COVID EXIT STRATEGY—THE NUMBERS TO WATCH
“MOST RESEARCHERS AGREE,” Kai Kupferschmidt writes in Science, April 17, 2020, “that reopening society will be a long haul, marked by trial and error.” His article “The Lockdowns Worked—But What Comes Next?” discusses Covid-19 exit strategy. Here are tidbits on this important topic.
Kai Kupferschmidt, Berlin-born 1982, studied molecular biomedicine at the University of Bonn and then attended the Berlin Journalism School. He is a contributing correspondent for Science, the weekly magazine of the American Association for the Advancement of Science.
A Complex Path. Kupferschmidt writes, “As they seek a path forward, governments around the world must triangulate the health of their citizens, the freedoms of their population, and economic constraints.” He quoted epidemiologist Marc Lipsitch of the Harvard T.H. Chan School of Public Health: “We’ve managed to get to the life raft. But I’m really unclear how we get to the shore.”
Caroline Buckee, another epidemiologist at HSPH, said, “How to relax the lockdown is not something around which there is a scientific consensus.”
R-nought as a Goal. To epidemiologists (and, increasingly, to the rest of us) the letter R represents the number of people infected by an average infected person. That is, R3 describes an epidemic run wild: Each infected person gives the infection to three others. R0 (0 as in “nought”) describes the infected individual being successfully isolated; the injection is passed on to no one.
Kupferschmidt quotes Gabriel Leung, a epidemic modeler at the University of Hong Kong, who identifies the tools of regulating R: “isolating patients and tracing their contacts, border restrictions, and social distancing.”
See “Countering Covid-19—Worldwide Tactics,” here at SimanaitisSays for discussion of isolation, contact tracing, and social distancing. Noteworthy today is Kupferschmidt’s inclusion of border restrictions.
Closing Borders. The epidemiological argument for border closures is not to be confused with political, ethnic, or racial aspects. Here, it’s pure logic: Kupferschmidt quotes Alessandro Vespignani, a disease modeler at Northeastern University: “As soon as you reopen to travelers, that could be something that the contact tracing system is not able to cope with.”
Kupferschmidt observes, “… foreign visitors are generally harder to trace than citizens and more likely to stay at hotels and visit potential transmission hot spots.”
Social Distancing and Economics. Social distancing is effective at slowing the spread of Covid-19. “But,” Kupferschmidt notes, “it also comes at the greatest economic and social cost, and many countries hope the constraints can be relaxed as case isolation and contact tracing help keep the virus in check.”
However, as it’s said, “the devil is in the details.’’ Kupferschmidt notes that choosing a prudent path is difficult, in part because no controlled experiments have compared the effectiveness of different social distancing measures. He cites epidemiologist Lipsitch’s view: “I think there’s going to be a lot of experimentation, not on purpose, but because of politics and local situations. Hopefully the world will learn from that.”
Image from Science, April 17, 2020.
Suppress and Lift. “For now,” Kupferschmidt writes, “the most likely scenario is one of easing social distancing measures when it’s possible, then clamping down again when infections climb back up, a ‘suppress and lift’ strategy that both Singapore and Hong Kong are pursuing. Whether that approach can strike the right balance between keeping the virus at bay and easing discontent and economic damage remains to be seen.”
What’s required is continued research—and intelligent political response to these scientific findings. Kupferschmidt quotes Jeremy Farrar, head of the Wellcome Trust, who says, “Science is the exit strategy.” ds
© Dennis Simanaitis, SimanaitisSays.com, 2020