For months, people have wondered when life will return to "normal" during the pandemic.

Microsoft co-founder Bill Gates has an estimation. With promising vaccines and therapeutic treatments on the horizon, Gates said that the United States could be on its way back to normal by spring 2021, during an interview with NBC's "TODAY" on Thursday.

The current state of the pandemic in the U.S., however, is troubling. There are currently more than 100,000 people hospitalized for Covid in the U.S., and more than 13.93 million total cases.

"The next four or five months actually look pretty grim, unless we can really double down on our behavior," Gates told Savannah Guthrie.

"The most impactful thing" people can do right now to reduce further spread and end the pandemic, is to follow what we've been told to do all along, Gates said. For example, "associating with people less, [and] wearing a mask wherever you might be exposed to someone outside your household," he said.

Advancements in treatment tools, such as monoclonal antibody treatments (which work by mimicking the immune system's ability to fight off viruses), and the rollout of "amazing vaccines" will also help, Gates said. "By the spring, those numbers will be big enough that, certainly in the United States, it'll start to change for us dramatically, and we'll be headed headed back to normal."

Vaccines are close to approval. Drug makers Pfizer and Moderna have filed for emergency use authorization for Covid vaccines from the Food and Drug Administration. And the Pfizer vaccine was cleared for emergency use in the U.K. on Wednesday, and is expected to roll out out next week.

New York Gov. Andrew Cuomo said Wednesday that the state expects enough doses by Dec. 15 to vaccinate 170,000 people.

Dr. Anthony Fauci, the nation's leading expert on infectious diseases, said that by April, healthy young people with no underlying conditions will be able to "walk in to a CVS or to a Walgreens and get vaccinated," during an interview with Facebook CEO Mark Zuckerberg Nov. 30.

Lt. Gen. Paul Ostrowski (Ret.), who is Operation Warp Speed's director of supply production and distribution, said that everyone who wants to get vaccinated should be able to do so by June, during an interview with CNBC's "The News with Shepard Smith" on Wednesday.

Gates said that timeline "should be achievable" with the right messaging to the public.

Fauci has said that 75%-85% of Americans need to get the vaccine in order to achieve herd immunity. According to a Gallup survey conducted Oct. 19-Nov. 1, 58% of Americans say they would get a Covid vaccine.

Former Presidents Barack Obama, George W. Bush and Bill Clinton have each said they would take the vaccine and would publicize it on camera to build public confidence.

Gates added that he's "hopeful" that people who might be ambivalent about taking the Covid vaccine will be encouraged by "more data that that says a lot of people are having a good experience, and it is helping them not die."

Of course, a vaccine won't instantly eliminate the need for prevention measures such as wearing masks and social distancing, Fauci told CNN's Jake Tapper on "State of the Union" on Nov. 15. It could take months for the preventative effect of vaccine to kick in.

"If you want to be part of the solution, get vaccinated," Fauci said during the Facebook interview.

Check out: Bill Gates on his WFH schedule during the pandemic, including what he likes about it

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