No one knows. However, the Global Policy Laboratory at UC Berkeley estimates that shutdowns prevented 60 million infections in the U.S. Its model does not estimate how many lives were saved, but if one assumes a fatality rate of 1 percent, 60 million infections translates to 600,000 lives.
Meanwhile, a study by the Imperial College London estimates that shutdowns saved about 3.1 million lives in Europe. This includes 500,000 lives supposedly saved in Britain.
Mention of the Imperial College reminds us that we shouldn’t take the estimates in models like these very seriously. The Imperial College estimated that, with the shutdown in place, deaths from the Wuhan coronavirus in the UK would not exceed 20,000. As of now, the British death toll is just over 40,000.
What do the two new models assume about how people would have behaved absent the shutdowns? It looks like the Berkeley model assumes people would have taken few, if any precautions.
According to this report in the Washington Post, the Berkeley model used as its starting point the rate at which the virus was spreading in the initial days after it was seeded in the countries studied. But in those first few days, people weren’t taking basic precautions such as washing their hands, etc.
It’s irrational to assume that, as time went on, people would have continued behaving the same way. Many, especially those in high risk categories, would have changed their behavior substantially and quickly absent the shutdowns. I changed mine three weeks before the Maryland shutdown.
Unless a model takes this reality into account, it cannot reliably measure the impact of shutdowns. But taking this reality into account requires so many assumptions as to render a model mostly guesswork. Or so it seems to me.
The same problem arises when one tries to assess the economic impact of shutdowns. It’s unrealistic to assume that, in the face of rising infection and death numbers, people would have behaved in a way that allowed the economy to keep purring along. But no one knows the degree to which people would have altered their behavior. Thus, we can’t reliably quantify the economic impact of the lockdowns — only the economic impact of the virus.
Finally, I should note that the estimates of infections prevented and lives saved are as of today. Jennifer Nuzzo, an epidemiologist at Johns Hopkins told the Post:
The lockdowns were a pause button, not a cure. Any reduction in the occurrence of cases or deaths is temporary.
She may be right, at least up to a point.
Nuzzo also said that the economic and social harms of shutdowns are considerable,so that societies at this point need to transition to a more focused strategy built around testing, contact tracing and isolation of coronavirus patients. I think she’s definitely right about that.