WASHINGTON (NEXSTAR) — The U.S. Centers for Disease Control and Prevention has asked state officials to be ready to distribute a potential coronavirus vaccine as soon as October.

According to documents obtained by The New York Times, the CDC has also given states scenarios to help them prepare. The scenarios included prioritization for health care professionals and essential workers in the event the vaccine supply is limited.

Last week, CDC Director Dr. Robert Redfield sent states a letter asking them to waive requirements that might prohibit quick vaccine distribution, according to CNN. The CDC has asked that any restrictions be adjusted by November 1.

“Right now I will say we’re preparing earnestly for what I anticipate will be reality … that there’ll be one or more vaccines available for us in November, December — and we have to figure out how to make sure they’re distributed in a fair and equitable way across the country,” Redfield said while speaking to Yahoo Finance.

Companies preparing vaccines are also working on increasing distribution in the event their product is approved.

Three vaccines are currently in Phase 3 trials in the United States. U.S. Food and Drug Administration Commissioner Dr. Stephen Hahn has said it’s possible the FDA would authoritize an experimental vaccine before large Phase 3 trials have been completed.