 and 36 weeks of pregnancy during September through January.

Gerber, the senior study author, didn’t find it surprising that only a third of children received the drug.

After all, the drug was new, and it was only its first season being available.

In its second season, uptake doubled to two-thirds of eligible children receiving it, according to more recent, still unpublished data from the team at CHOP, Gerber said.

Still, the racial and socio-economic disparities in who received it are striking and speak to possible misinformation and hesitancy surrounding new therapies, said Hayes, the medical director of infection prevention and control at CHOP.

Hayes encourages families to talk with their primary care provider to make well-informed decisions.

“Having seen how horribly sick these children get, we would really encourage parents to take advantage of this opportunity to avoid unnecessary suffering,” she said.

Hayes recalled caring for a “perfectly healthy” 4-month-old child who, in the span of three days, went from laughing, playing, and being fed at home to being in an intensive care unit with a tube down their throat.

“We always wished that we had some sort of treatment to help prevent this,” Hayes said.