nights, she and a female friend had shared room 938 at the Metropole, about twenty steps from Professor Liu’s room.
Back home in Singapore, Mok’s fever lingered and she developed a cough. On March 1 she consulted doctors at Tan Tock Seng Hospital, a large public facility housed in gleaming new buildings just north of the city center. After a chest X-ray showed white patches on her right lung, Mok was admitted under a diagnosis of atypical pneumonia. One of the doctors who saw her was Brenda Ang, a senior consultant for infectious diseases, who happened also to be in charge of infection control at Tan Tock Seng. There was no particular alarm about infection control, though, when Esther Mok brought her condition to the hospital. “At that time,” Brenda Ang told me later, “we didn’t know what it was.”
Ang agreed to take me through the story from memory, half a dozen years after the events, and though she warned that her recollections might be patchy, on many points they seemed rather precise. We met in a conference room within a small, detached structure on the landscaped grounds of Tan Tock Seng; it was a room that served intermittently for staff meetings and as a classroom for medical students on rounds, but we had it for an hour. Ang was a tiny, forthright woman in a lilac print dress. Observing medical discretion, she didn’t use Esther Mok’s name but spoke instead of “a young lady” who had been “the first index case.” In her role as infectious disease consultant, Dr. Ang had seen the first index case herself. She was assisted by her registrar (a younger doctor in specialty training), who took a mucus sample from Mok for culturing. The registrar wasn’t wearing a mask, Ang told me. No one at Tan Tock Seng was masked against this infection at the start, but unlike Ang herself, the registrar got sick.
His case, with some dramatic complications, unfolded later. In the meantime, Ang and her colleagues dealt with Esther Mok’s worsening pneumonia, unaware that the young woman was becoming another superspreader of this disease that had not yet been identified or named.
At first Mok was placed in an open ward, with closely spaced beds, in proximity to other patients and staff members coming and going. After a few days, now gasping for air, she was transferred to the Intensive Care Unit. It seemed unusual, Ang told me, for such a young person to be struck by pneumonia so severely—unusual enough that, on the Friday of that week, when doctors from the other Singapore hospitals visited Tan Tock Seng for weekly grand rounds, Ang and her colleagues presented the atypical pneumonia case for discussion. Having heard the symptoms and the history, one doctor from Singapore General Hospital spoke up, saying, That’s odd, we have an atypical pneumonia case too, another young woman, and she too has recently returned from Hong Kong. With a little checking, they learned that the Singapore General case was Esther Mok’s friend, who had shared room 938 at the Metropole. This brought a moment of chill recognition.
In coming days, more atypical pneumonias arrived at Tan Tock Seng, most or all of them with connections to Esther Mok. First was her mother. Three days later, the pastor of her church, who had visited Esther at the hospital to pray, came back as a patient. Then her father showed up, suffering a cough with blood-streaked sputum. Then her maternal grandmother, then her uncle. By midmonth they were all patients at Tan Tock Seng. And as the Mok family cluster began to generate alarm, another bit of ominous news reached Brenda Ang. It was Thursday, March 13, when an administrative assistant informed her that four nurses from Mok’s original ward had called in sick. Four nurses out sick on one day—that wasn’t anywhere near within the boundaries of normal. “Defining moment for me,” Ang said dryly, as I sat before her scribbling notes. “Everything was accelerating.”
And related events were accelerating worldwide, not just at Tan Tock Seng—though Ang and her colleagues didn’t yet know it. In Geneva, at almost precisely the same time, WHO issued its global alert about a “severe, acute respiratory syndrome of unknown origin.” Officials at Singapore’s Ministry of Health were soon in the loop, made aware that three cases of atypical pneumonia (Esther Mok and her friend, plus another) had turned up at once, all traceable to Hong Kong’s Metropole Hotel. That put Mok’s case into a much larger