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This award-winning blog supplements the articles in Hospital Infection Control & Prevention.

Mutated MERS Explodes in Korea? Much More Likely Nation’s Health System was Unprepared

The rapid explosion of Middle East Respiratory Syndrome (MERS) in South Korea has raised questions about whether the emerging coronavirus has become more transmissible, as the World Health Organization has dispatched a team to Korea to rapidly discern “the characteristics of the virus and clinical features.”

That said, the outbreak thus far fits the traditional pattern of spread within health care facilities and no sustained transmission in the community. Thus there is some disconnect -- though it may raise general MERS awareness -- in members of the Korean public going about in surgical face masks. “Based on current data and WHO’s risk assessment, there is no evidence to suggest sustained human-to-human transmission in communities and no evidence of airborne transmission,” the World Health Organization reports. “However, MERS is a relatively new disease and information gaps are considerable. The joint mission will bring us a step closer to gaining a better understanding of the nature of this virus.”

As of Monday June 8, the MERS case count in South Korea was 87 patients, including six deaths.That translates to a miniscule mortality rate compared to some of the 50%-60% death rates in hospital outbreaks after MERS emerged in Saudi Arabia in 2012. Saudi officials investigating those outbreaks said they were probably missing a spectrum of milder cases, and that may be the difference in what is happening in Korea.

At any rate, it seems a lack of preparedness and rigorous infection control measures are the most likely explanation for the Korean outbreak, as the apparently undiagnosed index case went to several different health care facilities and exposed patients and health care workers. The 68-year-old male returned from a trip to Bahrain May 4 and became symptomatic about a week later. This fits the MERS incubation period – a mean of 5 days to symptom onset with a range of 2 to 14 days. Now suffering fever and cough, the man went to three different hospitals from May 8th-20th, but MERS testing was not done until May 19th. The sputum sample tested positive for MERS on May 20, after which the patient “was transferred to the nationally designated treatment facility for isolation,” Korean public health officials reported.

Meanwhile, transmission began occurring between and among other patients, visitors and health care workers, setting off a cascade of visits and admissions to at least a dozen other health care facilities. The rapidity of ensuing transmission strongly suggests that the Korean health care system was not prepared for MERs to the degree recommended by the CDC, which has stressed getting an immediate travel history for patients with symptoms of MERS and putting suspect or known cases under the full panoply of contact, droplet and airborne isolation precaution. Korea is in a catch-up mode, but presumably the index of suspicion is very high now and more rigorous infection control is place in the nation’s hospitals.

About 2,300 people have been placed under quarantine and nearly 1,900 Korean schools have been closed.