MERS Cases Highlight Risk to Healthcare Workers

May 13, 2014

Update: The Florida Department of Health said Wednesday that 2 patients who became ill after exposure to a MERS patient conclusively tested negative for MERS-CoV. Testing of 18 other healthcare workers who were exposed to the patient wasn't complete, but preliminary results have come back negative.

The second confirmed case of Middle East Respiratory Syndrome (MERS) in the United States, like the first one, points to a hard-hit patient population — healthcare workers. They comprise 1 in 5 cases worldwide, according to the Centers for Disease Control and Prevention (CDC).

In the first case in Indiana, announced May 2, and the one in Florida announced today, the patients were healthcare workers who has travelled from Saudi Arabia — the hotbed of the MERS outbreak — to visit family in this country.

At a news conference today, CDC Director Thomas Frieden, MD, MPH, said that transmission of the MERS coronavirus (CoV) requires close contact, the sort that occurs when someone cares for an infected person at home or in the hospital. Otherwise, "we don't think there's a risk [of easy transmission] from casual contact," said Dr. Frieden.

As of May 12, the number of confirmed MERS cases reported to the World Health Organization (WHO) stood at 538, with 138 deaths, since the coronavirus was first detected in 2012. A recent WHO news release stated that most human-to-human transmissions have occurred in healthcare facilities, and that healthcare workers account for one fourth of the cases, a proportion that differs somewhat from the CDC figure.

Both the WHO and the CDC say that the pattern of MERS infections demands that hospitals and clinicians implement standard protocols to prevent and control infections, such as donning masks, gowns, and gloves; isolating patients with a suspected case; and furloughing healthcare workers who have been exposed to such patients.

"This is not a virus we can treat right now with specific antivirals, so we think that excellent infection control is absolutely critical," said Anne Schuchat, MD, director of the CDC's National Center for Immunization and Respiratory Diseases, at today's news conference.

Ill From the Beginning of the Trip

The second patient who tested positive for MERS-CoV flew from Jeddah in Saudi Arabia on May 1 to Orlando, Florida, on 4 different connecting flights — Jeddah to London, England; London to Boston, Massachusetts; Boston to Atlanta, Georgia; and Atlanta to Orlando.

The person, who works in a Saudi healthcare facility, began feeling ill on the Jeddah-London leg of the trip, "and continued to feel unwell on subsequent flights, with reported symptoms including fever, chills, and a slight cough," said Dr. Schuchat. On May 9, the person went to the emergency department of Dr. P. Phillips Hospital in Orlando and was admitted.

Antonio Crespo, MD, the hospital's chief quality officer and an infectious disease specialist, said that the patient is in "good condition and improving."

"We are taking every precaution, but believe the risk of transmission from this patient is low since his symptoms were mild and he was not coughing when he arrived at the hospital," Dr. Crespo said in a news release issued today by the Florida Department of Health (FDOH).

FDOH Secretary and State Surgeon General John Armstrong, MD, said at today's news conference that he was pleased with the Orlando hospital's response to the MERS threat. The CDC's Dr. Frieden added that the hospital isolated the patient promptly.

Virus Doesn't Appear to Have Mutated to Dangerous Form

Public health authorities also are worried about potential exposure to MERS-CoV among the Florida patient's fellow airline passengers, whom they are trying to contact. This means notifying more than 500 individuals who flew with the patient on the legs of the journey between London and Orlando, said Dr. Schuchat. These 500-plus individuals eventually dispersed to some 20 states, so the CDC is asking their state health departments to help in the hunt.

The number of people to contact will increase once the number of passengers on the flight from Jeddah to London is determined.

Dr. Schuchat noted that the incubation period for MERS-CoV is often 5 days with an outlier limit of 14. If the airline passengers on the patient's various flights have not developed symptoms by now, it's unlikely they will in the future, she said. "We're getting toward the end of the period when it would be biologically possible for them to acquire an infection."

"We don't actually know that there is a risk associated with airline travel," added Dr. Frieden. In other outbreaks of infectious disease, he said, the CDC has focused only on flights longer than 8 hours or who sat in the two rows in front or behind an infected person. "Out of an abundance of caution, we are, as we did in the Indiana case, reaching out to all of the people who can be identified."

The number of MERS cases in Saudi Arabia has spiked since March 2014, prompting concern that the virus may have mutated to a more easily transmitted form. That does not appear to be the case, however, said Dr. Frieden. Genomic sequencing of the virus that infected the patient in Indiana did not reveal any significant change over time. Instead, the MERS surge in Saudi Arabia seems to stem in part from better monitoring for the virus, which is picking up the disease in its initial stages.

"That's a good thing," said Dr. Frieden. "That means we're able to find patients earlier, protect them and others from [virus] spread, and get a better handle on how to stop the disease transmission,"

More information on MERS is available on the CDC Web site.

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