The first doses of a COVID-19 vaccine could be administered by mid-December, an Operation Warp Speed advisor said.

Dr. Moncef Slaoui, Warp Speed's chief scientific adviser, said in an interview with NBC News that as soon as the approval has been given by the U.S. Food and Drug Administration (FDA) to a COVID-19 vaccine candidate, Americans can start getting inoculated.

Slaoui noted that he expects a vaccine approval on "the 11th or the 12th of December." He added that "within 24 hours from the approval," the COVID-19 vaccine would be moved to areas stated by each U.S. state.

The chief advisor said the plan is to get the vaccines to immunization sites within 24 hours of approval so that people may get it a day or two after shipping.

Operation Warp Speed may start the largest effort to immunize people in U.S. history by mid-December if the FDA approvals push through soon, said a Reuters report.

Warp Speed Official Predicts 'Herd Immunity' by May

Slaoui also predicted that the life of U.S. residents could get back to normal living by mid-2021, said a New York Post report.

He noted that by that time, some 70 percent or so of the country's population would already be immunized, and "true herd immunity" can take place.

"Most people need to be immunized before we can go back to a normal life," he added.

Slaoui predicts herd immunity will help the government's effort in fighting the virus by May "or something like that."

People's negative perception of the vaccine, once it does come out, along with the people's acceptance, will be critical in helping the government's effort in stopping the spread, said Slaoui.

Who Gets the COVID-19 Vaccine First?

Guidance from the Advisory Committee on Immunization Practices and Centers for Disease Control and Prevention will determine who gets priority in the first COVID-19 vaccine doses.

But Slaoui thinks health care workers will be part of the first to get doses, alongside first-line workers, individuals who are at very high risk, the elderly, people with comorbidities.

Priorities within each state had already been identified, and local health departments have determined where they want the vaccines to go.

Some vaccines have recently shown promising results. Some have already sought FDA approval, while others are just waiting for data from late-stage trials, claiming at least 90 percent protection against the virus.

One of those candidates is Pfizer and BioNTech's vaccine candidate, which said it was 95 percent effective against the coronavirus. The company also announced that it applied for emergency use approval, or EUA, from the FDA on Friday.

Another vaccine candidate is from the biotech firm Moderna that also claimed it was 95 percent effective. It will also seek a EUA in the coming weeks.

While President Donald Trump's administration tries to roll out vaccines across the U.S., the campaign of former vice president Joe Biden has been hoping for a normal transition of government before January.

But it has been blocked by Trump through his legal challenges of the election in several states.

Slaoui was hoping that if a transition gets certified by the General Services Administration, it will be smooth not to derail the vaccination effort.