...New research offers encouraging evidence about how the Johnson & Johnson vaccine stacks up against its competitors — and the delta variant... Earlier clinical trials showed the Johnson & Johnson vaccine was 66 percent effective overall in preventing moderate to severe disease four weeks after the shot, with effectiveness varying depending on location. Its competitors from Pfizer and Moderna, on the other hand, recorded 90 percent-plus effectiveness against the coronavirus.... ...A trial out of South Africa has caught the attention of people, particularly infectious-disease experts, with regard to the effectiveness of Johnson & Johnson’s vaccine against the delta variant. The...