Please don’t contribute to what is already a veritable swamp of disinformation, Dr. Jetelina.

“Immunity debt” isn’t a thing, because we know that immune systems don’t get stronger with repeat exposure to viruses. Additionally, this idea doesn’t hold up under even the most piddling questions from a non-scientist like me, such as:

1) If this were true, why are states that never had masking/distancing/“school lockdowns” (like in the Southern states) still suffering major waves of illness? Shouldn’t they have been spared these so-called “catch-up” waves, since they have been letting viruses tear through populations this whole time? I live in Georgia, where masking was NEVER a thing— even in medical settings— and schools never had masking requirements and only closed for about 8 weeks in April-May 2020. And I know that many other states— Alabama, Mississippi, Florida, South Carolina, Texas, Arizona, Oklahoma, Kentucky all come to mind— were the same way. So, if one were to buy into the “immunity debt” idea, why are those states still seeing record illness levels?

2) Why are places like Sweden, which famously boasted about its refusal to lockdown, still recording high excess deaths?

3) Why are places like India— which occasionally tries to do the mask mandate thing but hasn’t been very consistent across its enormous population — still getting slammed with waves of COVID and other weird opportunistic infections?

4) We know that the astronauts lucky enough to go to space have to quarantine before a space trip (no hospitals up there) and those going to the ISS stay up there— in a disease-free environment— for months. We know that their bodies are subjected to extensive study and analysis upon their return— which is how we know about the effects of gravity on muscle and bone, for example— and not once in the last 50 years has anyone found an astronaut with “immunity debt” from lack of viral exposure. We also know that immune-naive babies are born every hour of every day of every year all over the world, and we don’t see crushing waves of illness as those little immune systems run up against pre-2020 viruses.

5) Why is this “immunity debt” phenomenon totally new in medical literature and never seen before 2021, and only to justify a “return to normal”? In fact, before 2021, public health officials’ position was that AVOIDING illness was the better way to go, instead of loudly courting repeat illness as they are now, in service to this “immunity debt” deity that they invented out of thin air.

Also, Dr. J, if your position is that the evidence is “thin” on COVID-induced immune dysregulation, then you’re not looking too hard. There are dozens of studies highlighting the effects on CD4, CD8, and T cells at this point.

Lymphopenia/lymphocytopenia, a lack of white blood cells to fight infection, is caused by several things— but even according to official statements from NIH and pharmaceutical company Merck, one of the main causes of that condition is a COVID infection.

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I think there is a combination of factors at play, including temporary immunity debt from quarantine/previous infection prevention measures… but I think the additional argument that immune system dysregulation is occurring much more broadly than we would like to admit, needs to be considered. Here is a somewhat alarming counterpoint, but worth a read and discussion:


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What about the data that shows that over 70% of household Covid spread started with a child? How does having ZERO protections on schools help the children stay healthy? What are the consequences of repeat infections and constant absenteeism? Many school boards won't allow student to stay home for the appropriate amount of time to not spread disease to everyone around them? Mask mandates and proper filtration/ventilation are illegal in Florida. We can't protect ourselves or the kids. I have always avoided school age children (and their parents) this time of year because school aged kids have always been viral incubators of plague and that's only gotten worse.

Isn't brain damage a big issues especially with Covid infection in children?

All this messaging is so weak. What happened?

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“In the first 2-3 years of the pandemic, RSV and flu, for example, were incredibly suppressed due to pandemic control measures.”

We didn’t have mandated control measures in place for that long, and implementation was not consistent throughout the U.S.. I’ve seen this statement elsewhere many times, and it just isn’t supported. Just think about it.

Immune dysfunction due to previous COVID infection(s) needs to be looked at more closely, especially in children, who will be dealing with the repercussions for decades.

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So am I the crazy one since I still mask and avoid crowded I door spaces? We hear about vascular damage, heart attacks, strokes, etc. Is that from people looking to rile up people like me who are still overly cautious? It’s a sincere question because everyone else has moved on.

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I must agree with the authors that are doubting immunity debt. There are a lot of articles that point to covid affecting much of the immune system. Cardiovascular-wise there is good evidence that there is an acute and a subacute phase that is immune modulated and can continue for many months for some people and place them at higher risk for myocardial infarction, aneurysm and stroke… even with mild- moderate symptoms. I suspect in children this can present more clinically with elevated levels of autoimmunity (MISC, diabetes, Crohn’s, celiac etc) and immune dysfunction seen with repeated illness and inability to fight off infection. By now some would have had 2-3 covid infections/ year without any mitigation efforts. In my practice we have found people who are positive for elevated inflammatory cytokines for many months and others who have elevated d-dimer and fibrinogen levels over 1 year post covid infection. I have had hospitalized patients who have had necrotizing pneumonia (supposedly rare)- thought to have occurred because the beta amyloid clots from covid which are typically thicker than normal cardiovascular clots block smaller areas of the arteries that did not allow antibiotics to get to the areas needed to alleviate infection. Additionally, there is the mounting amount of research in immunology that says covid causes so much dysfunction to so many cells for many months with the average recovery time being around 6-8 months or longer. I agree with the other authors that covid infection is multifactorial with an overall effect to decrease resilience to fight off infection. If children are being repeatedly infected, then I can imagine that they will essentially be in a chronic immunocompromised state. In the US only 51% of schools used covid ESSER funds to improve air quality. My kids are sitting in classrooms where CO2 levels are consistently greater than 1600 ppm. This is twice what is recommended by CDC to decrease respiratory viral infections. Because covid had such a low mortality rate for children many schools thought they could put the money elsewhere (new pool, new admin building etc.) Covid is the flu right?... and no one would notice. Sept 2024 is the last month to use COVID ESSER funds. Our school district was given 36.5 million. The school district refuses to tell us what HVACs they have changed and what air improvements they have done. Last year we were 40.3% chronically absent. We will see what this year brings. Our area has had no real mitigation efforts for the last 2.5 years. Something else is happening.

If 10 percent of the population (or more) have long covid, then I suspect that at minimum that group would be at risk for chronic immune dysfunction with repeated infection and no mitigation effort. I suspect clinically this number is more but those infected then recover, and with some mitigation, they don’t get reinfected again so frequently.

Here are a few research sites and articles related to immune dysfunction and covid… there is so much more not listed.



https://www.frontiersin.org/articles/10.3389/fmed.2023.1011936/full A review of cytokine-based pathophysiology of Long COVID symptoms

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9967513/#:~:text=Currently%2C%20it%20is%20hypothesized%20that,Multiple%20tissue%20damage%20and% Persistent SARS-CoV-2 Infection, EBV, HHV-6 and Other Factors May Contribute to Inflammation and Autoimmunity in Long COVID

Post-acute sequelae of COVID-19 is characterized by diminished peripheral CD8+β7 integrin+ T cells and anti-SARS-CoV-2 IgA response



Front Immunol. 2022; 13: 843342.

Published online 2022 Feb 21. doi: 10.3389/fimmu.2022.843342

Depletion and Dysfunction of Dendritic Cells: Understanding SARS-CoV-2 Infection


Published: 14 January 2022 Long-term perturbation of the peripheral immune system months after SARS-CoV-2 infection


https://www.nytimes.com/2020/06/26/health/coronavirus-immune-system.html How the coronavirus short circuits the immune system


We analyzed 71 COVID-19 patients compared to recovered and healthy subjects using high dimensional cytometry. Integrated analysis of ∼200 immune and >30 clinical features revealed activation of T cell and B cell subsets, but only in some patients. A subgroup of patients had T cell activation characteristic of acute viral infection and plasmablast responses could reach >30% of circulating B cells. However, another subgroup had lymphocyte activation comparable to uninfected subjects. Stable versus dynamic immunological signatures were identified and linked to trajectories of disease severity change. These analyses identified three “immunotypes” associated with poor clinical trajectories versus improving health. These immunotypes may have implications for therapeutics and vaccines.


Decreased T cell populations contribute to the increased severity of COVID-19.

Clin Chim Acta. 2020 Sep; 508:110-114.


Immunologic perturbations in severe COVID-19/SARS-CoV-2 infection


A consensus Covid-19 immune signature combines immuno-protection with discrete sepsis-like traits associated with poor prognosis


Reduction and Functional Exhaustion of T Cells in Patients With Coronavirus Disease 2019 (COVID-19)

Bo Diao et al Front Immunol. 2020


Long-term perturbation of the peripheral immune system months after SARS-CoV-2 infection

Whole blood RNA sequencing reveals significant perturbations to gene expression in COVID-19 convalescents until at least 6 months post-infection


Profound dysregulation of T cell homeostasis and function in patients with severe COVID-19



Dendritic cell deficiencies persist seven months after SARS-CoV-2 infection

https://www.frontiersin.org/articles/10.3389/fmed.2023.1011936/full A review of cytokine-based pathophysiology of Long COVID symptoms


Persistent clotting protein pathology in Long COVID/Post-Acute Sequelae of COVID-19 (PASC) is accompanied by increased levels of antiplasmin

https://www.science.org/doi/abs/10.1126/scitranslmed.abq1533 Core mitochondrial genes are down-regulated during SARS-CoV-2 infection of rodent and human hosts 9 Aug 2023


Core mitochondrial genes are down-regulated during SARS-CoV-2 infection of rodent and human hosts

https://www.nih.gov/news-events/nih-research-matters/sars-cov-2-can-cause-lasting-damage-cells-energy-production August 22, 2023 SARS-CoV-2 can cause lasting damage to cells’ energy production


Mitochondrial metabolic manipulation by SARS-CoV-2 in peripheral blood mononuclear cells of patients with COVID-19


Altered bioenergetics and mitochondrial dysfunction of monocytes in patients with COVID-19 pneumonia


Int J Mol Sci. 2023 May; 24(9): 8034.

Published online 2023 Apr 28. doi: 10.3390/ijms24098034 Possible Pathogenesis and Prevention of Long COVID: SARS-CoV-2-Induced Mitochondrial Disorder



A prospective cohort of patients with COVID-19 infection between 16 March 2020 and 30 November 2020 was identified from UK Biobank, and followed for up to 18 months, until 31 August 2021.

https://academic.oup.com/cardiovascres/advance-article/doi/10.1093/cvr/cvac195/6987834 COVID-19 infection, including long-COVID, is associated with increased short- and long-term risks of CVD and mortality.

https://pubmed.ncbi.nlm.nih.gov/33510633/ Impact of COVID-19 on Mitochondrial-Based Immunity in Aging and Age-Related Diseases


Serotonin reduction in post-acute sequelae of viral infection

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I have appreciated Dr J's newsletter and calm, reasoned approach throughout the pandemic, but this one is a real disappointment. The idea that there were extensive lockdowns and masking throughout the country or world is simply not accurate. The (many) states that actively prohibited anti-covid measures are still experiencing record illness. Same with countries who didn't lock down. Why is no one able to respond to this?

Having had RSV or the flu one season doesn't stop you from getting it the next, so in what way does NOT getting it one season make you MORE susceptible the next?

With anywhere from 15-70% of the population experiencing long covid, a syndrome which most studies and doctors seem to agree is related to inflammatory processes, do we now think systemic inflammation DOESN'T make one more susceptible to illness? Why would it NOT be related to how frequently people seem to be getting sick, and how much sicker they seem to be getting?

T cells and B cells are not the only elements of a functioning immune system, not by a long shot, and saying no one has reproduced one paper's suggestion that covid harms B cells isn't even a great argument that it doesn't harm them. How does this make the case for covid harming the immune system "weak"?

This post feels like a lot of wishful thinking. It feels like being asked to disregard what we're seeing in front of our faces: friends and family sick all the time, over and over, with lots of weird things and not just flu or RSV.

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My scientific expertise is in other areas, but I will observe that I’ve read comments from a number of scientists who have worked on HIV for years to decades and who are thoroughly convinced on the question whether COVID infection does indeed cause a progressive dysregulation of the immune system.

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This has been the first Fall season since the pandemic began that I have heard so many coughing young children out in public. They are everywhere I go. Very productive coughs. What I can't understand is why the parents are bringing these children out in public, stores and even restaurants.

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Nov 30, 2023Liked by Katelyn Jetelina

As always, thank you for keeping us informed. I have other COVID-related questions and wonder if you have any related evidence to share with us:

- are we making any progress on understanding long-covid?

- do we know anything about the long term effects of getting covid? I remember reading somewhere that there was a correlation between kids who had gotten COVID and kids who suddenly developed type-1 diabetes or other auto-immune diseases. Have we reached any sort of conclusions? Thank you!

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Nov 30, 2023·edited Nov 30, 2023

A related (naive?) question; has there been any data on "imunity debt" in the ever shrinking group of people that are continuing agressive precautions against Covid-19? Are people that have been vaccinated at every opportunity, are masking and have not been infected with, well, anything in 3 years putting themselves at risk from lack of exposure?

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Could our immune system be producing useless non-neutralizing antibodies because of over-vaccination with mRNA vaccines, or could the selection of the spike protein as the target have been a huge blunder?

One study, published in the journal Nature Medicine, found that over-vaccination with mRNA vaccines in mice led to the production of non-neutralizing antibodies that could actually enhance infection with the virus.

Another study, published in the journal Cell Reports, found that over-vaccination with mRNA vaccines in humans led to the production of a type of antibody called an Fcγ2R inhibitory antibody. These antibodies can interfere with the immune system's ability to clear infections.

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I think the evidence for "immunity debt" is weak at best. Influenza last year was at typical levels. Early in the season, but otherwise typical. Childhood vaccination is down which is certainly a problem. All of the respiratory diseases undergo cyclic variation, which may or may not have anything to do with COVID or precautions against COVID taken during the pandemic. COVID may have nothing to do with any of this. None of the hot linked literature in your post is convincing.

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Nov 30, 2023·edited Nov 30, 2023

Please do not conflate the debunked 'immunity debt' with what Dr J has previously called 'catch-up.' They are 2 entirely different notions. Instead of looking for examples of the term being used to mean catch-up, look at the examples of the term being used to mean 'let it rip,' and see the potential for harm in using the term at all.

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Dec 1, 2023·edited Dec 2, 2023

Immunity debt makes no sense to me - I don't understand how the pool of susceptibles increases when infection by the viruses concerned do not induce lasting immunity. Otherwise we would not need yearly flu vaccines, for example. Could you clarify this for me?

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Can part of the increase be attributed to relaxation of public health measures (decreased masking, decreased participation in vaccinations) which would allow increased spread, not just of CoVid, but also of RSV & flu?

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