Low-dose Pfizer-BioNTech vaccine fails in trial on 2 to 5 year olds

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.