Parents hoping that a coronavirus vaccine will soon become available for their babies and young children may be waiting even longer following an announcement that Pfizer’s two-dose regimen fails to trigger an effective immune response in kids two to five years old.
Pfizer and BioNTech announced Friday that they are now modifying their clinical trial to include a third shot at least two months after the second dose.
Although the vaccine did generate an adequate immune response in children six months to two years old, the companies reported that two doses of the pediatric vaccination – at 3 micrograms each, they are one-tenth of the adult dose – was not as robust in 2-, 3-, and 4-year-olds as compared to people 16 years and older.
Instead of testing a larger amount of micrograms per dose in the two-to-five age range, they plan to introduce an additional dose.
“The study will now include evaluating a third does of 3 [micrograms] 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 in a statement.
This new round of testing will cause a delay in submission of data to regulators to authorise use in the U.S. Pfizer says they expect to file results in the “first half of 2022,” barring the success of the trials.
To date, the Food and Drug Administration has authorised the Pfizer vaccine for emergency use in children five years and older.
