What Singapore’s and Hong Kong’s success is teaching us about the pandemic.








Consider a couple of data points. Singapore so far appears not to have had a single recorded health-care-related transmission of the coronavirus, despite the hundreds of cases that its medical system has had to deal with. That includes one case reported this week of a critically ill pneumonia patient who exposed forty-one health-care workers in the course of four days before being diagnosed with covid-19. These were high-risk exposures, including exposures during intubation and hands-on intensive care. Eighty-five per cent of the workers used only surgical masks. Yet, owing to proper hand hygiene, none became infected.


Meanwhile, the strict policy has been threatening to close entire emergency departments. So, out of necessity and based on the early evidence, public-health authorities in San Francisco have loosened restrictions, letting exposed employees stay at work as long as they wear a surgical mask and don’t have symptoms. At least one hospital in Seattle is now following a similar policy, with the support of state public-health officials and the C.D.C. Other hospitals across the country will likely soon follow. The factors that appear to be important in protecting health-care workers from the disease have been insuring meticulous hand hygiene and cleaning; restricting clinics and hospitals to necessary patient visits; shifting as much care as possible to virtual channels (such as phone and video); and applying standard droplet precautions (surgical mask, gloves, and gown) with respiratory patients.

For those who cannot stay home, the lesson is that it is feasible to work and stay coronavirus-free, despite the risks. Deborah Yokoe, the medical director of hospital epidemiology and infection prevention at U.C.S.F. Medical Center, told me that, given the safety practices in the hospital, she is seeing a greater likelihood of staff picking up infections at home than at work. Following this logic, San Francisco public-health officials are pushing medical facilities to have all health-care workers—not just those who have had patient exposures—report whether they have fever or flu symptoms prior to starting work each day.

In South Korea, the success of mass testing in containing the spread of the disease has raised the possibility that asymptomatic carriers were causing outbreaks. But another implication of the experience in Singapore and Hong Kong is that these essentially invisible cases of the coronavirus may not be driving as many serious infections as some scientists have projected. Health officials there did not conduct mass testing of the population to look for infected people without symptoms. They focussed on aggressively searching out and testing only those who developed suspicious symptoms or had high-risk exposures in the community. They accepted that the virus might circulate among people who notice nothing. Yet their strategy brought cases under control.

There are a number of possible explanations for this. One is that truly asymptomatic cases—people who never develop symptoms that would prompt evaluation—may be less common than feared. In Wuhan, where testing became widespread and more than seventy-two thousand coronavirus cases were identified, just one per cent never developed symptoms. Aboard the Diamond Princess cruise ship, where, following an outbreak, more than three thousand passengers and crew were quarantined and tested—allowing one of the most complete evaluations of any affected population—six hundred and thirty-four people proved to have the virus. Most had no symptoms at the time of testing, but they proved to be pre-symptomatic: over several days, they developed recognizable signs of the disease. Just eighteen per cent were persistently asymptomatic.



Source: newyorker.com