"There's no doubt that the people who receive the J&J vaccine are less protected against disease," than those who get two doses of the other shots, said Stanford professor Dr. Michael Lin. "From the principle of taking easy steps to prevent really bad outcomes, this is really a no brainer."... The U.S. National Institute of Allergy and Infectious Diseases (NIAID) is running a trial to determine the need for boosting all currently authorized shots with another dose of Moderna's vaccine. NIAID scientist Dr. John Beigel told Reuters the agency hopes to have that data by September to help inform regulators' decisions on boosters. As long as case counts remain low in the United States, J&J recipients should wait for more data, he said. If Delta variant-driven infections and hospitalizations increase significantly, he said, "then decisions might need to be made with an absence of data. But right now, I do think it's appropriate that they wait."