After the Food and Drug Administration and Pfizer halted their plans for a quick-track authorization, parents of children younger than 5 years will now have to wait until at most April before they can get their child vaccinated against Covid-19.

The FDA originally intended to approve the two first doses of what would eventually be a 3-dose vaccine within this month. The FDA’s vaccine director, Dr. Peter Marks stated that the updated data was submitted by PfizerAnd BioNTechThey did not agree with the idea of getting the first two doses early. Marks said that although the FDA had made an unexpected decision, it continued to follow the science.

Marks stated that “the data we saw made us realise that we required data from a 3rd dose in the ongoing trials in order to make an assessment that we could proceed in doing authorization,” during Friday’s conference call. He did not provide details on the data. 

Acting FDA Commissioner Janet Woodcock said the drug regulator had sought to act swiftly  to protect children against omicron as Covid hospitalizations among the youngest rose to record levels in recent weeks. Woodcock stated that the FDA had to delay information about the third dose because of safety and effectiveness standards. 

Woodcock stated in a statement that the goal of Woodcock’s review was to determine if two doses were sufficient to provide enough protection for the approval to use the vaccine in the age group. Woodcock stated, “Our strategy has been to perform a regulatory review that is responsive to the immediate public health requirements created by the pandemic,” adding that it was always her goal to adhere to strict safety and effectiveness standards.

Woodcock explained that while it was helpful to be able “to begin evaluating first data” during our review of the vaccines, additional information should still be taken into consideration regarding ongoing evaluation of a 3rd dose.

Paul Offit (a member of FDA’s vaccine advisory panel) stated that although the FDA has made the assumption that the third dose is safe and effective, there are no guarantees that it will prove to be true once all data have been received.

Offit is a Philadelphia pediatrician who directs the Vaccine Education Center at Children’s Hospital. “Imagine that we approve it after two doses, then discovering later that the third was not safe and having to back out,” Offit said. “I am glad we are going to wait till we have all of our data before we can make that decision.

Some parents and doctors have been pressuring the FDA in recent weeks to increase eligibility to cover toddlers up to age 4 as the omicron strain swept across the nation. Only children below 5 years of age are eligible to receive vaccination in the United States. 

A seven-day average of data provided by the Department of Health and Human Services shows that nearly 5200 children had been hospitalized for Covid in January 18. This figure is almost twice as high as the peak seen during the fall of 20201. HHS data show that this figure had fallen to just over 3,000 by Friday. 

In a Friday statement, the American Academy of Pediatrics stated that, although this news is disappointing for many parents, it was important to conduct a thorough review to make sure the vaccine works.

The AAP stated that parents should use a careful, transparent and robust process to assess the evidence in the age-group for vaccine approval in order to be confident in giving the vaccine to their kids.

The problem is that the vaccine was not effective in producing an immune response for two children, aged between 2 and 4, who received Pfizer’s or BioNTech’s vaccine during clinical trials. Children under five years of age are being tested for a dose that is three times as low, at 3 micrograms, than older children who have 30-microgram shots.

BioNTech, Pfizer, and BioNTech modified their December clinical trial to examine a third dosage to see if it could produce the required immune response in order to prevent Covid. They had previously stated in December that they would not have data until April.

Pfizer stated that there was an urgent public health need to get children this age vaccinated due to the rapid growth of omicron in the holiday season and into January. Marks stated that parents should be confident in the vaccine and not feel swayed by the FDA’s decision to defer authorization. The FDA has taken responsibility for the change, Marks said. They make decisions on the basis of the available data.

Marks stated, “I hope that this will reassure people that there is a process and that it follows the standard.” “We follow the science and make sure anything we authorise has the safety-enhancing efficacy people expect.

Wayne Koff is the CEO of Human Vaccines Project. He’s also a Harvard professor of epidemiology. Koff said that there are good reasons to believe the third dose of vaccine will increase the effectiveness in children younger than five years. Koff explained that booster doses are effective in the prevention of severe illnesses in older age groups. Therefore, it is a good idea to consider the vaccine a three-dose regimen for all age groups.

Offit indicated that Covid shots will soon be routinely administered to children as a preventative against the spread of poliomyelitis. Although the United States has eliminated polio since the 1970s it continues to vaccinate children because of its spread in certain parts of the globe. Most experts in public health agree that Covid elimination is not possible at the moment.

We will need a protected population over many years. Offit stated that he believes this routine vaccination will be a common childhood vaccine.

Koff stated that the FDA is working to speed up access by gradually lowering the eligibility while still adhering safety and effectiveness standards.

Koff explained that it is important to demonstrate the safety and effectiveness of the vaccine in adults first. Once you can prove that the vaccine is safe and effective in the adult population, you will be able to reduce the age of adolescents first and later the youngest children and finally the infants.

Offit stated that children younger than 18 are less likely to get the disease and it is more common in the elderly. This is why vaccines have been focused first on older people. He suggested that parents should create a “moat around” their children who aren’t eligible for vaccination by making sure they have vaccinated everyone in their lives. 

While about 75% of U.S. adults are fully vaccinated with two doses of the Pfizer or Moderna shots or one dose of the Johnson & Johnson vaccine as of Thursday, that figure is lower for kids. Only 57% are fully vaccinated among children aged 12-17. according to the CDCAnd 24% of the 5 to 11-year-olds.

Nate Rattner from CNBC contributed to this article.