SEJONG, SOUTH KOREA—South Korea's Ministry of Health reported 12 new confirmed cases of Middle East respiratory syndrome (MERS) and one additional death today, bringing the total to 138 cases and 14 deaths. But a joint mission of international and local health experts expressed cautious optimism that the country may be turning the corner on the outbreak, although its members emphasized the need for continued surveillance and attention to infection control.
At a press conference here today, the team urged South Korean officials to reopen more than a thousand schools closed because of MERS fears. Transmission in schools “has not been a feature of this outbreak; on the other hand, the closure of schools creates levels of fear and concern not [based on] a real reflection of danger,” said panel member Keiji Fukuda, assistant director-general for health security at the World Health Organization (WHO). Local press reports say most schools will resume classes on Monday, though in some Seoul districts the final decision will be up to individual principals.
The joint mission, by WHO and South Korea's Ministry of Health, brought together eight visiting and eight Korean experts in infectious diseases, epidemiology, and related specialties to study what is by far the largest outbreak of MERS outside the Middle East. The experts agreed that the outbreak caught the South Korean health sector by surprise and that authorities stumbled in their initial response. "There are things that could have been done better," said Jong-Koo Lee, a medical doctor and public health expert at Seoul National University who led the South Korean side of the team. But the government has recovered its footing. "Those steps needed to control this outbreak are being put in place and strengthened on a very rapid basis," Fukuda said.
The vast majority of MERS cases has occurred inside hospitals, the team noted—not in people’s homes, public transport, restaurants, or other public places. One patient was an ambulance driver who apparently became infected after transporting two MERS patients; and in one case, confirmed on Friday, “we just haven’t yet found the link to an existing patient,” Lee said. Although Fukuda said he wouldn't be surprised to see MERS transmission within a household, or even in the wider community, “we just don’t see it yet,” he said. The epidemiological pattern in South Korean is similar to what has been seen in Saudi Arabia, Fukuda added.
One factor that may be unique to South Korea, however, is the practice of "doctor shopping." The initial patient, who fell ill after returning from a business trip through several Middle East countries, visited four clinics and hospitals before being diagnosed with MERS on 20 May. Such behavior increases the chances of viral spread.
The panel did not address the utility of wearing facemasks outdoors and in public places, which many Koreans began doing after the outbreak started. Asked after the meeting by ScienceInsider, Fukuda said that the practice makes little sense, because “your chance of getting MERS on the street is incredibly low. … But if it makes people feel safer, I don't see any harm," he added. (In hospitals, however, wearing facemasks is an essential part of preventing the spread of the virus through droplets.)
There are still puzzles in the transmission chain. Some of those who contracted the virus were only on the same floor as a MERS patient, not in the same room. Korean investigators are conducting experiments looking at how droplets spread, and what effect contamination of the environment and poor ventilation might have had. "It is not crystal clear if these factors are playing a role or not," Fukuda said.
In sequencing studies available so far, "we do not see any changes that appear to have made the virus itself more transmissible," Fukuda said. The sequence of the Korean virus hasn't been made public; Fukuda did not explain the delay but said he expected it to be posted publicly "as soon as possible." (The sequence of a Korean patient who was diagnosed with MERS after traveling to China was posted in GenBank last week by Chinese researchers.)
The mission's other recommendations include strengthening infection control measures in health care facilities, asking all patients presenting with fever or respiratory symptoms about possible contacts with a MERS patient and their travel history, continuing to trace contacts, and ensuring that suspected cases do not travel.
The group warned that what happened in Korea could occur elsewhere. "This is the global challenge of modern times: An infection anywhere in the world can now appear anywhere in the world very quickly," Fukuda said.
*Update, 14 June, 8:15 a.m.: The paragraph about facemasks has been added to this story.