The Ministry of Health in Saudi Arabia told world health officials that two health care workers became ill this month after being exposed to patients with the virus. One is critically ill.
Since September 2012, the World Health Organization has been informed of 40 confirmed cases of the virus, and 20 of the patients have died. The deaths occurred in Britain, Germany, Saudi Arabia, and Jordan.
Experts have suggested calling the new virus MERS, for Middle East Respiratory Syndrome, but officials have not signed off on that yet.
Experts are watching carefully for signs that the deadly virus can spread from person-to-person. Health officials say the virus has likely already spread between people in some circumstances, including hospital patients in France.
The new virus has caused severe respiratory disease in patients, some of them needing mechanical ventilators to help them breathe.
One of the Saudi health care workers is a 45-year-old man who is in critical condition. The other is a 43-year-old woman in stable condition. No other details about their jobs or where they work were released. Health workers were previously infected in a cluster in Jordan, though that was before the new coronavirus had been identified and before any special measures were taken to prevent its spread. That is not the case in Saudi Arabia and officials worry any new spread to health workers could suggest the virus is becoming more transmissible to people.
The new virus has been compared to SARS, an unusual pneumonia that first surfaced in China in late 2002 and erupted into a deadly international outbreak in early 2003. Spread of the virus in hospitals was a key development in the epidemic.
Ultimately, more than 8,000 cases were reported in about 30 countries, including eight people in the United States. The global tally included 774 deaths.
The SARS outbreak was declared contained by the summer of 2003, thanks to such measures as quarantines, hospital isolation of suspected cases, travel restrictions and the screening of airline passengers.
The WHO is currently not recommending any travel restrictions or special screening at airports or border crossings. Officials worry it will flare into an outbreak as big or worse. The new virus and SARS are both coronaviruses, a germ family that includes some cold viruses.
The new virus is distinct from SARS, but health officials worry it has potential to flare into a SARS-like international outbreak. But many questions remain about how it is spread, where it originated, and how deadly it truly is.