There's good news for the millions of Americans who've already received a dose or two of Moderna's COVID-19 vaccine: New research shows the vaccine should protect against illness for at least six months. The new study tracked 33 participants in the trials that led to the vaccine's approval. Six months after having received their second vaccine dose, "antibody activity remained high in all age groups," according to a team led by Nicole Doria-Rose of the U.S. National Institute of Allergy and Infectious Diseases (NIAID). Her group published their findings April 6 in the New England Journal of Medicine.