The Predicted 'Tripledemic' Is Here: Why Isn't There an RSV Vaccine?

Just as experts predicted, American hospitals are battling a triple threat of respiratory viruses this holiday season with RSV, COVID-19, and the flu.
By on 12/02/2022 2:00 PM

Source: MedicineNet Health News

Just as experts predicted, American hospitals are battling a triple threat of respiratory viruses this holiday season with RSV, COVID-19, and the flu.

Unlike COVID-19 and the flu, there is no vaccine yet available for RSV. And unlike COVID-19, RSV is particularly harmful to children. Every year, RSV causes an average of 58,000 hospitalizations in children under age 5, says the National Institute of Allergy and Infectious Disease.

Hospitals around the country are reporting surges in RSV cases, like Blank Children's Hospital in Des Moines, Iowa, which registered 165 pediatric patients to ER in a 24-hour period on Saturday—a new record, according to KCCI News. Meanwhile St. Luke's Children's Hospital in Idaho was at capacity for pediatric patients on Sunday, according to KTVB News.

If RSV is causing this much trouble, why is there no vaccine for RSV?

Failure Spooked Vaccine Makers

Researchers have been slow to produce an RSV vaccine partly because of a medical disaster that took place in the 1960s.

In 1966, a Washington, D.C. trial of an RSV vaccine had the opposite of its intended effect, sending 80% of test children to the hospital with severe respiratory disease.

Two of the children died. Researchers wouldn't know what went wrong for decades to come.

Most scientists blame formalin, a chemical used to inactivate RSV in the vaccine that could have produced weak antibodies. These weak antibodies could have set back the children's ability to fight off the virus.

An alternate theory came in 2008 in an investigation led by Dr. Fernando P. Polack. His team found that the children's antibodies did not bind to the inactivated virus in the vaccine strongly enough to produce an immune response. Rather, these antibodies drug along the dead virus throughout the body of the vaccinated children, triggering a massive response from their immune system which led to the hospitalizations.

Whatever the reason, the failures of the 1966 experiment continue to haunt RSV vaccine developers.

"A big concern for the scientists involved in RSV vaccine development is to make sure we do not repeat the same situation again," Polack told Reuters Health.

Despite this checkered history, researchers have continued to work on vaccines for RSV.

A Safe Vaccine for RSV

Although there is no vaccine for RSV, that could change as early as next fall. After decades of failure, a new RSV vaccine is finally showing promise when given to pregnant women to protect their newborns.

Pfizer announced earlier this year that their new vaccine is 82% effective at preventing RSV infection within the first 90 days of being born. Known as "RSVpreF," this vaccine showed no safety concerns at trial for either mother or child.

“We are thrilled by these data as this is the first-ever investigational vaccine shown to help protect newborns against severe RSV-related respiratory illness immediately at birth,” said Annaliesa Anderson, Ph.D., Senior Vice President and Chief Scientific Officer, Vaccine Research & Development, Pfizer.

Eric A.F. Simões, M.D., Clinical Professor, Pediatrics-Infectious Diseases, University of Colorado School of Medicine and Children’s Hospital Colorado, Aurora said the vaccine, if approved, would have global significance:

"Every year we see high levels of RSV cases among babies in the U.S., with some regions reporting hospital admission rates higher than normal this year. A maternal vaccine with high efficacy that can help protect infants from birth could substantially reduce the burden of severe RSV among newborns through six months of age."

Meanwhile the pharmaceutical company GSK announced success in October with their RSV vaccine for older adults.

What Is RSV?

Respiratory syncytial virus (RSV) is a highly contagious virus that appears each winter, according to John Mersch, MD, FAAP, writing for MedicineNet. He said that while older children are likely to experience a "bad cold" lasting a week or two, the disease is more serious for younger children.

"In babies and toddlers, RSV can produce severe pulmonary diseases, including bronchiolitis and pneumonia," Mersch wrote.

He said symptoms are similar to that of a cold: a runny nose, fever, cough, watery eyes, and nasal congestion.

"Because severe infections in children can cause respiratory problems that require hospitalization, RSV is one of the leading causes of death in children younger than one year worldwide," Mersch wrote.

Doctors are urging parents to get their children checked out if they feel their children need to be examined. Waiting could be deadly. If your regular doctor isn't available, parents are encouraged to use the emergency departments of their local hospitals as necessary.

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