Johnson & Johnson said Friday, Jan. 29, that its single-dose coronavirus vaccine provided strong protection against moderate to severe COVID-19, although it appears to have a lower effectiveness against a new coronavirus variant first identified in South Africa. Preliminary results released by the company show that the vaccine had an overall effectiveness of 66 percent against moderate to severe disease 28 days after vaccination. Effectiveness is a measure of how well a vaccine works within the controlled environment of a clinical trial. Real-world effectiveness may be lower. Effectiveness was similar for all age groups, including those 60 years and older. To read the full story.