The U.S. Food and Drug Administration (FDA) authorized Johnson & Johnson's COVID-19 vaccine for emergency use on Saturday (Feb. 27), making it the third shot cleared for use in the country.
"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," Acting FDA Commissioner Dr. Janet Woodcock said in a statement.
An FDA analysis showed that the single-shot vaccine had a 72% overall efficacy rate in the U.S. and 64% in South Africa, where a highly-transmissible coronavirus variant is causing most new cases, The New York Times reported. The efficacy rate in South Africa is slightly higher than the company had estimated in a recent report, up by seven percentage points.
In terms of protecting against severe disease, the vaccine showed 86% efficacy in the U.S. and 82% in South Africa, the Times reported.
And the shot was "100 percent effective in preventing hospitalization and deaths, and that's really what's important," Dr. Nancy M. Bennett, a professor of medicine and public health sciences at the University of Rochester School of Medicine and Dentistry, told The Washington Post. "Those facts are the most important thing to recognize."
Johnson & Johnson also monitored for asymptomatic infections by checking for coronavirus antibodies in a small number of volunteers 71 days after they got either the vaccine or a placebo shot. The data shows that the vaccine has 74% efficacy against asymptomatic infections, but "there is uncertainty about the interpretation of these data," given the small number of volunteers assessed, the FDA noted, according to the Times.
Despite having a lower overall efficacy rate than the Pfizer-BioNTech and Moderna vaccines, which are each more than 90% effective, the single-shot vaccine could still make a big difference because it can be stored for months at refrigerator temperatures, rather than requiring deep-freezing, The Washington Post reported.
Additionally, the vaccine shows more than 80% efficacy against severe disease and 100% efficacy against hospitalization; this level of protection can prevent trips to the intensive care unit (ICU), thus lessening the burden on health care systems, as well as help vaccinated people avoid the potential long-term impacts of severe COVID-19 infection.
"Don't get caught up, necessarily, on the number game, because it's a really good vaccine, and what we need is as many good vaccines as possible," Dr. Anthony S. Fauci,the Biden administration's chief medical adviser on COVID-19, told the Times on Saturday (Feb. 27). "Rather than parsing the difference between 94 and 72, accept the fact that now you have three highly effective vaccines. Period."
Similar to the vaccine developed by the University of Oxford and AstraZeneca, the Johnson & Johnson shot contains a weakened version of a common cold virus, known as an adenovirus, Live Science previously reported. Scientists genetically altered the adenovirus, named ad26, so it can no longer infect human cells and then added genes that code for the coronavirus spike protein, a structure that sticks off the pathogen's surface and helps the virus bind to cells.
Once inside the body, the vaccine trains the immune system to recognize the spike protein and target the coronavirus for destruction. Janssen Pharmaceuticals, the Johnson & Johnson company that developed the COVID-19 vaccine, used a similar strategy to develop its existing Ebola vaccine.
With FDA approval in hand, Johnson & Johnson can now ship about 4 million vaccine doses across the U.S., Dr. Richard Nettles, the vice president of U.S. medical affairs at Janssen Pharmaceuticals, told lawmakers earlier this month, the Times reported. Another 16 million doses should be ready by the end of March and 100 million by the end of June, although the company is currently far behind the number of doses pledged in its federal contract, according to the Times.
Originally published on Live Science.