Pfizer Inc and BioNTech SE said recently that three doses of their COVID-19 vaccine generated a strong immune response in children under age of five years, and was safe and well-tolerated in their clinical trial.
The companies said they plan to soon ask global regulators to authorise the shot for the age group, children for whom no vaccine is currently approved in most of the world. They said they expect to complete their submission of data to the US Food and Drug Administration (FDA) this week.
The clinical trial involved giving 1,678 children aged six months to under five years old smaller doses of the vaccine than given to older children and adults. Pfizer and BioNTech said that three shots of a 3 mg formulation of their vaccine generated a similar immune response in that age group as in 16 to 25-year-olds who had received two doses of the 30 mg formulation of the vaccine in an earlier clinical trial.
“The study suggests that a low 3 mg dose of our vaccine, carefully selected based on tolerability data, provides young children with a high level of protection against the recent COVID-19 strains,” Ugur Sahin, Chief Executive, BioNTech, said in a statement.
Moderna released trial data in March showing that its vaccine was safe and generated a similar immune response in young children as for adults.
New York-based Pfizer and Germany-based BioNTech said that an early analysis of 10 symptomatic COVID-19 cases identified through 29th April, while the Omicron variant was dominant, suggested a vaccine efficacy of 80.3 per cent in the under-five years age group. This analysis was not conclusive, as the trial’s protocol specified that efficacy should be calculated based on at least 21 cases.
Pfizer and BioNTech said final efficacy data in the age group will be made public when it is available.
The drugmakers had previously tested two doses of the 3 mg vaccine in the children. However, the two-dose trial failed to meet its primary endpoint after results for children aged two to four showed a weaker immune response than in adults.
The trial participants received their third dose at least two months after their second shot. Pfizer said the vaccine was well-tolerated, with most adverse side effects being mild or moderate.
The Pfizer/BioNTech shot is currently authorised for use in all Americans aged five years and older. Children aged five to 11 years receive two 10 mg doses as their primary course, while people aged 12 years and older receive two 30 mg doses.
It was not clear how many American parents will vaccinate their children in the age group. Only 29 per cent of American children aged five to 11 years are fully vaccinated, and COVID-19 is generally more mild in children than in adults.
The US regulators are already preparing to review the data in younger children as well as data submitted by Moderna for children under age six years. The FDA said recently that a committee of its external advisors will meet on 15th June in order to consider the use of the two vaccines in the youngest children.
Moderna has said two 25 mg shots of its vaccine were around 37 per cent effective in preventing infections in children aged two to five years and 51 per cent effective for children aged six months to two years.
Edits by EP News Bureau