Dr. Wafaa El-Sadr, a professor of medicine and epidemiology at Columbia University, says there’s “absolutely no need to panic” amid the Legionnaires' Disease outbreak on the Upper East Side. El-Sadr said "it is only people who are particularly susceptible" to the disease - which the Health Department says includes adults age 50 and older, people who smoke or vape, people with chronic lung disease, people with weakened immune systems or people taking medications that suppress the immune system -