A low dose of the Pfizer-BioNTech coronavirus vaccine failed to produce an adequate response in children aged two through five years of age.
The companies announced the results from ongoing critical trials on Friday and said that after testing children 6 months to 5 years of age with one–tenth of the adult dose, children between 6 months and 2 years produced an immune response similar to people aged 16 to 25 after two doses but children between 2 and 5 did not.
“The companies will amend the clinical study evaluating the safety, tolerability, and immunogenicity of the Pfizer-BioNTech COVID-19 Vaccine in children 6 months to under 5 years of age,” the statement said. “The study will now include evaluating a third dose of 3 µg at least two months after the second dose of the two-dose series to provide high levels of protection in this young age group.”
The companies said if the three-dose study is successful, they plan to apply for emergency authorization sometime in the first half of 2022.