In the three months since Johnson & Johnson’s COVID-19 vaccine received emergency use authorization from the U.S. Food and Drug Administration, more than 10 million Americans have received the vaccine, according to the Centers for Disease Control and Prevention. The single-shot viral vector vaccine — developed in collaboration with Beth Israel Deaconess Medical Center (BIDMC) immunologist Dan Barouch — was authorized for use based on clinical trial data showing strong clinical efficacy against symptomatic COVID-19 in the United States, Latin America and South Africa. In a new study published in Nature, Barouch, director of BIDMC’s Center for Virology and Vaccine Research, and colleagues report on the antibody and cellular immune responses generated by the Ad26.COV2.S vaccine against the original viral strain and against SARS-CoV-2 variants of concern. The team found that this vaccine induced immune responses against all the viral variants.