Pfizer vaccine is 100% effective in preventing COVID-19 in children ages 12 to 15

A teenager being vaccinated.
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The Pfizer-BioNTech vaccine was 100% effective in preventing COVID-19 among children ages 12 to 15 in a phase 3 trial, the companies announced on Wednesday (March 31).

The companies plan to submit the data to the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) "as soon as possible" to expand emergency authorization to this age group, according to a statement posted online. 

The hope is that vaccination of this age group can begin before the start of the next school year, Albert Bourla, Pfizer's chairman and chief executive officer said in the statement. The findings haven't yet been peer-reviewed.

Related: COVID-19 vaccines in use and how they work

The phase 3 clinical trial conducted in the U.S. involved 2,260 participants between the ages of 12 and 15: Half of the kids received the vaccine, and the others received a placebo. During the trial period, 18 cases of COVID-19 occurred in the placebo group and none occurred in the vaccinated group, the company reported.

The company reported that the vaccine triggered levels of neutralizing antibodies one month after the second vaccine dose that was higher than those elicited by participants ages 16 to 25 in a previous analysis. What's more, the vaccine "was well tolerated, with side effects generally consistent with those observed in participants 16 to 25 years of age," according to the statement.

All of the participants will continue to be monitored for two years following their second dose so researchers can analyze long-term protection and safety.

"Across the globe, we are longing for a normal life. This is especially true for our children," Ugur Sahin, CEO and co-founder of BioNTech, said in the statement. "The initial results we have seen in the adolescent studies suggest that children are particularly well protected by vaccination, which is very encouraging given the trends we have seen in recent weeks regarding the spread of the B.1.1.7 UK variant."

Currently, the Pfizer-BioNTech vaccine has emergency approval for those ages 16 and older. The other two vaccines that are being widely distributed in the U.S., Moderna and Johnson and Johnson, have emergency approval for those ages 18 and older. 

Moderna is currently also testing its vaccine in older children, ages 12 to 17, Live Science previously reported. Both Moderna and Pfizer/BioNTech have also begun clinical trials to test their vaccines in even younger children and infants. Johnson & Johnson also has plans to test its single-dose vaccine in children and infants.

Originally published on Live Science.

Yasemin Saplakoglu
Staff Writer

Yasemin is a staff writer at Live Science, covering health, neuroscience and biology. Her work has appeared in Scientific American, Science and the San Jose Mercury News. She has a bachelor's degree in biomedical engineering from the University of Connecticut and a graduate certificate in science communication from the University of California, Santa Cruz.