WASHINGTON (NEXSTAR) – A third COVID-19 vaccine moved into its final step Friday before it can go into the arms of Americans.

A clinical trial found the Johnson & Johnson vaccine can protect against the virus with just one shot, but it’s not as strong as the two-dose vaccines.

“The overall efficacy for severe disease was 85 percent,” said Dr. Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases.

That’s the percentage Fauci is focused on, instead of the overall efficacy of the shot in the U.S., 72 percent compared to about 95 percent in the Pfizer and Moderna vaccines.

Fauci said the effectiveness of the Johnson & Johnson shot, combined with its simpler transportation and storage requirements, gives him hope.

“This has important potential and real implications both domestically and globally,” he said.

The CDC confirmed Friday that cases of all three variants of COVID-19 from the U.K., South Africa and Brazil are now in the U.S.

“This is a wake-up call to all of us,” Fauci said.

As the country continues to see different mutations, Fauci warned the vaccines will have to adapt to the variants.

“Make versions of the vaccine that are specifically directed toward whatever mutation is prevalent at any given time,” he said. “Viruses cannot mutate if they cannot replicate.”

That’s why Fauci said it’s vital to vaccinate Americans as quickly as possible.

“No matter what happens with other approvals, we will have sufficient supply to vaccinate the country,” said Andy Slavitt, the senior advisor to the White House COVID Response Team.

Slavitt reported the U.S. has administered 26 million doses so far and exceeded more than a million vaccinations per day.

Until the FDA approves the Johnson & Johnson shot, the Biden administration will stay focused on distributing the Pfizer and Moderna supply.

“Enough doses to give two shots to Americans by the end of the summer,” said White House Press Secretary Jen Psaki.