Johnson & Johnson Announces 1-Shot Vaccine is 66% Effective Against Moderate to Severe COVID-19

Johnson & Johnson, the only major drug maker developing a single-dose vaccine for Covid, announced on Friday that its shot provided strong protection against Covid-19, potentially offering another powerful tool in a desperate race against a worldwide rise in virus mutations.

But the results came with a significant cautionary note: The vaccine’s efficacy rate dropped from 72 percent in the United States to 57 percent in South Africa, where a highly contagious variant is driving most cases.

A global study of nearly 44,000 found that the COVID-19 vaccine made by Johnson & Johnson is 66% effective in preventing moderate to severe disease.

The study was conducted in the U.S., Latin America and South Africa. The vaccine did better at preventing disease in the U.S. – 72% — and less well in South Africa – 57% efficacy. The efficacy seen in Latin America was 66%.

The South African results are troubling because of the coronavirus variant spreading there that has now been detected in the U.S., raising concerns...