CNN  — 

While the pace of Covid-19 vaccinations may be slowing in the US, experts are optimistic about where the country will be in just a matter of weeks.

“This summer is going to seem so much closer to normal than we’ve had in a very long time,” Dr. Jonathan Reiner, professor of medicine and surgery at George Washington University, told CNN on Sunday. “The key statistic to think about is … what percentage of the adult population has received at least one vaccination.”

Roughly 58% of US adults – and nearly 46% of the country’s total population – have received at least one Covid-19 vaccine dose, according to data from the Centers for Disease Control and Prevention. More than 34% of the US population is fully vaccinated, CDC data shows.

Once the country climbs above that 60% mark of American adults with at least one dose, Reiner says it’s likely we’ll begin to see Covid-19 numbers plummet.

“I expect during the month of May we will see daily cases drop dramatically and deaths finally drop to quite low numbers,” he said.

Other experts also have predicted life will start to look more normal, even if the US hasn’t yet reached “herd immunity” – when enough people are immune to the virus, either through vaccination or previous infection, to suppress its spread.

Dr. Anthony Fauci has estimated about 70-85% of people need to be immune for the country to reach a “total blanket of protection,” he told CNN late last month.

“However, even before you get to that, as you get more and more people vaccinated, you will reach a point … where you’ll start to see the number of cases going down dramatically,” Fauci said at the time.

Pedestrians pass in front of Covid-19 vaccination site signs in New York on April 30.

‘We are turning the corner’

That’s down from where we were in January, when the US hit a seven-day average peak of more than 251,000 daily Covid-19 cases and a seven-day average of more than 3,400 daily Covid-19 deaths.

“I would say we are turning the corner,” White House Covid-19 Response Coordinator Jeffrey Zients told CNN on Sunday, but stressed it’s important that Americans continue to get vaccinated.

Last week, President Joe Biden set a new goal of administering at least one Covid-19 vaccine dose to 70% of American adults by July 4. That goal is inching closer to realization now that the US Food and Drug Administration (FDA) expanded the emergency use authorization for Pfizer’s Covid-19 vaccine Monday to include children ages 12 to 15.

“It was a relatively straightforward decision,” Dr. Peter Marks, director of FDA’s Center for Biologics Evaluation and Research, the arm of the FDA that regulates vaccines, told reporters Monday evening.

This is the first Covid-19 vaccine in the United States authorized for use in younger teenagers and adolescents. The vaccine was previously authorized for people 16 and older.

Covid-19 vaccines from Moderna and Johnson & Johnson are still authorized for use only with people 18 and older.

Expanding authorization to children 12 to 15 opens Covid-19 vaccination to another 5% of the US population – nearly 17 million more people. The expanded authorization means 85% of the US population is eligible to receive a Covid-19 vaccine.

The CDC’s Advisory Committee on Immunization Practices is scheduled to meet Wednesday to advise the CDC on whether to recommend use of the vaccine in this age group. CDC Director Dr. Rochelle Walensky will then decide whether the agency will recommend the vaccine’s use in the new group.

Vaccinations for 12-to-15-year-olds are not expected to begin until after that recommendation, but could begin as soon as Thursday, FDA officials said Monday.

The Biden administration has said it will quickly mobilize to ready vaccinations for 12-to-15-year-olds through the federal pharmacy program, pediatricians and family doctors.

Pfizer said last week it expects to ask the FDA in September for emergency use authorization for its Covid-19 vaccine for children ages 2 to 11. Its vaccine safety and efficacy study in children ages 6 months to 11 years old is ongoing.

Officials still face uphill battle in vaccinations

But experts say administering more doses will now be an uphill battle, as officials try to reach audiences who aren’t as eager for a shot or who may still have challenges with access.

“We’ve got a path ahead of us, which will involve getting people even easier access to the vaccine, making sure that people build their confidence, those who have questions about the vaccines, that we answer their questions. And making sure that we do … this in a fair and equitable way,” Zients said.

The city of Los Angeles most recently unveiled new efforts to make Covid-19 vaccines more accessible, announcing it will offer vaccinations without appointments at all of its sites starting Monday and will also open two more night vaccination clinics.

“We stand at a critical juncture in our fight to end this pandemic, and our City will keep doing everything possible to knock down barriers to vaccine access,” Mayor Eric Garcetti said in a statement.

Some experts say they are concerned about what could happen if the country doesn’t vaccinate enough Americans. It’s unlikely the US will see a Covid-19 surge comparable to those of last fall and winter if enough people are vaccinated, Fauci said in an interview with NBC News’ “Meet the Press.”

“You may see blips but if we handle them well, it is unlikely that you’ll see the kind of surge that we saw in the late fall and the early winter,” Fauci said.

The more Americans vaccinated, the less likely it will be that once the fall and winter roll around, the US will see another significant surge, he added.

“That’s the reason why vaccinations are so important.”

Time to rethink indoor mask mandates, officials say

For now, the risk of Covid-19 has been substantially reduced with the help of vaccinations and it’s time for some parts of the country to start lifting indoor mask requirements, Dr. Scott Gottlieb, former FDA commissioner, said.

“Covid won’t disappear, we’re going to have to learn to live with it,” he said on CBS’ “Face the Nation” on Sunday. “I think we’re at the point in time where we can start lifting these ordinances … and people have to take precautions based on their individual risk … and decide whether or not they’re going to avoid crowds or wear masks based on their circumstances.”

He added officials shouldn’t be putting limits on outdoor gatherings anymore, either, and should instead be encouraging people to spend more time outdoors.

“The public has to trust that public health officials are going to lift these restrictions as quickly as they put them in place as the conditions improve,” he added.

Fauci also told ABC News it may be time to rethink indoor mask mandates.

“We do need to start being more liberal as we get more people vaccinated,” Fauci said Sunday. But he added the country still has a long way to go when it comes to bringing down its Covid-19 cases.

“When that gets lower, the risk of any infection, indoor or outdoor, diminishes dramatically.”

CNN’s Naomi Thomas, Lauren Mascarenhas, Deidre McPhillips and Keith Allen contributed to this report.