Pfizer on Wednesday asked the US to authorize extra-low doses of its Covid-19 vaccine for children under five, potentially opening the way for the very youngest Americans to start receiving shots as early as March.

In an extraordinary move, the Food and Drug Administration (FDA) had urged Pfizer and its partner BioNTech to apply earlier than the companies had planned.

The nation’s 19 million children under five are the only group not yet eligible for vaccination against the coronavirus. Many parents have been pushing for an expansion of shots to toddlers and preschoolers, especially as the omicron wave sent record numbers of youngsters to the hospital.

I would say the parents in my office are desperate to get their youngest kids vaccinated, said Dr Dyan Hes, who runs a pediatrics practice in New York City where vaccination rates are high. For many, that’s the first thing they ask when they walk through the door: When do you think the shot is going to come out?’

If the FDA agrees, Pfizer shots containing one-tenth of the dose given to adults could be dispensed to children as young as 6 months. Pfizer said Wednesday it had started submitting its data to the FDA and expects to complete the process in a few days.

An open question is how many shots those youngsters will need. Two of the extra-low doses turned out to be strong enough for babies but not for preschoolers in early testing. Pfizer is testing three shots, and the final data is expected in late March.

That means the FDA may consider whether to authorize two shots for now, with potentially a third shot being cleared later if the study supports it.

The FDA said Wednesday it will convene a panel of independent researchers and physicians in mid-February to help review the Pfizer data. The agency isn’t required to follow their advice, but their input is a key step in publicly vetting vaccine safety and effectiveness.

The question of how long to wait for new vaccine data and how much to require is a concern for FDA regulators, who face pressure to be more proactive against a virus that has repeatedly confounded health experts.

The FDA asked Pfizer to begin submitting its application now due to omicron’s greater toll on children, an agency spokeswoman said, citing record cases among children under 5.

In light of these new data and the rise in illnesses and hospitalization in this youngest age group, FDA believed that it was prudent to request that Pfizer submit the data it had available, agency spokeswoman Stephanie Caccomo said in an emailed statement.

The FDA’s ultimate decision could come within the month but that isn’t the only hurdle. The Centers for Disease Control and Prevention also has to sign off.

The Biden administration has been trying to speed the authorization of COVID-19 shots for children, contending vaccinations are critical for opening schools and day care centers and keeping them open, and for freeing up parents from child care duties so they can go back to work.

Yet vaccination rates have been lower among children than in other age groups. As of last week, just 20 per cent of kids ages 5 to 11 and just over half of 12- to 17-year-olds were fully vaccinated, according to the American Academy of Pediatrics. Nearly three-quarters of adults are fully vaccinated.

While young children are far less likely than adults to get severely ill from the coronavirus, it can happen, and pediatric COVID-19 infections are higher than at any other point in the pandemic.

What we’re seeing right now is still a lot of hospitalizations and unfortunately some deaths in this age group, said Dr Sean O’Leary of the University of Colorado, who is on the AAP’s infectious disease committee. If the FDA clears vaccinations for these youngsters, that’s going to be really important because all of those hospitalizations and deaths essentially are preventable.

Chicago health officials have been trying to prepare parents for months for the day the shots are available, said Dr Nimmi Rajagopal, a family medicine physician for Cook County Health, which oversees the public hospital system. Some parents wonder how rigorously the shots will be evaluated or have other questions that she said are critical to address.

Rajagopal is excited about getting her own two-year-old son vaccinated if FDA clears the way, so it will be safer for him to play with other children. “I have been waiting and waiting and waiting,” she said. 

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