The challenges of treating RSV in children… without a vaccine

This is part 2 of the interview with Dr. Varga. Click here to watch part 1 and hear more about the failed vaccine trials that paved the way for the world’s first RSV vaccine.

We’re hearing about respiratory syncytial virus (RSV) now more than ever, and it’s not just because the world’s first RSV vaccine was approved by the FDA for older adults last week.

“I know RSV has gotten a lot of press over the past year,” says Steven Varga, PhD. “I think that was partly due to the disruption of normal seasonality associated with RSV.”

Varga is a member of the St. Jude Children’s Research Hospital faculty of the Department of Infectious Diseases, as well as Dean of the St. Jude Graduate School of Biomedical Sciences.

Varga explained that prior to COVID-19, RSV has a predictable seasonality, starting in the fall and peaking in the winter. At the height of the COVID-19 pandemic, when many people wore masks, sanitized and adhered to social distancing recommendations, “the number of RSV cases, as well as flu and many other respiratory viruses, suddenly dropped because we took measures to prevent spread.”

As the number of COVID-19 infections declined, protections were lifted, causing RSV infections to return in unexpected ways. “We saw this large increase in cases occurring relatively late in the spring and into the summer, and particularly in the geographic southern regions of the US,” Varga explains. “That got a lot of public attention, because it was so off-cycle and because so many kids got sick.”

Young children and infants are susceptible to the worst RSV infection; their bodies build up mucus to defend against RSV, but this can actually block their growing airways and make the disease worse.

“In very young children, their airways are very narrow because they are still developing,” Varga said. “They’re much more susceptible to blocked airways from that mucus, especially at night when they’re horizontal.”

RSV is “a ubiquitous pathogen,” Varga said, noting that virtually all children contract RSV by age 3, and adults will unknowingly experience multiple reinfections. Because COVID-19 preventative practices kept RSV from circulating for years, many children are now being exposed to RSV for the first time.

This led to a large number of susceptible children who all had to be treated at the same time. “The problem with treatment is that there are no good antiviral treatments available that are specific to RSV,” Varga said. The options are low in efficacy or very expensive, so Varga explained that most of the care provided is supportive, such as oxygen for breathing and fluids to prevent dehydration.

Varga emphasized: “We don’t have a lot of options for treatment, which is why the news about vaccines is so exciting…possibilities for treating children in particular.”

As more RSV vaccines approach approval, including a new maternal vaccine to protect newborns against RSV, stay tuned for Infection‘s cover.

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