Did Covid Kill The Flu?
The data sure do show a different landscape.
For the last year and a half we have all been drowning in a sea of articles about Covid. I’ve read about testing, tracking, lockdowns, masks and ventilators, healthcare worker burnout, overflowing hospitals, death, vaccines, more about masks, vaccine mandates, and the list goes on and on. But last year a very important piece of good news related to Covid seems to have been overlooked. Since the global lockdown in March of 2020 influenza has all but disappeared.
Tracking Influenza
Prior to Covid there was a well established seasonal pattern to influenza infections. For those of us in the northern hemisphere, roughly 90% of the world’s population, the season runs during the colder months from October through April. For the remaining 10% of on the other side of the equator, we see the same phenomenon during the months of April through September. Here is a look at influenza tracking from 2014 to 2019 broken down by hemisphere.
Do you see the seasonality? Notice the offset of peak numbers between the top and bottom halves of the globe? Those are the takeaways from this data. That’s how influenza used to look. Now take a look at the same data pooled for the globe and including the last year and a half.
After the spring of 2020, when governments around the world temporarily went on lockdown to slow the spread of Covid, influenza essentially dissapeared. The 2020–2021 season was one of the lowest on record. It seems obvious that masking, decreased travel, an increased hygiene might put a damper on the transmission of communicable diseases, but no one anticipated the level suppression that we saw last year.
Moving forward in uncertainty
So did Covid kill the flu? Do we have one less thing to worry about? Sadly the answer to both is no. The dormancy of influenza and other communicable diseases was temporary and cases will once again rise as the world continues to move (I hope) back towards a state of normalcy. In fact, doctors are worried that we may face a ‘twindemic’ this winter. A disastrous scenario where a Covid surge and influenza season peak at the same time. But I am ever hopeful. There was fear of a twindemic last year and thankfully that never came to pass. We have effective vaccines for both diseases and the data from last year’s non-existent flu season seem pretty clear to me. We can even stop the spread of flu. If we want to.
