Pfizer-BioNTech Postpones FDA Application to Vaccinate Children Under 5

On February 1, Pfizer and its partner BioNTech asked the US Food and Drug Administration (FDA) to approve its 2-dose COVID-19 vaccine regimen for children younger than 5 years of age.

Today, the companies announced they would be postponing their case as they wait for more data to advise the rollout of the low-dose mRNA COVID-19 vaccine in children as young as 6 months.

Pfizer-BioNTech had pushed for FDA approval despite some trial evidence suggesting 2 doses of its vaccine did not evoke the desired autoimmune response. Only children 6 months-2 years old demonstrated an adequate immune response after 2 doses of Pfizer-BioNTech’s COVID-19 vaccine; vaccine trial doses for young children were 3 mg, or 1/10 the strength of the adult doses.

Pfizer-BioNTech deferring the Emergency Use Authorization (EUA) request to wait for more conclusive evidence of adequate autoimmune response comes as a bit of a shock. On Tuesday, Pfizer CEO Albert Bourla stated that the chance was “very high” the FDA would authorize their vaccine in children under 5.

"I think that they will be pleased with the data and they will approve," Bourla told CNBC.

Now, Pfizer-BioNTech is saying they will wait for data on a 3-dose vaccine regimen before requesting to administer vaccines in children 6 months-4 years old.

Pfizer-BioNTech received approval on December 17, 2021 from the FDA and European Medicines Agency to add a third dose to its clinical vaccine trial of children 6 months to 4 years old. At the time they announced the dosage change, Pfizer-BioNTech said, “These updates were informed by the effectiveness data for three doses of the vaccine for people 16 years and older, and the early laboratory data observed with Delta and other variants of concern, including Omicron, which suggest that people vaccinated with three doses of a COVID- 19 vaccine may have a higher degree of protection.”

Pfizer-BioNTech backtracked in hopes that data from the 3-dose trial will show a higher autoimmune response in young children. They anticipate results from the third dose trial to be available in early April.

The FDA previously announced its Vaccines and Related Biological Products Advisory Committee (VRBPAC) will meet on February 15 to discuss Pfizer-BioNTech’s request for Emergency Use Authorization (EUA) to deploy its vaccine among children 6 months-4 years of age.

The FDA noted the concerning rise in hospitalizations of young children with severe COVID-19 disease, as the highly infectious Omicron variant continues to spread.

"Having a safe and effective vaccine available for children in this age group is a priority for the agency and we're committed to a timely review of the data, which the agency asked Pfizer to submit in light of the recent Omicron surge. Furthermore, children are not small adults. Because they're still growing and developing, it's critical that these vaccines are evaluated in well-designed and well-conducted clinical trials," acting FDA commissioner Janet Woodcock, MD, said in a statement.

Currently the only COVID-19 vaccine approved for children and adolescents under 18 years, Pfizer-BioNTech’s vaccine has been shown to wane in efficacy after a few months. For this reason, and due to Omicron’s unprecedented ability to cause breakthrough infections, the FDA and US Centers for Disease Control and Prevention (CDC) updated their booster vaccine recommendations.

Now, all persons 12 and older are strongly recommended to receive an additional mRNA booster vaccine:

• 6 months after initial vaccination for Moderna (mRNA-1273) recipients
• 5 months after initial vaccination for Pfizer-BioNTech (BNT162b)
• 2 months after initial vaccination for Janssen (Johnson & Johnson; Ad26.COV2.S) recipients
• Both mRNA vaccines are currently preferred over the Janssen vaccine, as boosters and as a primary series, though vaccination with Janssen is recommended if no other COVID-19 vaccine is available.