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Lockdown can’t last forever
We need to hit and release the brakes on physical distancing, again and again, until we safely get to immunity. To see us through the next year or more, all citizens must prepare for several cycles of a ‘suppress and lift’ policy
Lockdowns, quarantines and extreme forms of physical distancing work: They are curbingthe spread of COVID-19. But they cannot last indefinitely, at least not without causing enormous
damage to economies and compromising peoples’ goodwill and emotional well-being.
When governments decide to close schools (or not), for example, they are implicitly trying to balance these various interests. One major problem, though: Their calculus about the underlying trade-offs typically is unclear, and the criteria for their policy adjustments are unknown.
A formal framework is needed, with an explicit rationale grounded in science, for determining when and how and based on what factors to relax restrictions — and how to reapply some or all of them should another epidemic wave hit again. Containment has failed everywhere. In some places — Wuhan in February; northern Italy in March — the epidemic spread so quickly that the relevant authorities had to focus mainly on mitigating its effects, on damage control.
In other places, suppression has worked so far: Hong Kong, Singapore and Taiwan have not experienced sustained local epidemics. Not yet, at least. But in the many more places now in the throes of full-on epidemics, notably in the US and Western Europe, the pressing concern is how to suppress the virus’s spread so as to avert a Wuhan-like health disaster, but without destroying economies or undermining people’s resilience and their willing consent to very taxing social-distancing measures.
The first objective of any response anywhere must be to protect lives, and that means averting the collapse of the health care system. Hospitals are the last line of defense. When their capacity to handle emergencies is overwhelmed — as in Bergamo, northern Italy, or in areas of Spain — there is little point theorising as I am about to: All one can do then is to roll up one’s sleeves, hook up patients to intravenous drips and ventilators, and try to save as many lives as possible with whatever means are available. But past that point, the ultimate objective must be to bring the epidemic down to a slow burn so as to buy time for the world’s population to acquire, one way or another, immunity to COVID-19.
The pandemic can only be prevented from resurging when at least half the world’s population has become immune to the new virus. And that can happen in only one of two ways: After enough people have been infected and have recovered, or have been inoculated with a vaccine. Allowing the first option to happen, unmitigated, would be a humanitarian catastrophe: It would mean many deaths, mostly among the elderly and poor people with limited access to healthcare. The second option — developing a safe, effective vaccine and making enough of it for everybody — is a goal at least one year, perhaps two years, away.
Massive lockdowns and distancing measures cannot be sustained that long. Note that it is very unlikely that any large community has acquired sufficient herd immunity to the novel coronavirus yet, even where it has hit hardest. Nor do we have enough information about the people known to have been infected and to have recovered so far — that’s why it is so urgent to conduct serology, or blood work, to study how many people in countries that have already experienced a first wave of infections, like China and South Korea, are producing antibodies. To see us through the next year or more, we must all prepare for several cycles of a “suppress and lift” policy — cycles during which restrictions are applied and relaxed, applied again and relaxed again, in ways that can keep the pandemic under control but at an acceptable economic and social cost. How best to do that will vary by country, depending on its means, its tolerance for disruption and its people’s collective will. In all cases, however, the challenge essentially is a three-way tug of war between combating the disease, protecting the economy and keeping society on an even keel.
Here is a formal framework for how governments could monitor the state of this pandemic much more accurately than many seem to be doing now, and how then, acting on the evidence, they could tune their interventions quickly enough to stay ahead of the outbreak trajectory. For starters, one needs robust data. Policy must not be determined based on the daily count of reported cases — the tallies you read about constantly in the news — because those are unreliable. What’s needed instead is the coronavirus’ real-time, effective reproduction number, or its actual ability to spread at a particular time. And one needs to understand that number properly, in context.
Daily reported cases do not convey the true state of the virus’s spread. For one thing, there is so much heterogeneity in the per capita testing capacity of countries around the world that it would be foolhardy to try to draw any broad conclusion about the virus’s transmissibility from all that disparate data. For another, the figures for reported cases lag actual infections by at least 10 to 14 days. That’s because the incubation period for COVID-19 is about six days. And because — partly given shortages of test kits in many countries — some people don’t ever get tested, and those who do probably don’t until they have displayed symptoms for a few days.
In China, the location-based functions of the online payment platforms of Alibaba, Baidu and Tencent could be used to track people’s activity. In the West, data feeds from Facebook and Google could geo-code online searches and payments. Citymapper, a mapping and public transit app, follows people’s movements in major cities in real time.
Activity data mined from all these apps and platforms, as well as records from payment cards, could be used to determine how people mix — which in turn could be used to infer the likelihood of their passing the virus around. With a bit of ingenuity, existing digital tools can quickly be turned into epidemic-monitoring instruments — and without intruding into people’s lives. And how long can the population accept the restrictions required to maintain that level of infections? Will people stop complying? Are their mental and emotional well-being being jeopardised?
And yet, even though different communities will strike a different balance between these interests, the “suppress and lift” strategy is generalizable to all. Trying to see our way through the pandemic with this “suppress and lift” approach is much like driving a car on a long and tortuous road. One needs to hit the brakes and release them, again and again, to keep moving forward without crashing, all with an eye toward safely reaching one’s final destination.
— Dr Leung is an infectious disease epidemiologist and dean of medicine at the University of Hong Kong. NYT© 2020
The New York Times