Pfizer Delays Plans to Seek Authorization of Covid-19 Vaccine for Young Children

Many parents of young children, who don’t have any Covid-19 vaccines available for use, have been looking forward to clearance of the shots.

In September, Pfizer said it expected to get study data in the young children in the following weeks, and would apply to the Food and Drug Administration soon after.

Testing in young children has been taking longer than researchers expected because of the work required to prepare doses. Also, federal health regulators demanded that more children be enrolled in the studies than originally planned, and enrolling children takes much longer than adults because it requires parents’ consent. Some young volunteers don’t work out because they recoil at needles.

The FDA has cleared use of the two-dose vaccine in people as young as 5 years old, under an emergency use authorization, and of a third, booster dose in those 16 years and older. This week, Pfizer asked the FDA to approve the vaccine’s use in children 12 to 15 years.

Under the companies’ plans, young children take 3 micrograms of the vaccine, which is one-tenth of the dose people 12 years and older receive.

In testing, researchers saw the desired immune response in a study of children 6 months to 2 years, the companies said. That response, a measure of antibody levels following vaccination, was comparable to that of people aged 16 to 25 years, the companies said.

However, researchers didn’t see that kind of response in children between two and five years, the companies said.

The companies didn’t give a reason for the unexpected performance but said they wanted to test the additional dose because it could provide more protection that could be helpful with Delta and Omicron variants circulating.

Pfizer and BioNTech said the additional testing shouldn’t cause a delay in seeking authorization during the first half of 2022.

No serious safety concerns were observed in the youngsters, according to the companies.

Children are at lower risk of Covid-19 infection than adults, health experts said. When children are infected, they tend to experience milder symptoms. Yet some can become seriously ill and some can spread the virus.

Pfizer and BioNTech also said they would begin studying booster doses in 5- to 11-year-olds, who receive a dose one-third the size as adults.

The companies have already begun evaluating third doses in children 12 to 17 years.

Pfizer decided to study booster doses in the various populations because existing data showed their benefit to adults and laboratory tests suggest booster shots are effective against Omicron and Delta variants,

Kathrin Jansen,

Pfizer’s head of vaccine research, said on a conference call with investors.

“If successful with the strategy and following consultation with regulatory authorities, we would have a consistent three-dose vaccine approach for all ages,” she said.

Write to Jared S. Hopkins at [email protected]