1/ Johnson and Johnson’s single-dose Covid-19 vaccine was 66% effective overall at preventing moderate to severe illness in a global study. In the U.S., the vaccine was 72% effective, but the efficacy rate dropped to 57% in South Africa, where a highly contagious variant is driving new cases. The vaccine was particularly effective at stopping severe disease in all regions, preventing 85% of severe infections and 100% of hospitalizations and deaths. Johnson and Johnson said it planned to apply for emergency authorization of its vaccine from the FDA, putting it on track to receive clearance later in February. (Washington Post / Bloomberg / Politico / New York Times / The Guardian / NBC News)