President Biden on Tuesday pleaded with Americans to get vaccinated against COVID-19 as the White House signaled a shift toward grassroots tactics to reach those who have yet to get a shot.

Biden, who just days earlier hosted more than a thousand people at the White House for an outdoor Independence Day gathering, cautioned against getting overconfident in the fight against the coronavirus pandemic as the delta variant contributes to rising case counts in less vaccinated parts of the country.

“Our fight against this virus is not over,” Biden said in prepared remarks delivered from the White House. “Right now, as I speak to you, millions of Americans are still unvaccinated and unprotected. And because of that, their communities are at risk. Their friends are at risk, the people that they care about are at risk. This is an even bigger concern because of the delta variant.”

The president laid out a series of steps his administration is taking to make the vaccine more accessible, with a focus on getting the shot to young people in particular. The White House coronavirus response team is planning to direct more vaccines to doctors’ offices and pediatricians so that individuals, specifically those ages 12-18, can have access to the shots.

Biden also highlighted door-to-door, community level outreach and mobile vaccination clinics as ways to bring the vaccine to more Americans this summer.

In addition, the White House is deploying federal “surge response teams” to help local officials mitigate the spread of the fast-moving delta variant areas of the country with low vaccination rates.

The White House expects 160 million Americans to be fully vaccinated by the end of the week, with Biden on Tuesday declaring that the virus “is on the run” and highlighting the “hard fought progress” against the pandemic. Still, the rate of vaccinations has slowed in recent weeks and officials have acknowledged it will take a concerted effort to reach Americans who have yet to get the shot.

The U.S. narrowly missed Biden’s July 4 goal of having 70 percent of U.S. adults receive at least one dose of a COVID-19 vaccine. As of Monday, 67 percent of had received at least one dose.

The Biden administration predicts that 70 percent of those 27 and older will have received at least one dose after data from the July 4 weekend is collected. Officials project that it will take a few more weeks to reach younger adults.

Biden on Tuesday did not announce any new goals or deadlines for getting the population vaccinated. Instead, the president and his top health officials emphasized that their focus is on getting as many people vaccinated as possible to prevent future outbreaks and block the virus from mutating further, a point of concern as new, more contagious variants spread.

“If you’re vaccinated you’re protected; if you’re unvaccinated, you’re not,” Biden said Tuesday, noting that individuals are putting their friends and family at risk by not getting the vaccine.

“Do it now, for yourself and the people you care about. For your neighborhood, for your country. It sounds corny but it’s the patriotic thing to do,” he added. 

The delta variant now accounts for roughly 25 percent of cases in the U.S., administration officials said last week. The spread of the more transmissible and potentially deadly variant has coincided with outbreaks concentrated in less vaccinated pockets of the country.

Arkansas, Florida, Missouri and Nevada are among the states that have seen a significant uptick in COVID-19 cases in recent weeks, even as national numbers are a tiny fraction of what they were just a few months ago.

About 55 percent of U.S. adults are fully vaccinated. Studies have shown that the vaccines are effective against the delta variant, but health experts are emphasizing that individuals are significantly better protected when they are fully vaccinated.

“We can’t count on our level of vaccination to date as keeping us from having these regional surges,” said Michael Osterholm, a prominent epidemiologist who served on Biden’s coronavirus advisory team during the transition.

White House coronavirus coordinator Jeff Zients made the rounds on the Sunday talk shows over the July 4 weekend, celebrating the progress made on the virus while emphasizing the need to take further steps to make it even easier for those who haven’t gotten vaccinated yet to do so.

“I do believe confidence will continue to grow. But we need to continue to make it even easier to get vaccinated and answer people's questions. And doctors are really important and other health care providers. So, increasingly, we have vaccines in doctor's offices, in clinics,” Zients said on CNN’s “State of the Union.”

Experts say the Biden administration faces an uphill battle persuading those who have shunned the vaccine to get vaccinated. Osterholm said the best approach to overcoming vaccine hesitancy relies on local messengers to continually address the concerns and questions of individuals.

“All public health is local,” he said. “You can’t just have a federal team swoop into an area and expect to see changes in the vaccine levels. It’s going to occur through local efforts where they know the community.”

Biden has received high marks for his administration’s coronavirus response. A Washington Post-ABC poll published over the weekend found that over six in 10 adults approve of Biden’s job handling the coronavirus pandemic.

The same poll found that three in 10 say they have not received a coronavirus vaccine and probably or definitely will not get one.

The White House has said that its powers are limited when it comes to convincing Americans to get vaccinated.

“As the federal government, we don’t have the luxury of feeling frustrated or feeling upset about individuals not getting the vaccine,” White House press secretary Jen Psaki said Tuesday. “It is ultimately up to individuals, and we certainly recognize that as well. But we’re going to continue to press as hard as we can to use the best practices to continue to increase the vaccination rates around the country.”

John Anzalone, the top pollster for Biden's 2020 presidential campaign, said the lagging vaccination rates would not negatively impact Biden's overall favorability on his handling of the pandemic.

“At this point, people understand that there are people who won’t get it," Anzalone said. He noted that people may be mad at others' personal decisions but will not take it out on Biden, who has been rewarded for his response to the virus.

“The administration has not let up in any way on their efforts. In some ways they have doubled down on the efforts because now comes the really hard work of going door to door and going deep into both urban and rural communities,” Anzalone added. “They are still doing their part along with states but the vaccine resistant are always going to be the vaccine resistant.”