Johnson & Johnson's single-shot Covid-19 vaccine has an overall efficacy of 66 percent, the company announced Friday, following results from a phase 3 trial of almost 44,000 people across many countries. The figure however was higher in the United States and lower in South Africa, where a more transmissible variant is dominant. "We're proud to have reached this critical milestone and our commitment to address this global health crisis continues with urgency for everyone, everywhere," the company's CEO Alex Gorsky said. ia/ft