People infected with Respiratory Syncytial Virus (RSV) usually show symptoms 4-6 days after infection.
Cases of RSV continue to surge in the U.S., but a vaccine to protect young children against the respiratory virus remains a long ways off.
RSV, or respiratory syncytial virus, is the most common cause of bronchiolitis and pneumonia in children under 1, causing thousands of pediatric hospitalizations and hundreds of deaths each year, according to the Centers for Disease Control and Prevention.
That there is no RSV vaccine for kids is not for lack of interest, experts say. But a trial gone wrong many years ago and a tricky target protein have made developing an RSV vaccine difficult.
Researchers’ attempts to develop an RSV vaccine go back decades, according to Dr. Ofer Levy, the director of the Precision Vaccines Program at Boston Children's Hospital.
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In the 1960s, a pediatric hospital in Washington, D.C., developed a vaccine for the virus and conducted a clinical trial on it in young children. But things quickly went awry.
Instead of protecting against RSV, the experimental vaccine made the children more likely to develop more severe illnesses if they got infected. Many children in the trial were hospitalized, and two young children died.
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