More evidence of COVID-19 vaccine effectiveness. A study in the January 7 Morbidity and Mortality Weekly Report provides further evidence of the effectiveness of COVID-19 vaccines in preventing severe illness and death and helps to clarify who is at risk despite vaccination. In an analysis of over 1.2 million people who had received two doses of the Moderna, Pfizer-BioNTech, or Johnson and Johnson vaccines, 2,246 developed COVID-19 (18 per 10,000), 189 had a severe outcome (1.5 per 10,000) and 36 died (0.3 per 10,000). Severe outcomes were more common in people 65 years of age or older or immunosuppressed or with additional risk factors, including pulmonary disease, liver disease, chronic kidney disease, neurologic disease, diabetes, and cardiac disease. Every person who had a severe outcome had at least one risk factor, and 78% of those who died had at least four. The authors note the importance of people with identifiable risk factors receiving additional vaccine doses and, regardless of vaccine status, taking precautions to avoid exposure.