In a major policy shift, federal health officials anticipate the shots will be made available to adults 65 and older as well as children and younger adults who have one or more risk factors that make them more vulnerable to severe COVID-19.

The Trump administration said Tuesday it will limit approval for seasonal COVID-19 shots to seniors and others at high risk pending more data on everyone else — raising questions about whether some people who want a vaccine this fall will be able to get one.

The U.S. Food and Drug Administration on Tuesday said it plans to require new clinical trials for approval of annual COVID-19 boosters for healthy Americans under age 65, effectively limiting them to older adults and those at risk of developing severe illness.