(Bloomberg) -- President Joe Biden urged more Americans to get vaccinated, saying that the coronavirus is only raging among those who have not received their shots and that those under 12 years old will be able to get inoculated “soon.”

“We have a pandemic for those who haven’t gotten the vaccination,” Biden said Wednesday night during a CNN town hall in Cincinnati. “It’s that basic, it’s that simple,”

“If you’re vaccinated,” the president added, “you’re not going to die.”

The president also said the U.S. Centers for Disease Control and Prevention would likely recommend children under age 12 wear a mask in school. He said that vaccine approval for those children is coming “soon,” but would not predict exactly when. He said he would not pressure government scientists to authorize them before they are ready.

“I do not tell any scientists what they should do,” Biden said. “I do not interfere. They’re doing their examinations now. They’re testing now.”

The delta variant now accounts for more than 80% of U.S. cases, posing a fresh challenge for the Biden administration, which has so far been widely praised for its handling of the pandemic and distribution of vaccines. Officials warn that the continued spread of the delta variant could undo some of the gains against the virus and jeopardize the economic recovery.

The country’s decline in coronavirus cases bottomed out in June but the spread of variants has causes rates to surge, especially in states with low vaccination rates. There were more than 44,700 cases recorded on Tuesday in the U.S., up dramatically from last month’s low, with states like Tennessee and Alabama showing surging cases.

Most hospitalizations and deaths from the delta variant have occurred among unvaccinated people. Yet there have also been so-called breakthrough Covid infections of fully vaccinated people, including multiple aides on Capitol Hill and at the White House. Jen Psaki, Biden’s press secretary, on Tuesday urged vigilance but said the administration is not preparing to tighten nationwide guidance on mask wearing.

The White House is redoubling its efforts to persuade Americans to get vaccinated. And now a growing number of Republicans are urging people to get the shots -- a reversal of skeptical messaging among many conservatives about the vaccines that has swayed many of their supporters not to get them.

A study released Tuesday showed that Johnson & Johnson’s single-dose vaccine produced relatively low levels of antibodies against the delta variant. Two-dose messenger RNA vaccines from Pfizer Inc. and Moderna Inc. also produced fewer antibodies against the strain but the reduction was less dramatic, according to the study.

©2021 Bloomberg L.P.