Are ‘Immunity Debt’ Claims After Covid-19 Precautions Accurate Or Misinformation?

Some are now claiming that you, especially if you are a kid, may have some debt. In this case, they’re not talking about the shouldn’t-have-traded-on-the-FTX-crypto-exchange-as-a-five-year-old kind of debt. No, there are claims that you may have what’s being called “immunity debt” from Covid-19 precautions like face mask wearing. The assertion is that not being exposed to respiratory viruses over the past two years has left your immune system “out of practice” and thus weaker. And having such supposedly weaker immune systems is supposedly leaving many people more susceptible to viruses like the respiratory syncytial virus (RSV), hence the current surges in such pathogens. So is there any truth behind such claims? Or are they yet another attempt at railing against face masks, social distancing, and other “inconvenient” Covid-19 precautions that you can do to, you know, help your fellow humans not get sick and die?

Well, David R. Stukus, MD, a Professor of Clinical Pediatrics in the Division of Allergy and Immunology at Nationwide Children’s Hospital, called “immunity debt” a made-up term:

Others on Twitter, such as @TRyanGregory, @19joho, and @DeviJustice pointed out some logical shortcomings with the “immunity debt” argument:

On balance, such “immunity debt” claims presume that your immune system is very much like a muscle, that it’s something that needs to be constantly kept in use to remain strong or otherwise may atrophy. Well, your immune system ain’t a muscle as Colin Furness, MISt PhD MPH, Assistant Professor of Information at the University of Toronto tweeted:

Your immune system can’t pick up your underwear after you’ve accidentally chained your thong to a bowling ball. You can’t really stare at your immune system in the mirror or post a picture on Tinder of you flexing your immune system and saying, “look at me. I’m eating dirt and will still be able to make our date.”

More importantly, you don’t have to keep exposing your immune system repeatedly to different pathogens to keep your immune system strong. If this were indeed the case, medical doctors would be telling patients, “make sure that you get sick as much as possible, so that you don’t get sick.” That would be kind of paradoxical. And you don’t want to be walking up to strangers and saying, “you look like you have runny nose. Can I lick your face?”

No, your immune system is more like a brain than a muscle, assuming that you aren’t muscle-headed, so to speak. Typically, your immune system isn’t like that forgetful blue fish in the movie “Finding Nemo,” that who-am-I Matt Damon character in the movie “The Bourne Ultimatum” or that short-term-memory Drew Barrymore character in the movie “50 First Dates.” A normal immune system can have a darn good memory.

Plus, as Jessica Steier, DrPH, creator and co-host of the Unbiased Science Podcast, described in the following tweet and video (which would presumably be a tweedeo), your immune system is constantly working behind the scenes no matter what you are doing:

It’s not as if wearing a face mask or staying a Harry Styles height (that’s six feet) away from others is going to prompt your immune system to go on vacation to Tahiti. It has continued to clean up junk and make repairs in your body each and every day.

Sure, your immune system may not have yet built up protection against something totally new that it’s never seen before like the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) prior to the Covid-19 pandemic. However, by the time you’ve reached your terrible twos, chances are your immune system has already seen a whole lot of different pathogens via your mom, vaccination, or natural exposure. And like dating a horrible significant other, being exposed to some part of a nasty pathogen can leave some indelible memories. That’s why once you’ve completed your primary series of measles, mumps, rubella, hepatitis B, and other such recommended childhood vaccinations, you don’t have to keep getting vaccinated against such pathogens again and again every year.

One set of notable exceptions are respiratory viruses with high mutations rates like the flu and the SARS-CoV-2. For example, the dominant strain of influenza keeps ch-ch-changing each year. Each time the influenza virus uses the cells in your body to reproduce, it can make mistakes as if it were someone taking a selfie on a see-saw. This can result in new versions of the virus that are slightly different from the original and thus perhaps not quite as easily recognizable by your immune system. Over time newer and newer versions of the flu virus can look increasingly different from what’s circulated and been in flu vaccines in previous years. This phenomenon has been dubbed antigenic drift, meaning that the recognizable proteins on the surface of the virus called antigens gradually change over time. This is one of the reasons why each year you should get flu vaccines with updated influenza virus strains in them. This is also why getting the flu one year (such as in 2020) probably won’t offer you enough protection in subsequent years.

Now, the current surge in RSV among those under two years of age may be due in part to the fact that some very young children are seeing RSV for the very first time now. Many of the current cases may be accumulated cases that would have been spread out more evenly over the Fall 2020 through late Winter 2022 time period had Covid-19 precautions not been in place. It’s true that your immune system typically has to see a pathogen at least once before generating a more proper, organized response. Otherwise, the first time your immune system sees a pathogen, it can behave a bit like a virgin would on a first date, firing off in random directions and laughing far too much at its own jokes. So there could be more RSV virgins around in 2022 than in other pre-2020 years.

This would not be the same as an “immune debt” and doesn’t provide a viable argument against implementing Covid-19 precautions among those older than two years of age. Again, school-aged children and adults have already been exposed to a lot over their lifetimes. (Imagine a five-year-old saying, “the things that I’ve seen.”) Those older than two years of age don’t need constant exposure to pathogens to maintain their immune systems.

So what might explain the current surge in respiratory viruses? The loosening of Covid-19 precautions in 2022 is certainly allowing respiratory viruses to spread more unfettered now. There’s no indication that Covid-19 precautions over the past two years have somehow made the surges now worse than they would have otherwise been. What’s happening with respiratory viruses can naturally cycle between worse and better from year to year. For the flu, this can depend largely on how many people get the flu vaccine and how well the influenza virus strains in the vaccine match those that are circulating that season.

The Covid-19 pandemic may be affecting other respirator viruses in three key ways. One is the co-infection and weakened by Covid-19 problem, which is not quite the same as co-dependency. When your immune system is busy and exhausted fighting the SARS-CoV-2, it may be less able to fend off other respiratory viruses. Moreover, even after you’ve recovered from Covid-19, your immune system may have lingering weakness and dysfunction as Yoni Freedhoff, MD, Associate Professor of Family Medicine at the University of Ottawa, alluded to in the following tweet:

The second issue is the overcompensation problem. As the term “revenge travel” embodies, many people may be trying compensate for what they perceive as missed opportunities over the past two years. Revenge travel is the phenomenon of traveling even more extensively this year than in any previous year to supposedly make up for lost time and say a big, “bleep you” to the pandemic when you may actually be saying, “bleep you” to your body and your wallet. The same could apply for revenge dating, revenge partying, revenge raving, revenge meeting, revenge happy houring, and revenge have-sex-with-someone-you-just-met-on-Tindering. It’s difficult to say how much revenging may be going on in 2022 but any such activities could help respiratory viruses get their share of revenge.

The third issue is the laxity problem. Many people may have become even more lax on basic precautions such as getting the flu vaccine, hand hygiene, and staying the bleep out of someone’s face while talking. Part of this could be fatigue. But a big part is poor messaging from federal, state, and local governments and businesses. All of this pandemic-is-over-so-go-ahead-and-vote-for-us-in-the-next-election-and-spend-money-again malarkey may be overshadowing key public health precaution messaging.

The bottom line is that wearing a face mask and maintaining social distancing over the past two years is unlikely to have made you more susceptible to respiratory infections now. There’s no real evidence that this has resulted in a so-called “immunity debt.” Give your immune system more credit than that.