As Johnson & Johnson's COVID-19 vaccine remains in limbo, Moderna and Pfizer are ramping up efforts to have shots available for all adults by summer.
Another Centers for Disease Control and Prevention meeting on the Johnson & Johnson pause is set for April 23.
And while the other two companies behind the active COVID-19 vaccines are setting lofty goals, virus cases are on the rise.
New cases are climbing in 22 states, averaging more than 70,000 cases per day.
The CDC says of the more than 78 million Americans fully vaccinated, there have been 5,800 reported cases of breakthrough infections, 396 hospitalizations and 74 deaths. But health experts are stressing those numbers show those cases are very rare.
Not as rare at this point in the U.S. are variants, which are part of the reason behind a dangerous surge in Michigan.
"Which is just like a runaway train right now. Our emergency centers and our COVID centers are filing up once again," says Beaumont Hospital Chief Medical Officer Dr. Nicholas Gilpin.
The U.S. is making plans just in case the vaccines need a booster. But as the shots do offer extremely effective protection already, the plea to vaccinate continues.
"We're going to see many waves in many places, and we need to get those vaccines in arms," says Michigan ER physician Dr. Rob Davidson.