Where Has Influenza Gone?

If you’re an infectious disease geek — and who isn’t these days? — you may have noticed that the Centers for Disease Control and Prevention (CDC) have not sent out any alerts over influenza this influenza season. (In the United States, influenza season is from October to May.) In fact, if you look at CDC’s influenza surveillance reports, it seems that influenza has all but disappeared. You can even drill-down on the data further and see that influenza is active at very low levels across all age groups. So where has influenza gone?

Influenza has not really gone anywhere. It is still present in the community. What is happening is that we as a country — and at the direction of public health officials — have taken considerable steps to prevent the spread of the novel coronavirus, a respiratory virus that is transmissible in similar ways to influenza. Control one, and you control the other respiratory diseases.

It’s not just influenza, however. The Respiratory Syncytial Virus (RSV) is another respiratory virus that has all but disappeared from radar during the pandemic. Unlike coronavirus, RSV is a respiratory infection that tends to be more severe in infants and cause more of a head cold-type of syndrome in healthy adults. There is no current vaccine against RSV, but there are encouraging advancements in vaccine development against it, especially now with mRNA technology becoming more available and understood.

So why not just wear masks in the winter to prevent the 12,000 to 61,000 annual deaths from influenza? Well, that has always been an option. Many cultures around the world wear masks at times of the year when influenza is active. It’s not as if covering coughs and sneezes (which spread diseases) is a novel idea that we in the West came up with just last year. Or maybe it’s new to the West?

Perhaps the “new normal” that is expected after the pandemic will bring with it a normalization in the United States of wearing cloth face masks when local epidemics of respiratory diseases are declared. Perhaps the mRNA vaccine technologies are used for a universal influenza vaccine. And perhaps, just perhaps, the political divisions and lack of agreement on what constitutes a fact will subside enough to allow public health and medical experts to do their work and continue to save lives.

Author: René F. Najera, DrPH

I am the editor of the History of Vaccines site, an online project by the College of Physicians of Philadelphia. All opinions expressed on these blog posts are not necessarily those of the College or any of my employers. Check out my professional profile on LinkedIn: https://www.linkedin.com/in/renenajera Feel free to follow me on Twitter: @EpiRen