The highly contagious Delta COVID variant quickly spreading through the U.S. may force schools to double down on mitigation measures in order to reopen safely later this summer and into the fall, health experts say.

It’s “one of the most dangerous time periods [in the pandemic] for people who aren’t vaccinated,” Taylor Nelson, a University of Missouri medical doctor specializing in infectious disease, told The 74. That includes large numbers of young people, she said.

The Delta variant now accounts for about 20 percent of all new U.S. cases, up from about 10 percent two weeks ago, and has led to surges in youth infections abroad.

In England, where the academic year runs until mid-July, a quarter of a million children missed school last week due to testing positive for the virus, self-isolation, or school closures — marking the most disrupted week of learning since the country fully reopened classrooms in March.

Israel, which has led all countries in its vaccination push but has only immunized 2 to 4 percent of 12- to 15-year-olds, saw the number of COVID patients in its education system triple in the past week.

People who have received both vaccine doses have a high level of protection against the new mutation, doctors say. But because youth under 12 are not yet eligible to receive COVID shots, and with immunization rates lagging among adolescents, Joshua Petrie, professor of epidemiology at the University of Michigan, worries that the rise of the Delta variant could elevate the risk for unvaccinated youth.

“Kids are probably the group now that are most susceptible to infection,” he told The 74.

The Food and Drug Administration is expected to expand their emergency use authorization of COVID-19 vaccines to children in the fall of 2021 or early in 2022.

Read the full article about the Delta COVID variant by Asher Lehrer-Small at The 74.