A third dose of Pfizer Inc and BioNTech's Covid vaccine produced significant protection against the Omicron variant in healthy children aged between 5 and 11 years in a trial, the companies said on Thursday.
Blood serum analysis of a few pediatric participants who received a booster dose in the study showed a 36-fold increase in Omicron neutralizing antibodies, the drugmakers said.
Neutralizing antibodies against SARS-CoV-2 wild-type strain rose six-fold following the booster shot.
The mid-to-late stage study was testing the safety and immunogenicity of a 10 microgram booster dose in 140 healthy children aged 5 through 11 years.
Pfizer and its German partner said the data reinforces potential function of a third dose of the vaccine in maintaining high levels of protection against the virus in this age group.
The companies plan to apply for Emergency Use Authorization of a booster dose in the 5-11 age group in coming days, with additional submissions to global regulatory agencies including the European Medicines Agency to follow.
Earlier this year, the US Food & Drug Administration authorized a third dose of the vaccine for children ages 12 to 15 and those aged 5 through 11 years who are immunocompromised.
The agency at the time said it will weigh boosters for 5 to 11 year olds after more children receive two doses.
According to the Centers for Disease Control & Prevention (CDC), about 8 million children aged between 5 and 11 in the United States are fully vaccinated.