For the first time, families will have a long acting option to protect infants and high risk toddlers from a common respiratory virus that sends tens of thousands of children to the hospital every year.

The highly contagious seasonal respiratory syncytial virus, or RSV, usually causes mild, cold-like symptoms, but it may also lead to severe sickness for certain populations, particularly babies or children with lung diseases or weakened immune systems.

SEE ALSO: RSV: What parents should know

A recently approved AstraZeneca drug, called Nirsevimab or Beyfortus, is designed to protect infants through their first RSV season.

But because it’s currently in short supply, the Centers for Disease Control and Prevention recommends prioritizing available doses for infants at the highest risk for severe RSV disease this season.

A separate RSV vaccine is also being offered to pregnant people who can pass protection to newborns through their first six months of life.

Jill Lancaster, M.D., a pediatrician at University of Michigan Health C.S. Mott Children’s Hospital, answers parents’ top questions as they consider the new immunizations that can reduce the risk of RSV-related complications and hospitalizations.

Routine, but currently prioritized for high risk infants

Beyfortus will be part of recommended routine care for infants under eight months old just like other scheduled vaccinations and preventative care.

But because of high demand during its introductory season, the 100 milligram dose approved for children over 11 pounds is in very limited supply. As of mid November, 2023, there was also a shortage reported for the 50 mg dose for infants under 11 pounds.

Due to the 2023-2024 shortage, healthcare providers will prioritize available injections for those who are at the highest risk of severe RSV, including infants who are younger than six months old and other groups identified as high risk by the CDC.

Parents of children who have underlying health conditions but can’t get the new shot because of the shortage may talk to their doctor about whether a different medication, Synagis, could be an option.

Synagis, a monoclonal antibody, isn’t new but also prevents severe disease caused by RSV. However, it must be ordered by a doctor and taken monthly to be effective throughout the season.                    

Lancaster encourages families to talk to their child’s doctor about their options for RSV immunization.

“Moving forward, RSV protection will be offered along with routine vaccinations in a child’s first year,” Lancaster said.

“Including this shot during regularly scheduled well child visits ensures children get protection at the most opportune time and also allows families the chance to ask questions and discuss RSV with their child’s primary provider.”

Studies prove safety, efficacy of RSV drug for babies 

The United States Food and Drug Administration approved Beyfortus for babies and preterm infants born during or entering their first RSV season, and for children up to two years of age who remain vulnerable to severe RSV disease through their second RSV season.  

Unlike a vaccine that teaches the immune system to produce antibodies against a specific disease, this single dose injectable RSV drug delivers a dose of monoclonal antibodies directly to the bloodstream.

RSV is the leading cause of hospitalizations for infants. For infants whose immune systems are still developing, this temporary immunity offers powerful protection.” Jill Lancaster, M.D.

It can be administered at the beginning of the RSV season or during a regular follow up appointment.

Some newborns may also be able to get it at birth before they leave the hospital.

The drug’s years-long development spans three late-stage clinical trials demonstrating the shot is significantly effective in preventing moderate disease, hospitalization and the need for critical care through five months.

There is currently no medication to cure RSV and those hospitalized are supported with hydration and oxygen.

“RSV is the leading cause of hospitalizations for infants,” Lancaster said. “Trials show that this preventative medicine can protect newborns and babies through the duration of a typical RSV season.”

“For infants whose immune systems are still developing, this temporary immunity offers powerful protection. It can have a major impact for babies who may otherwise have been hospitalized or required ventilators.”

Side effects are mild and temporary

The most common side effects include swelling and pain at the injection site, which may cause irritability in infants.

No serious side effects have been identified in large studies.

“It’s important for families to understand that these medications undergo rigorous testing for safety and effectiveness before they are approved for use. Still, there will be continued careful monitoring as RSV protection is offered to broader populations,” Lancaster said.

“Any side effects associated with getting the shot are generally very low compared to the risks of contracting and suffering from the condition itself,” she added.

RSV is usually mild but can be severe in young children

RSV often leads to cold-like symptoms like coughing, a runny or stuffy nose, and a fever. Most children with RSV can rest and recover at home, Lancaster says.

However, some cases may become more serious.

Every winter, the CDC reports 58,000 to 80,000 RSV related hospitalizations among children younger than five and 100 to 300 deaths.

“Up to 2/3 of babies get RSV in their first year of life. For many of them, symptoms are minor but for some children, particularly infants, it may result in bronchiolitis or serious breathing difficulties,” Lancaster said.

“We know RSV can be serious for high risk babies, but we also see otherwise healthy children who develop severe symptoms,” she added.

“We can’t always predict who will require hospitalization, which is why the safer option is to get them protected.”

Parents should seek immediate medical attention, she says, if they notice young children having trouble breathing or see that their breathing that looks fast, labored or wheezy, or if their baby isn’t feeding well or having regular wet diapers.

Protection for pregnant people and their newborns

The FDA has also approved the first vaccine for pregnant people to protect them and their babies from RSV for half a year – an alternative option to babies getting a preventative shot after birth.

Pfizer’s single dose shot, Abrysvo, prompts the production of protective antibodies that a pregnant person may pass to their newborn through the placenta.

It’s approved for use in pregnant people in their third trimester between weeks 32 and 36 of pregnancy and would likely be offered during regular prenatal care appointments.

In the vaccine’s clinical trial, Abrysvo was found to lower the risk of severe disease from RSV among infants by 82% within roughly three months after birth.

By around six months, the efficacy was around 69%.

“Physicians should inform pregnant patients about supply concerns and discuss options for them to receive the RSV vaccine during pregnancy to protect newborns immediately after birth and throughout the RSV season,” Lancaster said.

Reducing strain of seasonal viruses on children’s hospitals

RSV has overwhelmed hospitals over recent fall and winter seasons, particularly in 2022 when the combination of flu, COVID-19 and significant RSV surges caused what some experts called a “tripledemic.”

“I think everyone is still very concerned the season could be similar to previous years with the triple threat of RSV, COVID-19 and flu. That high level of illness presented significant challenges for children’s hospitals handling large surges of patients while caring for children with other medical needs,” Lancaster said.

She says providing kids with the best available protection for all three viruses isn’t just important for safeguarding the well being of individual youths but for maintaining public health.

“Immunizing babies and children help keep the whole community healthier, including those who are immunocompromised and the elderly who are also at risk of severe illness from circulating viruses,” she said.

“This is a proactive approach to disease prevention that can reduce the risk of outbreaks and protect the health of more people in the community while also reducing strain on hospital systems as all these viruses circulate simultaneously.”

More ways to reduce RSV risk

Families of children who aren’t eligible for the new immunizations can take other important health measures this season, Lancaster says, including:

• Keeping the whole family up to date on other immunizations, particularly the COVID-19 and flu vaccinations
• Limiting a baby’s exposure to crowds and people with colds
• Keeping children home from school or childcare when they are sick and teaching them to cover their coughs and sneezes
• Encouraging consistent hand hygiene and regularly washing hands with soap and water, scrubbing for at least 20 seconds
• Disinfecting objects and surfaces in the home regularly
• Feeding babies breastmilk when possible because of its unique antibodies that help prevent and fight infections

“Everyday preventive measures, such as washing hands and covering coughs, will help limit the spread of RSV and other respiratory illnesses during fall and winter seasons,” Lancaster said.

Get more information

Learn more about the RSV immunization.