Johnson & Johnson’s COVID-19 vaccine was approved for emergency usage in the United States by the Food and Drug Administration on Feb. 27.

The vaccine is  now the third to be approved for use nationwide and it is the first single-shot vaccine, whereas the Moderna and Pfizer vaccines consist of two doses.

“The authorization of this vaccine expands the availability of vaccines, the best medical prevention method for COVID-19, to help us in the fight against this pandemic, which has claimed over half a million lives in the United States,” Dr. Janet Woodcock, acting FDA commissioner, said.

“The FDA, through our open and transparent scientific review process, has now authorized three COVID-19 vaccines with the urgency called for during this pandemic, using the agency’s rigorous standards for safety, effectiveness and manufacturing quality needed to support emergency use authorization.”

FDA scientists have found the Johnson & Johnson vaccine was 72%effective at preventing “severe illness in clinical trials” in the United States, according to NBC News.

In regions where the COVID-19 strains are circulating, such as Latin America, the vaccine was found to be 66%effective in combating the disease. Studies from South Africa reported it was 64%effective, according to NBC News.

Johnson & Johnson is prepared to adjust the vaccine for new variants and the company is also working to develop software that will aid the fight against new variants, according to CNBC.

“We’re quite confident based upon the clinical data that we already have with our vaccine that we’re going to see a very robust response, but we’re simultaneously doing the exact same thing [as other companies working on variants],” Alex Gorsky, CEO of Johnson & Johnson, said.

Many have been anticipating the approval of the Johnson & Johnson  COVID-19 vaccine in the United States because it requires only a single shot for full protection against the virus.

On March 10, the Biden administration announced that they are directing the Department of Health and Human Services to purchase 100 million more doses of the Johnson & Johnson vaccine, according to CNN.

Experts believe that this single-shot vaccine is a key part on the road to recovery from the deadly disease.

“All three of them are really quite good, and people should take the one that’s most available to them,” Dr. Anthony Fauci, the White House chief medical adviser, said. “If you go to a place and you have J&J, and that’s the one that’s available now, I would take it.”