Lower Dose of Pfizer COVID Vaccine Works Well in Young Children, Company Says

MONDAY, Sept. 20, 2021 (HealthDay News) -- A smaller dose of Pfizer's coronavirus vaccine safely triggers a strong immune response in children as young as 5, the company announced Monday morning.

"Over the past nine months, hundreds of millions of people ages 12 and older from around the world have received our COVID-19 vaccine. We are eager to extend the protection afforded by the vaccine to this younger population, subject to regulatory authorization, especially as we track the spread of the Delta variant and the substantial threat it poses to children," Pfizer Chairman and CEO Albert Bourla said in a statement.

"Since July, pediatric cases of COVID-19 have risen by about 240 percent in the U.S. -- underscoring the public health need for vaccination," Bourla added. "These trial results provide a strong foundation for seeking authorization of our vaccine for children 5 to 11 years old, and we plan to submit them to the FDA and other regulators with urgency."

The finding, which will likely come as welcome news to many parents and pediatricians, is a crucial step toward Pfizer's two-shot regimen becoming available for younger school-aged children as early as Halloween, the Washington Post reported. The pediatric dose used in the trial was one-third the strength of the adult shots.

With coronavirus cases soaring among children as the school year gets underway, pediatricians have been flooded with requests to bend the rules and give children a shot now, the Post reported. The new data seems likely to intensify that pressure, even though Pfizer's existing vaccine is triple the dose tested in the trial.

"No one should really be freelancing — they should wait for the appropriate approval and recommendations to decide how best to manage their own children's circumstances," William Gruber, Pfizer's senior vice president of vaccine clinical research and development, told the Post, explaining that younger children tend to have more "exuberant" immune responses to vaccines than older people do.

"Nature has equipped us, particularly when we are young, to respond very well to an assortment of things we will encounter in nature — and we will use vaccines to accelerate that process and really improve on nature," Gruber added.

Among 12- to 17-year-olds eligible for the Pfizer shot since May, only about half have received at least one dose, according to the American Academy of Pediatrics. More than 5 million cases of COVID-19, the illness caused by the coronavirus, have been reported among children and teens, causing 20,000 hospitalizations and 460 deaths since the start of the pandemic. As children have returned to classrooms, many families and schools have been navigating disruptive quarantines and divisive masking policies.

In July, the FDA asked Pfizer and Moderna to increase the size of their pediatric trials to ensure the safety data was robust, the Post reported. There were nearly 2,300 children between the ages of 5 and 11 in Pfizer's trial, two-thirds of whom received the vaccine. The rest received saline shots.

The trial showed that children who received the vaccine had immune responses similar to those seen in teens and young adults, according to Pfizer. Two shots of a 10-microgram dose, spaced three weeks apart, were well-tolerated.

Gruber said there appeared to be less fever and fewer chills among younger children than in a comparison group of 16- to 25-year-olds, bolstering the company's confidence that it had found the right dose.

Pfizer is seeking emergency use authorization for the pediatric vaccine dose as it continues to gather data to support full approval in children. Data on children younger than 5 is expected by the end of the year, the Post reported. Moderna is also conducting a trial in children as young as six months.

More information

Visit the U.S. Centers for Disease Control and Prevention for more on COVID vaccines.