Scientists leading the fight against Middle East Respiratory Syndrome say the next critical front will be understanding how the virus behaves in people with milder infections, who may be spreading the illness without being aware they have it.
Establishing that may be critical to stopping the spread of MERS, which emerged in the Middle East in 2012 and has so far infected more than 500 patients in Saudi Arabia alone. It kills about 30 percent of those who are infected.
It is becoming increasingly clear that people can be infected with MERS without developing severe respiratory disease, said Dr David Swerdlow, who heads the MERS response team at the U.S. Centers for Disease Control and Prevention.
"You don't have to be in the intensive care unit with pneumonia to have a case of MERS," Swerdlow told Reuters. "We assume they are less infectious (to others), but we don't know."