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Johnson & Johnson vaccine: What to know about efficacy

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NBC News medical contributors Dr. Vin Gupta and Dr. Natalie Azar join the 3rd hour of TODAY to discuss the Johnson & Johnson’s one-shot COVID-19 vaccine. Azar notes that its overall efficacy was 66% for prevention of moderate to severe disease and in the U.S. that increased to 72%. ****Dr. Natalie Azar's comments have been edited to clarify what she said about the number of vaccines that Johnson & Johnson has pledged to make available.**