Parents of children under 5 will need to wait longer for a COVID-19 vaccine as the Food and Drug Administration (FDA) and Pfizer-BioNTech have delayed plans to fast-track authorization. The decision follows updated data indicating that two doses of the vaccine did not elicit a sufficient immune response in children aged 2 through 4.
Data Insufficiency Prompts Delay
The FDA's initial plan was to authorize the first two doses of a planned three-dose vaccine regimen as early as February. However, according to Dr. Peter Marks, head of the FDA's vaccine division, the data submitted by Pfizer and BioNTech necessitated waiting for data from a third dose. "The data that we saw made us realize that we needed to see data from a third dose in the ongoing trial in order to make a determination that we could proceed with doing an authorization," Marks told reporters.
Safety and Efficacy Standards Maintained
Acting FDA Commissioner Janet Woodcock emphasized that the agency sought to act swiftly due to rising COVID-19 hospitalizations among young children, which peaked in mid-January with nearly 5,200 hospitalizations. However, the FDA's rigorous safety and efficacy standards required waiting for more information. "Our approach has always been to conduct a regulatory review that's responsive to the urgent public health needs created by the pandemic, while adhering to our rigorous standards for safety and effectiveness," Woodcock stated.
Third Dose Anticipated to Improve Response
The problem identified was that two doses of the Pfizer-BioNTech vaccine, administered at a lower 3-microgram dose compared to the 30-microgram dose for older children and adults, did not produce an adequate immune response in the 2-4 age group during clinical trials. Pfizer and BioNTech amended their clinical trial in December to evaluate a third dose, with data expected in April.
Wayne Koff, CEO of the Human Vaccines Project, expressed optimism that the third dose would improve vaccine effectiveness, citing the success of booster doses in other age groups. "Being able to begin evaluating initial data has been useful in our review of these vaccines, but at this time, we believe additional information regarding the ongoing evaluation of a third dose should be considered," Woodcock said.
Future Implications for Childhood Immunization
Dr. Paul Offit, a member of the FDA's vaccine advisory committee, suggested that the COVID-19 shot will likely become a routine childhood vaccine, similar to the polio vaccine. He highlighted the need to maintain a highly protected population for years to come. While approximately 75% of U.S. adults are fully vaccinated, vaccination rates are lower among children, with roughly 57% of those aged 12-17 and 24% of those aged 5-11 fully vaccinated, according to the CDC.
