"I think by the end of the summer, I think we'll be in a different position than we are now," said President Joe Biden recently.
About 2.4 million people in the United States are now receiving COVID-19 vaccinations daily. Experts including Dr. Anthony Fauci have estimate between 70% to 85% of the US population needs to be immune to the virus -- through vaccination or previous infection -- to control its spread.
"If we get partial immunity the pandemic will end, but it's very likely the virus will continue every winter time, like we have with flu viruses," said Dr. Robert Citronberg of Advocate Aurora Health.
Dr. Citronberg said herd immunity already exists in several parts of the country, with large majorities of those at highest risk for severe outcomes already vaccinated. And some vaccination is certainly better than none.
"Even if we have 40% or 50% vaccination in any community, it is still so much better than not having any. Because it still protects people, just not as much," he explained. "So it should still be the goal, the long term goal, to achieve national or global herd immunity."
One medical expert thinks the nation may not reach herd immunity this year if more people can't be persuaded to get a shot.
"What I really worry about is that those people who are already on the fence don't get vaccinated (and) we don't reach herd immunity come the fall," CNN medical analyst Dr. Leana Wen told CNN. "And then with the winter...we have a big resurgence, maybe we have variants coming in from other countries, and we could start this whole process all over again and have another huge pandemic come the winter."
So far, more than 44% of the population has received at least one COVID-19 vaccine dose and more than 31% is fully vaccinated, according to data from the Centers for Disease Control and Prevention.
"It's going to take us that much longer to get back to life as normal, to stop having to wear masks for our protection, if people don't get vaccinated and we don't have equitable distribution of vaccines," infectious diseases specialist Dr. Celine Gounder told CNN on Sunday.
Some experts think driving down infections will be good enough, even if herd immunity isn't reached.
While it would be unfortunate for the United States to not reach herd immunity against COVID-19, most people will still be able to get back to their pre-pandemic lives if case numbers continue to fall, Dr. Ashish Jha, dean of the Brown University School of Health, told CNN on Monday.
"We may not get to zero, we probably won't," Jha said. "But if we can get the infections at very low levels, most of us can get back to our lives in normal ways. I think we can probably live with that."
For the ongoing local, state and federal efforts to get more shots into Americans' arms, now comes the hard part: reaching audiences that weren't as eager to get vaccinated in the past few months or who may not have had access to a shot.
"We need to be ... innovative around both culturally competent education and be thoughtful about where the holes are and where we can get shots in people's arms," infectious diseases expert Dr. Mati Hlatshwayo Davis told CNN over the weekend.
'Make it really easy' to get vaccinated,' doctor says
New strategies to increase vaccinations must be tried, such as closing mass vaccination centers and distributing vaccine to more localized venues such as doctors' offices, churches, schools and workplaces, Wen said.
The government should "make it really easy" for people to get vaccinated, Wen said, especially Americans who aren't really vaccine hesitant but just can't find the time because jobs and family responsibilities.
Also, the social upside of vaccination should be emphasized.
"I think we should do just like people did with vaccine selfies," Wen said. "I think we need selfies of people now going to bars and restaurants with other vaccinated people to show what a return to 2019 pre-pandemic life could really look like."
One doctor told CNN on Sunday he's worried officials haven't offered strong enough incentives for some Americans to get vaccinated -- including younger Americans.
"What I worry about mostly are the young people," primary care physician Dr. Saju Mathew said. "I see them every day, pretty much, at work."
The CDC issued new guidance last week saying fully vaccinated people can unmask at small outdoor gatherings or when dining outside with friends from multiple households -- activities the agency said unvaccinated people still need to wear a mask for.
But the guidelines are too cautious, Mathew said.
"I think that the CDC missed an opportunity to say, 'Listen, we can return to pre-pandemic lives, and you can do more if you're vaccinated,'" Mathew said. "So, I think, when the science is there with positive news, we must share that and motivate people to get vaccinated."
Everyone 16 and older is currently eligible for a COVID-19 vaccine in the US. But polling data shows younger Americans are least likely to get a shot.
But 36% of adults under the age of 35 say they don't plan on getting one, a recent Quinnipiac University poll found.
That's particularly worrisome for several reasons.
Unvaccinated young Americans have helped fuel case increases across the US -- including in several states last month. At that time, CDC Director Dr. Rochelle Walensky warned that infections and hospitalizations were going up, predominantly among younger adults who hadn't been vaccinated.
And in places like Michigan, which battled a violent spring surge, officials reported last month they were seeing younger and healthier COVID-19 patients in hospitals, hit hard by more contagious variants that have been circulating in the US.
'A ton of young people' testing positive
Last week, West Virginia Gov. Jim Justice said the state was offering a $100 savings bond to residents 16 to 35 who get a shot, in a push to get more younger residents vaccinated.
The median age of residents testing positive for the virus has dropped, the governor said.
"When it recently came down to 44 years of age, we thought, 'Uh oh. We've got a problem. We need to get our young people vaccinated,'" Justice said in a statement. "But now we're down to 34, and that means we've got a ton of young people that are testing positive."
The governor warned young people that they should be concerned -- both about transmitting the virus and about the long-term effects that may linger long past their infection.
In Oregon, where the governor recently tightened restrictions for some counties amid a surge in new cases and hospitalizations, another warning for young residents.
"The overwhelming majority of our new COVID-19 cases are from people who have not yet been vaccinated," Gov. Kate Brown said in a statement. "Younger, unvaccinated Oregonians are now showing up in our hospitals with severe cases of COVID-19."
But in Florida, Gov. Ron DeSantis signed an executive order Monday suspending the remaining power of local governments to implement or enforce COVID-19 restrictions.
"I think that's the evidence-based thing to do. I think folks that are saying they need to be policing people at this point, if you are saying that, you really are saying you don't believe in the vaccines, you don't believe in the data, you don't believe in the science," DeSantis said at a news conference in St. Petersburg.
ABC OTV stations contributed to this report
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