New research suggests 10 times more Minnesotans might have been infected with COVID-19 than we know of. Here’s why that’s good news.

On Tuesday, the British newspaper The Independent reported:

In Minnesota’s case, where we have 47,452 cases as of Monday according to the Department of Health, that would mean 470,452 Minnesotans have or have had Covid-19. That is 8.3% of the population, the vast majority of them without knowing they were infected – they are ‘asymptomatic’. When tests were conducted at the JBS plant in Worthington for example, 239 of the 2,000 staff tested positive. They didn’t know they had had the disease until they got the test result.

This might not sound like good news but it is, and for two reasons. First, it means that the state – and the country – is closer to ‘herd immunity’ than we thought, though possibly still some way off. Second, it means that the disease is less deadly than we thought.

As I’ve written previously, the true measure of how deadly a disease is the Infection Fatality Rate (IFR) which is the share of those infected with a disease who die from it. We cannot calculate this, however, without knowing how many people have been infected. Dividing the number of deaths by the number of diagnosed cases doesn’t help. This gives you the Case Fatality Rate, which might give you some idea of how effective your treatments are, but using it to assess how deadly the disease is, given the large number of asymptomatic infections, is like trying to assess how dangerous driving is by calculating the share of people who survive care crashes.

If it is the case that 470,452 Minnesotans have been infected with Covid-19 and 1,545 have died from it, then that gives an IFR of 0.3%. In other words, if you get it you have a 99.7% chance of surviving. Of course, this varies greatly by age and takes no account of the lasting effects on those who are infected. This compares to 0.1% for seasonal flu and is just below the bottom of the range of estimates for Covid-19, 0.5–1%.

There is, it seems to me, a strange tendency for some to react badly to any good news relating to this epidemic. The only news these folks will accept is news that supports further measures like lock-downs, school closures, or mask mandates. But if we are being led by ‘the science’ and ‘the data’, we ought to follow it even when the direction it leads is a positive one.

John Phelan is an economist at the Center of the American Experiment.