Pfizer and BioNTech had initially planned a two-dose regimen for children younger than 5, but added the third dose when just two failed to offer the expected level of protection against the coronavirus.
Each of the three doses contains three micrograms of vaccine, about one-tenth of an adult dose. Children under 5 is the only age group in the United States for whom there is no authorized COVID-19 vaccine.
"Our COVID-19 vaccine has been studied in thousands of children and adolescents, and we are pleased that our formulation for the youngest children, which we carefully selected to be one-tenth of the dose strength for adults, was well tolerated and produced a strong immune response," Pfizer CEO Albert Bourla said in a statement Monday.
Federal regulators are reviewing a two-dose regimen for children under 5 produced by Moderna and are expected to make a decision on authorization in the coming weeks. File Photo by Debbie Hill/UPI
Dr. Ugur Sahin, CEO and co-founder of BioNTech, said in a statement that the companies expect to submit the study data to the U.S. Food and Drug Administration for review this week, and the European Medicines Agency and other global regulators later.
Pfizer and BioNTech added the third dose, given two months after the second dose, in December amid rising cases worldwide related to the Omicron variant.
"The safety, immunogenicity and vaccine efficacy data for three doses of the vaccine in children under 5 years of age are consistent with the data seen in adults, suggesting that a third dose will provide similar benefit in children," the companies said in a statement.
Data from the Centers for Disease Control and Prevention show that there have been more than 400 coronavirus-related deaths in the United States among children under 5 since the start of the pandemic in early 2020. CDC data from Friday showed an average of 35.6 new weekly cases per 100,000 young children in that age group.