As part of ongoing clinical trials, the American pharmaceutical giant has selected a dosage of 3 micrograms per injection for children aged 6 months to less than 5 years.
This is ten times less than the dosage given to adults (30 micrograms), and also less than that of 5 to 11 year olds (10 micrograms).
In children from 2 years to less than 5 years, a dosage of 10 micrograms indeed caused more fever than in the older groups, pushing the company to select a lower dosage.
But with two injections of 3 micrograms, their immune response was found to be poorer than that given to adolescents and young adults by the vaccine.
Pfizer has therefore decided to modify the protocol of its clinical trials, to include a third dose, injected "at least two months after the second", the company said in a press release (the first two remain injected 3 weeks apart one from the other).
A booster dose has indeed shown, in older population categories, to increase the protection conferred.
This "adjustment" should not have any consequence on the anticipated schedule for the filing of an application for authorization for these young children, expected "in the second quarter of 2022", said on a conference call Kathrin Jansen, head of research for vaccines within the group.
Pfizer also announced Friday that it had started trials on 600 adolescents aged 12 to 17 to test a booster dose (of 10 or 30 micrograms).
Currently in the United States, in addition to adults, a booster dose is only permitted for adolescents 16 and 17 years of age.
© 2021 AFP