Pfizer Begins Study of COVID-19 Pill in High-Risk Children

A box of Paxlovid, Pfizer's COVID-19 pill, is seen in a file image. Jennifer Lorenzini/Reuters

Pfizer has started a study of its COVID-19 pill in children who have COVID-19 and are designated as being at high risk for experiencing severe symptoms.

The phase 2/phase 3 study has about 140 participants between the ages of 6 and 17.

One cohort will receive Pfizer’s pill, known as Paxlovid or nirmatrelvir, twice a day for five days. The other group will follow the same schedule, but receive a dosage equal to half as much.

Both cohorts will also take ritonavir, an antiviral drug.

Pfizer says the pill is needed because although children are less likely to require hospital care after contracting COVID-19, a number of kids have been hospitalized with COVID-19 during the pandemic.

“There is a significant unmet need for outpatient treatments that can be taken by children and adolescents to help prevent progression to severe illness, including hospitalization or death,” Mikael Dolsten, Pfizer’s chief scientific officer, said in a statement. “We are proud to expand studies of our novel COVID-19 treatment to include pediatric participants to further evaluate the safety and efficacy of this treatment in this important population.”

Paxlovid is authorized or approved for use in many countries, including the United States.

U.S. regulators cleared the pill in late 2021 for use by Americans 12 and older who weigh at least 40 kilograms (about 88 pounds), who tested positive for COVID-19, and who are deemed at high risk of progression to severe COVID-19.

“This authorization provides a new tool to combat COVID-19 at a crucial time in the pandemic as new variants emerge and promises to make antiviral treatment more accessible to patients who are at high risk for progression to severe COVID-19,” Dr. Patrizia Cavazzoni, director of the Food and Drug Administration’s Center for Drug Evaluation and Research, said in a statement at the time.

The authorization was based largely on a Pfizer-run study that showed the pill reduced the risk of hospitalization or death by 89 percent if taken shortly after symptoms initially appear.

But regulators used modeling to try to determine if children should get the pill, because the study only included adults.

“The safety and effectiveness of Paxlovid have not yet been directly established in pediatric patients,” Pfizer said in a statement about the new study to test the pill in children.

Depending on what the study shows, the recommended dosage for children could be changed.

The United States has purchased approximately 10 million courses of Paxlovid, agreeing to pay more than $5 billion. The government also bought about 3 million courses of a similar pill from Merck for about $2.2 billion.

Jack Phillips contributed to this report.