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

The White House said 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, but the distribution would be backloaded.

Though the new shot is easier to administer and requires only one dose, the administration is not altering its distribution plans.

The White House is encouraging Americans to take the first dose available to them, regardless of manufacturer.