President Trump said his national security advisor does not need to apologize after a reporter said Michael Waltz mistakenly invited him into an encrypted group chat about military operations. Democrats accused the Trump officials of a security breach. NBC News' Peter Alexander reports. Doctors say concerned parents can get their children the measles vaccine as early as six months rather than at the one-year mark which has been the standard recommendation. As the measles outbreak in Texas reaches nearly 330 cases, NBC News' Emilie Ikeda reports on what parents should know to keep their youngest children safe. Frank Bisignano, President Trump's pick to lead the Social Security Administration, faced senators in a high-stakes hearing on Tuesday as concerns over potential changes to entitlement programs mount. NBC News' Ryan Nobles reports. A Maui anesthesiologist was arrested in Hawaii after police say he tried to kill his wife on a popular hiking trail. NBC News' Marissa Parra has the latest on the investigation.