Despite mixed results, Pfizer seeks shots OK
Two-shot vaccine approval sought for children under 5
WASHINGTON » Pfizer and its partner, BioNTech, asked the Food and Drug Administration on Tuesday to authorize two doses of their coronavirus vaccine for children younger than 5 while the companies continue to research whether three doses would be more effective for that age group.
In a highly unusual move, federal regulators pressed the companies to submit a request for emergency authorization, even though two doses failed to produce the hoped-for immune response among children ages 2 to 4 in a clinical trial. Only children between 6 months and 2 years old demonstrated an immune response comparable with that of older teenagers and young adults, the standard for a successful trial. The doses were one-tenth the strength of adult doses.
The request, which applies to children 6 months to 4 years old, comes as the highly contagious omicron variant has led to many more infections. The under-5 group includes about 19 million children.
The disappointing trial results, announced in December, prompted the companies to test a third low dose of the shot in the age group.
But rather than wait until the end of March for those results to come in, federal regulators decided to encourage the companies to apply for authorization of a two-dose regimen in order to get a head start on the vaccination effort.
In meetings about the strategy, government officials argued that two doses had proved safe, even if they failed to meet the criteria of producing an immune response in the whole age group, according to multiple people familiar with the discussions. If children get an initial injection this month, some officials reasoned, they could be ready for a third dose by the time researchers obtain what they hope will be successful results from the three-dose trial. The first two doses would be spaced three weeks apart, followed by a third dose two months after the second.
Albert Bourla, Pfizer's chair and CEO, said in a statement: “Ultimately, we believe that three doses of the vaccine will be needed for children 6 months through 4 years of age to achieve high levels of protection against current and potential future variants. If two doses are authorized, parents will have the opportunity to begin a COVID-19 vaccination series for their childrene.”
The companies' study of younger children was designed to measure immune responses, not the vaccine's efficacy in preventing virus infections or severe cases of COVID-19. But because some children in the trial became infected, researchers picked up indications of how well the vaccine worked to stave off the virus, two people familiar with the study said.
A similar development occurred in the companies' study of their vaccine in 5- to 11-year-olds, which overlapped with a crushing wave of the delta variant.