The study enrolled 30,420 adult participants at 99 locations across the United States, including over 600 participants at Brigham. Results of the primary analysis of the ongoing phase 3 clinical trial of the US biotechnology company Moderna’s Coronavirus (( COVID-19 ) The vaccine has shown a 94.1% effectiveness of the therapeutic in preventing symptomatic infections and serious illnesses, according to a peer-reviewed study. The study, published Wednesday in the New England Journal of Medicine, found that among over 30,000 participants randomly assigned to receive the vaccine or placebo, 11 in the vaccine group developed symptomatic COVID-19, compared with 185 participants who received the placebo. The researchers said this showed 94.1% effectiveness in preventing symptomatic COVID-19, adding that cases of serious illness only occurred in participants who received the placebo. “Our work continues. In the next few months we will have more and more data to better define how this va