WASHINGTON — Nearly 4 million doses of the newest COVID-19 vaccine will be shipped Sunday night, and will begin to be delivered to states for injections starting on Tuesday.

White House COVID-19 coordinator Jeff Zients announced that the entire stockpile of the newly approved single-dose Johnson & Johnson vaccine will go out immediately. J&J will deliver about 16 million more doses by the end of March and 100 million total by the end of June.

Though the new shot is easier to administer and requires only one dose, the administration is not altering its distribution plans. Zients says, “We’re distributing the J&J vaccine as we do the Moderna vaccine and the Pfizer vaccine.”

Dr. Anthony Fauci, the nation’s top infectious disease expert, and Dr. Marcella Nunez-Smith, the chair of the White House equity task force, encouraged Americans to take the first dose available to them, regardless of manufacturer.

Advisers to the Centers for Disease Control and Prevention voted overwhelmingly to recommend the vaccine for adults 18 years old and up. The ruling followed emergency clearance of the vaccine by U.S. regulators a day earlier.

Members of the group emphasized that all three vaccines now available in the U.S. are highly protective against the worst effects of the virus, including hospitalization and death.

In Grand Rapids, Mercy Health St. Mary’s Chief Medical Officer Dr. Matt Biersack said the new vaccine brings new possibilities for tackling the coronavirus pandemic.

“We think we’re going to be able to use it in new and different ways than we’ve been using Pfizer and Moderna,” Biersack said.

He said the approval of the single-dose shot will be easier to administer.

“This option brings with it a lot more flexibility because it doesn’t have the ultra-cold storage requirements that the other two vaccines did,” Biersack said. “This will allow us to get further out into rural communities.”

Health officials are eager to have an easier-to-use vaccine against COVID-19, which has killed more than 511,000 Americans and continues to mutate in troubling ways.

CDC recommendations are not binding on state governments or doctors, but are widely heeded by the medical community. The same CDC panel previously recommended use of the two vaccines from Pfizer and Moderna authorized in December.

— News 8’s Jacqueline Francis contributed to this report.