By Doina Chiacu and Deena Beasley

WASHINGTON (Reuters) – If Pfizer Inc. submits the positive initial data from its COVID-19 vaccine trial to health regulators as quickly as expected, the U.S. government plans to begin vaccinating Americans in December, Health Secretary Alex Azar said on Tuesday.

Pfizer on Monday said the vaccine it has been developing with German partner BioNTech SE was 90% effective against COVID-19, based on an early look at results from its large, late-stage trial.

The U.S. drugmaker said it expects to have safety data as soon as next week that it needs to apply for emergency use authorization (EUA) with the U.S. Food and Drug Administration.

Upon FDA authorization, the United States would receive about 20 million doses of the Pfizer vaccine per month, Azar said on a call with reporters, noting that HHS could being procuring supplies at the end of this month.

The United States has a $1.95 billion contract for 100 million doses of the Pfizer vaccine – enough to inoculate 50 million people – with an option to acquire 500 million more.

Earlier on Tuesday, Azar said on CNBC that final decisions are subject to a close look at the vaccine efficacy data.

Based on recommendations to the government, it will likely start with inoculations of the elderly in nursing homes and assisted living facilities, healthcare workers and first responders, with a goal to complete those shots by the end of January.

Top U.S. infectious disease expert Anthony Fauci also said in an interview with MSNBC that he expects the doses of the vaccine to be available for certain high priority groups in December.

Azar said he anticipates there will soon be more vaccines to protect against COVID-19 from other companies, including Moderna Inc <MRNA.O>, which is expected to announce interim results of a large trial of its experimental vaccine at the end of the month.

“By the end of March, early April, we expect to have enough for every American who would like to be vaccinated,” Azar told CBNC.

ANTIBODY DRUG DISTRIBUTION

Azar also said the U.S. government would begin distribution of Eli Lilly and Co’s antibody treatment this week, starting first in areas with the highest numbers of hospitalized COVID-19 patients and overall cases.

The treatment, which is administered by infusion, received an EUA on Monday.

“We’ll ensure equitable distribution, and we’ll work tightly with our governors,” Azar said. He said the government will use the same process employed to distribute remdesivir, an antiviral drug from Gilead Sciences Inc used to treat people hospitalized with COVID-19.

According to the Health and Human Services website, the agency will ship more than 79,000 doses of the antibody therapy this week, with the largest number going to Wisconsin, Texas, California, and Illinois.

The United States has purchased 300,000 doses of the treatment for this year and has an option to buy an additional 650,000 doses next year.

Azar said health officials and Eli Lilly were exploring ways to provide the treatment outside of hospitals, including through outpatient infusion centers.

Fauci described the Lilly treatment as “an important first step in the development and distribution of interventions that are given early in the course of disease.”

(Reporting by Doina Chiacu in Washington, Caroline Humer and Carl O’Donnell in New York, Deena Beasley in Los Angeles and Manojna Maddipatla in Bengaluru; Editing by Andrew Heavens, Alexandra Hudson and Bill Berkrot)