The hunt for a COVID-19 vaccine for children is only just beginning and that has some American pediatricians worried. Those doctors are concerned they may not know if any vaccine works for young children in time for the next school year. Older adults may be most at risk from the coronavirus, but ending the COVID-19 pandemic will require vaccinating children, too. Last week, drug maker Pfizer received permission to test its vaccine in U.S. children as young as 12 years old. It is one of only a few tests around the world to consider if any of the experimental vaccines made for adults also can protect children. “I just figured the more people they have to do tests on, the quicker they can put out a vaccine and people will be safe and healthy,” said 16-year-old Katelyn Evans. She became the first teenager to get an injection in the Pfizer study at Cincinnati Children’s Hospital in Ohio. Several possible vaccines are in studies in tens of thousands of adults. Scientists hope they will find evidence that some of them are safe and effective enough for widespread use.