Comedian Amy Schumer missed one of the rehearsals for Saturday Day Night Live last week after her son was admitted to the hospital. She said he was suffering from RSV.
Despite missing Thursday's rehearsal, Schumer was still able to host the show on Saturday.
She said her son, who is three years old, was discharged and is doing better, but she empathized with other parents in similar situations.
"Shout out to all the parents," Schumer said.
The Centers for Disease Control (CDC) said surveillance had shown an increase in RSV at hospitals across the country.
The respiratory virus can be especially dangerous for infants and older adults.
There is no specific treatment for RSV. Most infections go away on their own within two weeks, according to the CDC.
Pfizer is seeking regulatory approval for an RSV vaccine. It would be given to pregnant women to prevent their babies from getting the virus. Pfizer said its vaccine is nearly 82% effective at preventing severe cases of RSV in a baby's first 90 days of life.