A coronavirus vaccine may be delivered to high-risk populations in the United States as early as late December, or by early January, according to Anthony Fauci, M.D., the United State’s chief infectious disease expert.

The forecast is based on the latest projections from vaccine makers Moderna and Pfizer, Fauci said in a live Twitter and Facebook conversation on Thursday. 

The two companies are working with the federal government as part of its Operation Warp Speed COVID vaccine acceleration program. Moderna on Thursday announced that it will be ready to release data from a late-stage vaccine trial in November. Pfizer has said it will do so after the presidential election. Both companies are already producing doses of the vaccines as part of a supply agreement with the U.S. government in anticipation of future drug approval.

“The first interim look [at trial results] should be, we hope, within the next few weeks,” Fauci said, according to a Reuters report.

U.S. health officials last week reinforced the message that long-term care residents and staff members are likely Phase 1 recipients of COVID vaccines if initial supplies are limited.

Dr. Fauci is the director of the National Institute of Allergy and Infectious Diseases.