President Joe Biden on Tuesday set a new vaccination goal to deliver at least one shot to 70 percent of adult Americans by July 4 as he tackles the vexing problem of winning over the “doubters” and those unmotivated to get inoculated.

Demand for vaccines has dropped off markedly nationwide, with some states leaving more than half their available doses unordered. Aiming to make it easier to get shots, Biden called for states to make vaccines available on a walk-in basis and he will direct many pharmacies to do likewise.

His administration for the first time also is moving to shift doses from states with weaker demand to areas with stronger interest in the shots.

“You do need to get vaccinated,” Biden said from the White House. “Even if your chance of getting seriously ill is low, why take the risk? It could save your life or the lives of somebody you love.”

Biden’s goal equates to delivering at least the first shot to 181 million adults and fully vaccinating 160 million. It’s a tacit acknowledgment of the declining interest in shots.

Already more than 56 percent of American adults have received at least one dose of a Covid-19 vaccine and nearly 105 million are fully vaccinated. The U.S. is currently administering first doses at a rate of about 965,000 per day — half the rate of three weeks ago, but almost twice as fast as needed to meet Biden’s target.

“I’d like to get it 100 percent, but I think realistically we can get to that place between now and July Fourth,” Biden said of his new goal.

He said the administration would focus on three areas as it tries to ramp up the pace of vaccinations:

—Adults who need more convincing to take the vaccine.

—Those who have struggled or are in no hurry to obtain a shot.

—Adolescents aged 12-15, once federal authorities approve vaccination for that age group.

Acknowledging that “the pace of vaccination is slowing,” Biden predicted the inoculation effort is “going to be harder” when it comes to convincing “doubters” of the need to get their shots.

He said the most effective argument to those people would be to protect those they love. “This is your choice: It’s life and death.”

Biden’s push comes as his administration has shifted away from setting a target for the U.S. to reach “herd immunity,” instead focusing on delivering as many shots into arms as possible. Officials said Biden’s vaccination target would result in a significant reduction in Covid-19 cases heading into the summer.

To that end, the Biden administration is shifting the government’s focus toward expanding smaller and mobile vaccination clinics to deliver doses to harder-to-reach communities. It is also spending hundreds of millions of dollars to try to boost interest in vaccines through education campaigns and greater access to shots through community organizations that can help bring people to clinics.