Johnson & Johnson said Friday that its single-dose COVID-19 vaccine reduced rates of moderate and severe disease, but the shot appeared less effective in South Africa, where a new coronavirus variant has become common.
Overall, the vaccine was 66% effective at preventing moderate to severe disease 28 days after vaccination. But efficacy differed depending on geography. The shot was 72% effective among clinical trial volunteers in the U.S, but 66% among those in Latin America, and just 57% among those in South Africa. Though markedly below the levels seen with the first two authorized COVID-19 vaccines, those rates are above the thresholds originally set by the U.S. Food and Drug Administration for a vaccine to be considered useful.
The vaccine reduced severe disease alone by 85%, and prevented COVID-related hospitalization or death, Johnson & Johnson said.
“In a pandemic, if you can, with a single-dose vaccine, very quickly eliminate the severe consequences of death, hospitalization, and severe disease, that’s what’s important for society,” Paul Stoffels, the company’s chief scientific officer, told STAT.
Eric Topol, director and founder of the Scripps Research Translational Institute, called the results “disappointing,” but added that a vaccine that prevents the most serious outcomes, such as hospitalization and death, is still valuable. “It reinforces how lucky we were that the first two were more effective,” he added.
Dr. Anthony Fauci, the director of the National Institute for Allergy and Infectious Diseases, cautioned at a press conference against making too much of comparisons to prior vaccines, calling the result “extraordinarily important,” noting that severe disease was reduced across the board, even in regions where new variants of the virus were common.
“So this has really important domestic and global public health implications,” Fauci said, “things that we know about this particular candidate that even add to the importance globally, namely the minimal cold chain requirements, the inexpensive nature of it, the fact that it is one shot and that the company can actually produce in a reasonable period of time, billions of doses.”