Pfizer is asking the Federal Drug Administration to approve its vaccine for use in 12- to 15-year-olds. If the FDA moves forward with the request, all teenagers can be vaccinated before the beginning of the next school year, potentially moving the nation closer to herd immunity. “Pending regulatory decision, our hope is to make this vaccine available to the 12-15-year-old age group before the start of the 2021 school year,” Pfizer said in a statement. Last week, the company announced that its recent clinical trial involving 2,200 individuals shows that the vaccines are 100 percent effective and safe in younger teens. During the trial, half of the 12- to 15-year-olds were given the vaccine two weeks apart, and the other half were given placebo shots. Eighteen of those who received the placebo tested positive for the coronavirus, while none of the vaccine recipients did. Pfizer’s vaccine was initially approved in December for use in teenagers 16 and older. Pfizer intends to make similar requests to expand the age range in other countries, according to a statement on Twitter. The company is also researching the vaccine’s effect on children 11 and younger.