Pfizer and BioNTech have reported topline findings from a Phase II/III clinical trial, where a third 3µg dose of their Covid-19 vaccine induced a robust immune response in children aged six months to below five years.
The trial analysed a third dose of the vaccine in 1,678 children a minimum of two months following the second dose when the Omicron variant of the SARS-CoV-2 virus was predominant.
Findings showed that the vaccine had a favourable safety profile in line with placebo.
Furthermore, the secondary endpoint in the trial, vaccine efficacy was found to be 80.3% in children of this age group.
The immunogenicity assessment of geometric mean titer (GMT) ratio and seroresponse rate was carried out on a subset of trial subjects a month after administering the third dose in children aged six months to below five years versus the second vaccine dose in people aged 16 to 25 years.
For both co-primary endpoints, non-inferiority was met for the six- to 24-month-old population and the two to below five years population.
In addition, three 3µg doses of the vaccine were found to be well-tolerated in subjects of this age group without any new safety signals detected.
Most adverse events were observed to be mild or moderate in nature.
The safety, immunogenicity and vaccine efficacy findings for three vaccine doses in children aged below five years are in line with those reported in adults, indicating that a third dose will offer similar benefits in children.
The companies intend to submit the latest data on three vaccine doses to the US Food and Drug Administration (FDA) under the rolling Emergency Use Authorization (EUA) application process.
Pfizer chairman and CEO Albert Bourla said: “Our Covid-19 vaccine has been studied in thousands of children and adolescents and we are pleased that our formulation for the youngest children, which we carefully selected to be one-tenth of the dose strength for adults, was well tolerated and produced a strong immune response.
“These topline safety, immunogenicity and efficacy data are encouraging, and we look forward to soon completing our submissions to regulators globally with the hope of making this vaccine available to younger children as quickly as possible, subject to regulatory authorisation.”
The latest development comes after the FDA granted EUA for a booster dose of vaccine in children aged five to 11 years.