What should we make of the near elimination of flu in Minnesota?

Last Thursday brought some welcome good news for Minnesota on the medical front. The Department of Health’s most recent ‘Weekly Influenza & Respiratory Illness Activity Report‘ showed that this current flu season continues to be one of the best on record, with hospitalizations well down on most previous years, as Figure 1 shows. What can we attribute this to?

Figure 1:

Source: Department of Health

Logically, it would seem that there are two possibilities. One, is that the number of people suffering with seasonal flu isn’t down – or at least isn’t down by that much – but that they are not being picked up in the numbers for some reason. The second possibility is that flu numbers really are down, lowered by the measures taken to slow the spread of Covid-19.

Are seasonal flu hospitalizations being counted in Covid-19 numbers?

There could be something to the first of these. As I wrote last week, and as Figures 2 and 3 show, the recent surge in both ICU and non-ICU hospitalizations in Minnesota with Covid-19 was matched, to a large extent, by a fall in the number of both ICU and non-ICU hospitalizations without flu. As I wrote in November:

On the face of it, this seems strange. Why should non-Covid-19 hospitalizations be taking such a sharp fall? We are heading into flu season which typically sees hospital admissions rise, putting great pressure on hospital capacity even in years without Covid-19 to contend with. Why is this year so different? My guess is that many of these Covid-19 ICU hospitalizations are ones which would have occurred anyway given the usual seasonality, but are being logged as Covid-19 hospitalizations this year.

Figure 2: ICU hospitalizations in Minnesota, seven day moving average

Source: Department of Health

Figure 3: Non-ICU hospitalizations in Minnesota, seven day moving average

Source: Department of Health

This is not to suggest that the numbers are being ‘cooked’. I have little doubt that the patients being logged as infected with Covid-19 are so infected. But it does put the ‘surge’ in Covid-19 hospitalizations into context. As so much of this surge was offset by declines in non-Covid-19 patients, our overall hospital capacity was not strained to the extent that a focus on the Covid-19 numbers, which drove some of the more hysterical reporting, would suggest.

Have masks and social distancing killed the flu?

As I wrote in December, another argument is that the measures taken to slow the spread of Covid-19, such as mask mandates, lockdowns, and social distancing, have wiped out the flu as a welcome side effect. This is an intriguing argument with two important lessons, if true.

First, it shows that Minnesotans must have been following Gov. Walz’ orders. This confirms other data, and gives the lie to the notion, shamefully put about by some in the administration, that their measures have had little success slowing the spread of Covid-19 because of Minnesotan’s non-compliance.

Second, it shows that measures like mask mandates, lockdowns, and social distancing have much less effect on the spread of Covid-19 than their boosters admit. When he announced the mask mandate, for example, Gov. Tim Walz said:

“If we can get a 90 to 95% compliance, which we’ve seen the science shows, we can reduce the infection rates dramatically, which slows that spread and breaks that chain”

We have had those levels of compliance in Minnesota for an extended period and still had a surge in cases.

So how do we account for the success of these measures against the flu while Covid-19 raged? The argument then is that these measures are more effective against the flu because it is less contagious. But that simply proves the point: the flipside of that argument is that the measures are less effective against Covid-19 because it is more contagious.

This is not to argue that these measures are not worth pursuing. But we ought to be realistic about what they can actually accomplish. Hitherto, frankly, their efficacy has been grossly oversold. By painting them as the difference between life and death, policymakers have cranked up tensions and made a sensible analysis much more difficult. It seems likely, in fact, that they only have much impact at the margin. That might still be enough to justify them.

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