Dr. Scott Gottlieb pointed out the highly transmittable Covid-19 variants on Friday as a possible cause of an increase in adolescents hospitalized with the virus in March and April.

“It’s worrying the trends in hospitalization” among teenagers, said Gottlieb, the former head of the Food and Drug Administration during the Trump administration. “I think it’s a reflection of the new, more contagious varieties.”

“We see that these variants are more contagious in all age groups, so that they affect more adults, but also more children, so that more children get sick with symptomatic Covid infection and more children are hospitalized as a result, especially B. 117”, Gottlieb told CNBC’s “The News with Shepard Smith”.

The B. 117 variant is currently the most prevalent strain in the United States with 20,915 reported cases, according to the Centers for Disease Control and Prevention.

In the first three months of the year, CDC researchers found that almost a third of adolescents hospitalized with Covid had to be admitted to an intensive care unit. In the meantime, 5% required invasive mechanical ventilation. Of course, CDC data shows that no teenagers died from Covid in the US in the first quarter of 2021.

CDC director Rochelle Walensky called on parents on Friday to vaccinate their teenagers against Covid, citing other teenagers who were hospitalized with Covid.

Disclosure: Scott Gottlieb is a CNBC employee and a member of the board of directors of Pfizer, genetic testing startup Tempus, health technology company Aetion Inc., and biotechnology company Illumina.