MONDAY, Jan. 27, 2014 (HealthDay News) -- Although Middle East respiratory syndrome (MERS) hasn't become a worldwide threat, experts say people aren't out of the woods yet.
As of January, 178 people in 10 countries have been diagnosed with MERS and 75 have died from the viral illness, according to the U.S. Centers for Disease Control and Prevention. So far, no cases of MERS have been reported in the United States.
A new study from Saudi Arabia suggests that people with chronic medical conditions might be more vulnerable to the virus. The study also found that the virus doesn't spread easily to others, such as health care workers.
MERS is a coronavirus, a common type of infection that attacks the respiratory system. Most of these viruses cause only minor symptoms, such as runny nose, cough, sore throat and fever, according to the CDC. But the viruses can sometimes cause lower respiratory tract illnesses, such as pneumonia.
MERS often is compared with its cousin, severe acute respiratory syndrome (SARS), another coronavirus that spread across the globe in 2003. During the outbreak, there were nearly 8,100 cases and 744 deaths, according to the CDC.
With effective public health measures, SARS was contained and there hasn't been a case reported since 2004, the agency said.
However, based on her experience with the SARS outbreak, Dr. Connie Price, chief of infectious diseases at Denver Health and Hospital, doesn't want to see the threat of MERS downplayed just yet.
"I want to make sure we don't get too comfortable that MERS is easy to control," said Price, an associate professor of medicine at the University of Colorado, Denver. "We need to stay alert and keep on our toes to make sure we are respecting the potential threat."
"There is potential that this could continue to evolve and adapt and become able to spread more easily, and that's what we want to nip in the bud," said Price, co-author of an editorial that accompanied the study in the Jan. 28 online edition of the journal Annals of Internal Medicine.
It is possible that public health measures have prevented that potential from occurring, Price said. "If we do nothing, I think it probably would continue to spread," she said. "We have kept it confined to four or five countries in the Middle East. We should feel comfortable, but comfortable doesn't mean non-vigilant."
Confirmed cases of MERS have been reported in France, Italy, the United Kingdom, Jordan, Kuwait, Oman, Qatar, Saudi Arabia, Tunisia and United Arab Emirates, according to the CDC.
"Infection-control measures have made it such that SARS is just not able to survive among humans, so it went away," Price said. "Hopefully, the same will happen with MERS."
These measures include early detection and isolation of infected patients, according to the CDC. For health care workers, infection-control measures include washing hands frequently and wearing protective masks, goggles, gloves and gowns when treating patients.
In the new study, Saudi Arabian researchers looked at 12 patients hospitalized with MERS to see if they could find a common thread that made them susceptible to the disease.
"These patients were extremely ill because of respiratory failure and multiple organ failure," said lead researcher Dr. Yaseen Arabi, medical director of respiratory services at King Saud bin Abdulaziz University for Health Sciences, in Riyadh.
"The striking thing was these patients all had [other coexisting conditions]," Arabi said. "It looks like this virus affects predominately people with chronic illnesses. It looks like the virus doesn't transmit easily and transmits mainly to patients who have underlying chronic diseases."
Arabi's team studied MERS patients in three hospitals in Saudi Arabia. All of those who were critically ill had other medical conditions, such as heart disease, asthma, diabetes or kidney failure. Seven patients died.
This finding strongly suggests that patients with other serious medical problems are the ones most susceptible to MERS, Arabi said.
Three nurses got sick while caring for patients with MERS, but they were not wearing protective gear. Only one of these nurses became severely ill and was included among the study patients. The other nurses didn't have symptoms, Arabi said. "The risk to health care workers is small, but it is real," he said.
Although MERS has been contained thus far, Arabi said he is also concerned that it could spread and start a pandemic.
"The concern originates from the fact that MERS is from the same family as the SARS virus, and SARS was notorious for spreading very quickly," he said.
Since MERS was identified in September 2012, the number of cases has been low, Arabi said. "Thus far, at least, MERS doesn't look like a real pandemic threat," he said.
If, however, the virus were to mutate, making it easier to pass from person to person, it might become a worldwide threat, Arabi said. "That's the real concern, but it hasn't mutated thus far," he said.
To learn more about MERS, visit the U.S. Centers for Disease Control and Prevention.