The Food and Drug Administration appears to be closing in on an emergency use authorization for the single-dose Johnson & Johnson COVID-19 vaccine, which a large clinical trial has shown to be safe and effective. And the "most encouraging" aspect in the FDA's analysis may be the data that suggest the shot works in areas where highly contagious variants are spreading, like Brazil and South Africa.
The overall efficacy rate — that is, protection against any symptomatic infection — in the South African trial was lower than it was in the United States initially, but the numbers did start to even out over time, and after a month, the shot's efficacy rate against severe infections was 82 percent. The figures out of Brazil show a similar trajectory, though the efficacy rate against severe infections was actually slightly higher than in the U.S.
Of course, the trial data is not a guarantee of the vaccine's effectiveness in a real-world setting, but the FDA's breakdown should still help alleviate growing concerns that the so-called South African variant, especially, can completely resist vaccinations, an outcome that would add to the challenge of slowing the pandemic going forward.