When will kids get a vaccine?

Measles. Mumps. Rubella. Diptheria. Polio. Whooping Cough. These are childhood diseases that are no longer terrifying, thanks to vaccines. Soon there will be a new addition to the list: COVID-19. On Wednesday, Pfizer launched its test of a childhood vaccine in a pair of 9-year-old twin girls at Duke University in North Carolina. Stanford University will also participate in that trial, which will assess the vaccine in children between the ages of six months to 11 years. Studies are already underway of both the Pfizer and Moderna vaccines in adolescents ages 12 years to 15 years.

By late April or early May, scientists expect to get initial results of vaccine tests in adolescents. It’ll be later — the second half of the year, according to Pfizer — to obtain data in younger children.

“We want to protect our children,” said Stanford pediatrician and infectious disease expert Dr. Yvonne Maldonado, who will lead Stanford’s trial of the Pfizer vaccine in children later this spring.

“And we want to protect the general population,” she added. With children representing more than one-fifth of U.S. residents, “if you can vaccinate at least even a good proportion of kids, that will prevent transmission.”

Will the vaccines get the go-ahead in time for the next school year? That’s not known. While the federal authorization process will be shorter than it was for adult vaccines, manufacturers must still prove safety and efficacy.