In this May 13, 2014 photo, Muslim pilgrims wear surgical masks to prevent infection from respiratory virus known as the Middle East respiratory syndrome (MERS) in the holy city of Mecca, Saudi Arabia. (AP)

Five more deaths from the MERS coronavirus were announced on Saturday by the Health Ministry bringing the death toll to 168 since September 2012.

The ministry said nine more confirmed cases of MERS have been reported in last 24 hours, bringing the total number of infected cases to 629 since the outbreak of the chronic disease.

The latest fatalities are three patients from a government hospital in Jeddah, one from Riyadh and one from Madinah.

The three victims in Jeddah are a woman, aged 80, and two men, aged 55 and 67.

The two other casualties are a 71-year-old man in Riyadh and a 77-year-old man in Madinah.
The ministry said that one patient recovered and has been discharged.

Meanwhile, scientists leading the fight against the deadly virus 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. 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 US 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 said. “We assume they are less infectious (to others), but we don’t know.”