We are embarked on a policy path of opening things up without major complementary measures, an approach based more on wishful thinking than on logic or evidence. In guidance issued last month, the Trump administration stated this relaxation should only begin when the number of new cases daily had declined for 14 days. This criterion has not been met for the country as a whole or in many states, yet reopening has begun.
A simple calculation illustrates why this path is so dangerous. The most important parameter for understanding an epidemic is what epidemiologists label R0 (R-nought) — the number of people infected by a single individual with the virus. If R0 is greater than 1, an epidemic explodes; if it is less than 1, it diminishes and eventually ceases to be a problem. Experts estimate that before lockdown R0 was about 2.5, which is why lockdown was necessary. They now estimate, in part because case counts have been stable, that R0 is a bit below 1 — perhaps 0.9 or, on an optimistic view, 0.8.
Basic but grim arithmetic implies that if we move from lockdown even 20 percent of the way back to normal life, the epidemic will again be potentially explosive. (For example, if we are currently at an R0 of 0.9, and assuming that the R0 without any distancing is 2.5, then returning to 20 percent of normal would take the R0 to 1.22, clearly in the danger zone.) This is very worrying as the president and many other political leaders seem to be encouraging substantial reversals in lockdown policies.
It’s conceivable this will work out, at least in the short run. For a few months, summer heat and humidity may reduce transmissibility. The virus may mutate in benign ways. The population that has not yet been infected may be less susceptible on average to the virus and less contagious when they catch it.
But don’t count on it; hope is not a strategy. These factors have been operating in recent weeks, and yet R0 has remained stubbornly close to 1. That suggests it is unlikely that any of these factors are significant enough to change the basic conclusion: Substantial opening up without new measures to reduce transmission is likely to unleash major new waves of disease, sooner or later.
Some might believe this is a price worth paying for the economic benefits the country would reap. After all, on a rough estimate covid-19 is reducing the gross domestic product by 20 percent — $80 billion dollars a week. The problem is that the main constraint on economic activity is not mandatory lockdowns. Rather, whatever is technically permitted, people will be reluctant to resume normal behavior for fear of being infected. The likely result: a resurgent pandemic, dramatically lowered economic activity, or both simultaneously.
Moreover, this economic slowdown is a price we do not have to pay. We could substantially reduce transmission, save lives and permit the safe acceleration of reopening — if we are willing to commit the necessary resources. These would be small compared to the economic damage the virus is wreaking and the amounts we are paying to try to compensate for the losses.
The most promising strategy is establishing a system of pervasive targeted testing. If we were able to identify individuals who have potentially been infected, then quarantine those who test positive, we could substantially reduce the transmission rate. Suppose this required testing every American every week and that each test cost $20. (Both are pessimistic assumptions.) The $6.6 billion price tag would be less than one-tenth of the weekly cost of the Cares Act.
Similarly, investments in contact tracers for those who identified with covid-19 would have an extraordinarily high return. Suppose the total cost of a contact tracer is $400 daily, and that 300,000 tracers are needed to follow up on all newly discovered positive cases. The cost would only be $600 million a week, less than 1 percent of the cost of the Cares Act.
The same kinds of calculations make the case for much more spending on masks, on potential therapies and on pursuing production of plausible but still unproven vaccine candidates.
Amounts of money that are small compared to the economic losses we are suffering are immense relative to battling the virus. They should be the first priority going forward.
Lawrence H. Summers is a professor at and past president of Harvard University. He was treasury secretary from 1999 to 2001 and head of the National Economic Council for President Barack Obama from 2009 to 2011.