On Wednesday morning, Pfizer reported that its coronavirus vaccine, which has been authorized for Americans who are 16 years and older, is 100% effective in children ages 12 to 15. This encouraging news comes as experts warn of another resurgence of coronavirus cases, mostly driven by the younger population.

As of March 30, 50% of all seniors in the United States have been fully vaccinated, according to Andy Slavitt, a White House senior advisor, via Twitter.

“We share the urgency to expand the authorization of our vaccine to use in younger populations and are encouraged by the clinical trial data from adolescents between the ages of 12 and 15,” said Albert Bourla, the CEO of Pfizer.

The trial enrolled 2,260 adolescents 12 to 15 years of age in the U.S. No symptomatic infections were found among children aged 12 to 15 who received the vaccine in a recent clinical trial, compared to 18 cases of COVID-19 in the placebo group.

In addition to zero reported cases, the adolescents reported robust antibody responses, even exceeding those reported in the trial of vaccinated 16 to 25-year-old participants in an earlier analysis, according to Pfizer.

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Vaccination efforts are continuing to stay strong throughout the country. As of April 1, 30% of the country has received at least one vaccination dose and 16.9% of the country has been fully vaccinated, according to a tracker by the Centers for Disease and Prevention. To kick off the month of April, the U.S. reported over 3.3 million inoculations in one day, close to its single-day record.

Pfizer has already begun clinical trials to test the efficacy of their vaccine in children ages 5 to 11 and plans to initiate the 2 to 5-year-old cohort next week.

“Across the globe, we are longing for a normal life,” said Ugur Sahin, the CEO of BioNTech. “This is especially true for our children. 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 … UK variant.”

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