Moderna says its Covid vaccine is 100% effective

May 26, 2021: -On Tuesday, Moderna said its Covid-19 vaccine was 100% effective in a study of adolescents ages 12 to 17, making it the second shot behind Pfizer’s to demonstrate high efficacy in younger age groups.

The company said it plans to ask the Food and Drug Administration to expand the emergency use of its Covid vaccine for teens early next month. If approved, it would likely dramatically expand the number of shots available to middle and high school students ahead of the next school year. Pfizer and German partner BioNTech were cleared to use their vaccine for 12- to 15-year-olds earlier this month.

“We are encouraged that mRNA-1273 was highly effective at preventing COVID-19 in adolescents,” Moderna CEO Stephane Bancel said in a press release. “We remain committed to doing our part to help end the COVID-19 pandemic.”

The phase 2/3 study the company is citing on Tuesday included over 3,700 adolescents. According to the company, no cases of Covid were observed in participants who received two doses of the vaccine, while four points were observed in the placebo group.

No significant safety concerns have been identified, and side effects generally are consistent with those seen in an earlier trial of adults, the company said. The most common side effects after the second dose were headache, fatigue, muscle pain, and chills, Moderna said.

On Tuesday, the company said the shot was shown in the trial to be 93% effective after one dose. Because children are less likely to get seriously ill, Moderna used the Centers for Disease Control and Prevention’s definition of Covid-19 to calculate that figure. It requires only one symptom and a positive Covid test.

U.S. regulators are expected to grant Moderna’s request for use in teens. The approval process could take about a month, just in time for some summer activities and fall classes, if Moderna submits the data by early June. Pfizer and BioNTech requested expanded use of their shot in adolescents on April 9, for example, and were authorized by the FDA on May 10.

Children make up around 20% of the total U.S. population, according to government data. Some 70% to 85% of the U.S. population needs to be vaccinated against Covid to achieve herd immunity, medical experts say, and some adults may refuse to get the shots. Though more experts now say herd immunity is looking increasingly unlikely as variants spread.

Vaccinating kids may also hasten the return of in-person learning and greenlight after-school extracurricular activities such as sports, art, and other in-person activities, health experts say.