In an analysis of 140 children with no evidence of previous Covid-19 infection, antibody levels against the original SARS-CoV-2 strain were six times higher one month after a booster dose than a month after the second vaccine dose.
Studies from the New York State Department of Health and the US Centers for Disease Control and Prevention found that the effectiveness of the Pfizer vaccine for children aged 5 to 12 years decreased significantly during the Omicron surge, dropping from 68% to about 12% against Covid-19 infection. However, two doses continued to provide protection against severe illness resulting in urgent care or hospitalization.
More than 10,000 children aged 6 months to 12 years have been enrolled in Pfizer’s Covid-19 vaccine trials at study sites around the world. The companies expect to provide data from these trials focused on children under the age of 5 in the coming months. This age group is the only one for which the Covid-19 vaccine is not authorized in the United States.
Pfizer and BioNTech said they plan to submit this data to the European Medicines Agency and other regulatory agencies for authorization in the coming weeks.
An initial two-dose series of the Pfizer Covid-19 vaccine was licensed in the United States for children ages 5 to 11 in October. Boosters are also available for children 12 and older with certain types of immunodeficiency conditions, as well as adults. The use of second boosters is permitted for anyone 50 years of age or older.