A total of 20 million Americans could be vaccinated with Pfizer's COVID-19 vaccine before the end of the year, according to a top official involved in the government's vaccine initiative.

Moncef Slaoui, the chief advisor to Operation Warp Speed, discussed the possible availability of the COVID-19 vaccine over the next few months during a White House press briefing on Friday.

According to Slaoui, the number could increase to between 25 and 30 million people by January next year.

By the end of February, Slaoui forecasted that around 70 million to 80 million people in the U.S. could be vaccinated against the virus. That is as much as a quarter of the country's population, according to a Business Insider report.

"The vaccines and the therapeutics that we have helped develop and accelerate will be judged independently and, if approved, should be used by all in the population because I believe vaccination is likely to be the cornerstone among all the other measures that we have to take to help us really control this pandemic," Slaoui said in a USA Today report.

National Institute of Allergy and Infectious Diseases Director Dr. Anthony Fauci and Health and Human Services Secretary Alex Azar had earlier said that the COVID-19 vaccine could be widely available to the public as early as April 2021.

The limited vaccine supplies would initially be given to frontline workers and people at high risk of becoming seriously ill if infected, such as the elderly with several pre-existing health conditions.

Related story: Health Experts Raise Safety Concerns for Pfizer's COVID-19 Vaccine

The details of the distribution plan will be finalized by an advisory group of the Centers for Disease Control and Prevention.

Pfizer plans to apply for an emergency use approval from the U.S. Food and Drug Administration (FDA) next week.

If it receives a go-signal, the company will produce around 50 million vaccine doses by the end of the year and 1.3 billion in 2021. Pfizer's vaccine would need people to take two shots administered three weeks apart.

Pfizer is not part of the Operation Warp Speed program, and it did not receive funding from the government, according to a CNET report.

COVID-19 Related Restrictions

Several states have imposed new COVID-19 related restrictions as new cases rise rapidly across the country.

Oregon Governor Kate Brown on Friday announced a two-week "freeze" in the state. It will take effect on Nov. 18.

During this freeze, restaurants and bars will have to go back to take-out service only. Earlier, they were allowed to have limited indoor seating.

Indoor recreation centers such as gyms, museums, and theaters will have to close again, including zoos and gardens.

Grocery stores, on the other hand, will be limited to a maximum capacity of 75 percent. The governor also urged the public to opt for curbside pickup service when possible.

Brown said they must take necessary measures to flatten the curve now to "give Oregonians a fighting chance." According to Brown, Multnomah County in Portland will be in the freeze for at least four weeks.

Chicago Mayor Lori Lightfoot announced a stay-at-home advisory order set to take effect beginning on Monday.

The mayor advised city residents to avoid unnecessary travel and stay home unless it is essential to go out. Lightfoot also urged residents to avoid having guests over and cancel Thanksgiving plans.

Meanwhile, New Mexico Governor Michelle Lujan Grisham imposed a two-week shutdown to curb the spread of COVID-19, while governors of Vermont, Virginia, and West Virginia also released additional COVID-19 related restrictions.

The U.S. has already reported more than 10.6 million cases and 242,900 deaths.