(CNN) -- Dr. Anthony Fauci said it could be the end of 2021 before life gets back to how it was before Covid-19.
"If you're talking about getting back to a degree of normality which resembles where we were prior to Covid, it's going to be well into 2021, maybe even towards the end of 2021," Fauci said Friday.
A vaccine will help, but there are caveats, Fauci said in a series of interviews Friday.
"By the time you mobilize the distribution of the vaccinations, and you get the majority, or more, of the population vaccinated and protected, that's likely not going to happen to the mid or end of 2021," he told MSNBC's Andrea Mitchell.
One stumbling block -- keeping the vaccines cold. Most of the experimental coronavirus vaccines must be kept frozen.
Speaking during a Friends of the Global Fight webinar earlier on Friday, Fauci said, "One of the things that's always an issue is the cold storage issue, and the 'cold chain' that is so often required."
Plus, people are not always doing what they should do to control the spread of the virus, even now, Fauci said.
"When you're dealing with a situation that requires behavioral change, we in the United States have a significant issue that I'm very disappointed in," Fauci said during the webinar.
"It was stunning to me ... that in some states and cities and counties, you would see television clips of people crowded indoors at bars, which is a superspreading event if you ever saw it."
Young people may think they are not going to get dangerously ill, and get careless, Fauci said.
"But what they forget is their societal responsibility to not propagate the outbreak because if they get infected, they're likely going to infect someone else who then might infect someone who really is vulnerable and will have a serious severe consequence."
And people are spreading misinformation, making the virus even harder to fight.
"The one thing that bothers me is the amount of things that aren't evidence-based, and we've seen examples of that in the United States like claims that certain drugs have a great positive effect when there's no scientific evidence whatsoever that they have a positive effect," Fauci said.
"And yet it gets ingrained and I and my colleagues have to spend a lot of time trying to debunk that. And you're in the middle of a pandemic and you're trying hard to address all the appropriate issues, it is truly a waste of time to have to debunk nonsense."
Fauci also cautioned that just because coronaviruses are in the spotlight, people should not forget the flu.
"The one thing I've learned throughout the years is don't put anything past the flu -- don't take anything for granted," he said during the MSNBC interview.
There "a hint of potential good news" when it comes to flu season. In Australia, where the flu season just ended, "They have had the lightest flu season in memory -- which most people think is because they're doing things to prevent SARS-CoV2 infection with masks, distancing, avoiding crowds, outdoor more than indoor. That what they've done as a secondary offshoot of that is they brought down the level of influenza cases, very, very low," he said.
He added that if Americans can do this, he's optimistic the country will have a light flu season too.