Largest U.S. Nurses Union Slams CDC's Relaxed Mask Guidance as 'Dangerous' On 5/19/21 at 3:45 PM EDT The largest union of registered nurses in the U.S. called upon the Centers for Disease Control and Prevention (CDC) to revise its relaxed mask guidelines for individuals who have been fully vaccinated against COVID-19, just two days after California broke with the federal agency and extended its own mask mandate. National Nurses United President Jean Ross decried the CDC's updated guidance as "dangerous" and "disappointingly not in the best interest of public health" during a Wednesday news conference. "We understand everyone's desire to get back to normal. Trust us—we nurses would like nothing better," Ross said. "But we are a profession based upon science, and the science shows this is exactly the wrong time to be relaxing our multi-pronged approach to infection control, that studies show actually work to control the virus."