Hospitalization rates for Covid-19 among adolescents ages 12 to 17 rose between March 1 and April 24 after declining in January and February, according to a recent CDC report, a trend that CDC Director Rochelle Walensky said has her "deeply concerned."

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Covid-19 hospitalizations rise among teens

For the report, researchers looked at CDC's COVID-NET surveillance system, which draws data from 99 counties in 14 states, representing about 10% of the U.S. population.

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Researchers identified 204 adolescents hospitalized primarily for Covid-19 between Jan. 1 and March 31. Of those, more than 30% were admitted to the ICU, and almost 5% needed mechanical ventilation.

Around 70% of the hospitalized adolescents had at least one underlying medical condition—most commonly obesity, chronic lung disease, or neurological disorders.

Henry Bernstein, a pediatrician at Cohen Children's Medical Center and member of CDC's Advisory Committee on Immunization Practices, noted that this means 30% of the hospitalized adolescents were "perfectly healthy" before they contracted the coronavirus.

"So it's not just those [who] have underlying conditions [who] need to be vaccinated," Bernstein said. "Everyone needs to be vaccinated."

"I am deeply concerned by the numbers of hospitalized adolescents and saddened to see the number of adolescents who required treatment in intensive care units or mechanical ventilation," Wolensky said.

Researchers also found the cumulative number of Covid-19 hospitalizations among adolescents between Oct. 1, 2020, and April 24, 2021, was nearly three times higher than hospitalizations for influenza over three recent flu seasons.

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"Flu very rarely causes long-term symptoms and organ damage—unlike Covid-19," Andrew Pavia, a professor of pediatrics and infectious diseases at the University of Utah, said. "Adolescents have many reasons to get vaccinated as soon as possible, including their own health, the ability to help control Covid-19 among more vulnerable groups, and the ability to return to normal life."

Some experts suggested CDC's report may actually undercount the number of children hospitalized as a result of Covid-19, as it documented only cases involving positive Covid-19 tests and didn't account for those hospitalized with multisystem inflammatory syndrome in children (MIS-C), which can develop after a Covid-19 infection has otherwise resolved.

"A majority of kids with MIS-C don't necessarily have a positive PCR test. They are more likely to have antibody evidence of having had the infection, but those things are not being tested," Bernstein said. "We may in fact be underestimating severe Covid-19 associated disease among teenagers."

Where the US vaccination effort stands

According to CDC, as of Sunday, 51.5% of the U.S. population has received at least one dose of a Covid-19 vaccine, and 41.9% have received all required vaccine doses. Meanwhile, 63.5% of U.S. adults have received at least one dose, while 52.8% have completed all required vaccine doses. The United States also surpassed 300 million vaccine doses administered on Sunday, CDC said.

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Meanwhile, according to CDC, the seven-day average of new daily Covid-19 cases dropped from 65,053 on April 1 to 12,780 on June 5. During that same time period, the seven-day average of Covid-19 deaths dropped from 681 to 367.

However, vaccination rates have slowed, dropping from a peak seven-day average of 1.96 million doses on April 11 to 444,000 doses on May 31, according to CDC.

Vaccination rates are especially low in certain areas of the country. For example, in Alabama, Louisiana, Mississippi, Tennessee, West Virginia, and Wyoming, less than 50% of adults have received any vaccine doses.

And experts warn that slowing vaccination rates could be dangerous for children in the United States. "What we also see is that the same places where adults are lagging, teens are lagging," Anand Swaminathan, an ED physician, said.

"We need to bring the vaccines to where people are and answer the questions that people have," Jeff Zients, White House coronavirus coordinator, said. "And we are confident that more and more people will get vaccinated, leading up to the Fourth of July."

"Vaccination is our way out of this pandemic," Walensky said. "I continue to see promising signs in CDC data that we are nearing the end of this pandemic in this country; however, we all have to do our part and get vaccinated to cross the finish line" (Lenghi, CBS News, 6/5; Rodriguez, USA Today, 6/4; Sun, Washington Post, 6/4; Silverman, CNN, 6/7; Maxouris, CNN, 6/6; Pereira, ABC News, 6/6; Diamond et. al., Washington Post, 6/6).