Dr. Allison McGeer of Mount Sinai Hospital in Toronto helped fight SARS in Canada and has been studying MERS. She doesn't see anything alarming about the spread of MERS yet. "As long as the virus hasn't changed, they'll be on top of it," she said.
As with SARS in Hong Kong, MERS spread in South Korea because doctors weren't looking for it, she said. It was February 2003, and the 64-year old Chinese doctor was in Hong Kong for a wedding. He checked into room 911 of the Metropole Hotel in Hong Kong. That room number gave rise to all sorts of conspiracy rumors because it was so reminiscent of the 9/11 attacks.
"The high rate of infection among guests staying on the ninth floor at the Hotel Metropole is remarkable because they did not have direct contact with the index case-patient," a team of experts wrote in the journal Emerging Infectious Diseases in 2013. The team included Dr. James Hughes, who worked on the SARS pandemic while he was at the Centers for Disease Control and Prevention and who is now at Emory University in Atlanta. People have studied the incident for years, interviewing everyone they can find who was there, but it's still not entirely clear how he managed to infect so many other people. But they included at least 20 other people:
A 22-year-old who'd come to Hong Kong to shop and who stayed at the Metropole before returning home to Singapore. That patient infected at least nine health care workers and 12 family members, three of whom died.
A Hong Kong resident who visited a friend staying on the 9th floor of the Metropole, who later infected 143 people at a Hong Kong hospital.
A business traveler who left the Metropole to go to Hanoi. A WHO expert, Dr. Carlo Urbani, treated this traveler, caught SARS, and himself died in Bangkok on March 29.
A 78-year-old Toronto woman who stayed at the Metropole and who died at home. She infected her son, who went to the hospital and infected at least 100 other patients, health care workers and visitors.
The infected doctor himself died March 4, 2003.
The Seoul case is similar. But just one person exposed to the MERS patient in South Korea is known to have traveled - a man who went to Hong Kong and mainland China who's since been isolated.
Some of the people the Seoul "patient zero" directly infected:
A 69-year-old man and a 73-year-old man who shared his hospital room
A doctor who treated him,
An 82-year-old man in the same ward but not the same room who later died
A 40-year-old man treated in the same hospital who was then sent to three more hospitals
A 45-year-old man who was visiting his father in the same hospital ward
A 59-year-old woman who cared for her husband who'd been in the same ward and
Some of these people in turn infected others, something known as tertiary transmission, including a 54-year-old man infected by his mother and a friend of his, who also visited the sick mom.
McGeer says big clusters of disease are not casual events. "It happens mostly in hospitals," she said. "You just have to be on top of it."
And even if a patient shows up in a hospital and no one thinks MERS at first, it usually does not lead to a lot of spread. It happed twice in the U.S. last year. One case was in Indiana, the other in Florida, and both men, healthcare providers who lived and worked in Saudi Arabia, contacted many other people while they were sick but did not infect anyone else. They both got better.
