Need another reason to wear your mask? It’s essentially wiping the floor with the flu.

Two for the price of one

As winter draws near in the northern hemisphere, it’s full spring in the southern hemisphere. The flu season has come and gone in the south, but the flu was almost nowhere to be seen.

It was always expected that COVID-19 measures would also protect against the flu — after all, the viruses spread in largely the same way — but the scale at which this is happening is remarkable.

“Never in my 40-year career have we ever seen rates … so low,” says Greg Poland, an influenza expert at the Mayo Clinic.

In New Zealand, there’s been a “near extinction of influenza”, with the number of cases decreasing by 99.8%. The COVID-19 response has essentially eliminated the flu, reducing overall mortality by about 5% — when normally, overall mortality would increase in the winter.

New Zealand is far from an isolated example. The entire area of Oceania exhibited a similar trend, and in South America, the flu season was also very mild. Claudia Cortés, a doctor in Chile, said although physicians “keep checking for the other viruses … all we’re seeing is [Covid-19].” She added, “We were surprised by the decline in the other viruses like influenza. We never dreamed it would practically disappear.”

Some speculated that this is merely an illusion — people are scared about the pandemic and they’re hesitant to get tested for the flu, but this isn’t the case. The positivity rate of flu tests has also gone down dramatically (from 5-10% in a typical season to 0.1% now, according to WHO data).

“This [decline] surprised me,” Sylvain Aldighieri, deputy director of the Department of Health Emergencies at the Pan American Health Organization, said. “We were expecting a double burden of cases, because in countries like Chile and Argentina, the flu winter epidemic places a high burden on healthcare services.”

This is development it so surprising it wouldn’t have even been considered possible a year ago, and researchers now suggest that these containment measures could also be used in the event of a large flu outbreak.

But what does this mean for the upcoming flu season?

A reason for both optimism and caution

We may enjoy a flu season that’s milder than what we were expecting.

In North America, the flu season ended abruptly in March (although it typically lasts through April). Now, as the new flu season is starting to kick into gear, the flu is still at very low rates, not just in North America, but in Europe and Asia as well. Judging by this and by what we’ve seen from the south, it seems that this year’s flu season could spare the world of the brunt of its damage — this was a huge concern for many health officials who feared that the flu toll would pile over the COVID-19 one.

But there’s a threat hidden in this good news: the exceptional measures that the world took are enough to keep influenza, one of the most contagious respiratory diseases, at bay. But they’re not nearly enough to do the same thing for COVID-19.

So while we may be largely spared by the flu, we’re in for a hell of a COVID-19 winter.

Sure, New Zealand is widely hailed as an example in this pandemic, but other areas in the southern hemisphere haven’t been doing nearly as well. Just look at South America, where COVID-19 cases have surged dramatically even as the flu stayed historically low. We’re seeing a second (or even third) COVID-19 wave sweep through the northern hemisphere, in part due to changing weather, but more due to pandemic fatigue — people are tired of prevention measures and want things to return to normal.

Ultimately, if North America and Europe want to stop flu outbreaks in their tracks, the best thing to do (this year at least) is to keep pressing the coronavirus prevention measures.

It won’t be easy, but it can be done — we’ve already seen it happening in half of the globe.