The pharmaceutical company Moderna has started a study testing its Covid vaccine in children under the age of 12, including babies as young as six months, the company said Tuesday.
The study is expected to enroll 6,750 healthy children in the United States and Canada.
"There is a great demand for information about vaccination for children and how it works," said Dr. David Wohl, the medical director of the University of North Carolina Vaccination Clinic, who is not involved in the study.
In a separate study, Moderna is testing its vaccine on 3,000 children aged 12 to 17 years.
Many parents want protection for their children, and vaccinating children should help establish the herd immunity that is believed to be critical to ending the pandemic. The American Academy of Pediatrics has called for vaccine studies to be expanded to include children.
Every child in Moderna's study receives two recordings 28 days apart. The study will consist of two parts. In the first case, children aged 2 to under 12 can receive two doses of 50 or 100 micrograms each. People under the age of 2 may receive two exposures of 25, 50, or 100 micrograms.
In each group, the first children to be vaccinated are given the lowest doses and monitored for reactions before later participants are given higher doses.
The researchers then conduct an interim analysis to determine which dose is the safest and most effective for each age group.
Children in the second part of the study receive the doses or placebo shots selected by the analysis, which consist of salt water.
The children will be followed for a year to look for side effects and measure antibody levels, which will allow researchers to determine if the vaccine is effective. Antibody levels will be the main indicator, but researchers will also look for coronavirus infections with or without symptoms.
Dr. Wohl said the study was well designed and likely efficient, but asked why the children should only be observed for one year when adults in Moderna's study were observed for two years. He also said he was a little surprised to see the vaccine being tested in children so young so soon.
"Should we first learn what happens to the older children before we go to the really young children?" Asked Dr. Well. Most young children don't get very sick from Covid, although some develop severe inflammatory syndrome that can be life-threatening.
Johnson & Johnson has also announced that it will test its coronavirus vaccine in babies and toddlers, after first testing it in older children.
Pfizer-BioNTech is testing its vaccine in children ages 12-15 and plans to switch to younger groups. The product is already approved for use in the USA from the age of 16.
Last month, AstraZeneca began testing its vaccine in the UK in children 6 years and older.