HARRISBURG, Pa. — Pennsylvania is facing a temporary shortage of booster shots of the Moderna vaccine because providers inadvertently used them as first doses, setting back the state’s already stumbling vaccine rollout.

The error could mean more than 100,000 people will need appointments rescheduled, state health officials said Wednesday.

Acting state health secretary Alison Beam said between 30,000 and 60,000 people who need the booster shot will have to wait one to two more weeks. Another 30,000 to 55,000 of the initial dose of the Moderna vaccine will also have to delayed.

The second-dose shortage does not affect the Pfizer vaccine.

Second doses of the two-shot Pfizer and Moderna vaccines are typically administered 21 and 28 days apart, respectively, but the U.S. Centers for Disease Control and Prevention recently updated its guidance to allow the time between shots to be delayed up to six weeks.