Flu vaccine causing more flu infections

#1

I’m a strong advocate of vaccination in general, but this study is like the worst nightmare for vaccine advocates.

PREPRINT

Effectiveness of the Influenza Vaccine During the 2024-2025 Respiratory Viral Season

News reports:

This year’s flu shot linked to higher flu risk in adults: Cleveland Clinic study

“To be more specific, the study also found that the vaccine effectiveness was as low as -26.9%, indicating that the vaccine had actually increased the risk of developing influenza. This is a concerning finding, especially considering the fact that the flu vaccine is widely administered every year to prevent the spread of the disease.”

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#2

“but over the course of the study the cumulative incidence of influenza increased more rapidly among the vaccinated than the unvaccinated.”
Wow!

One of the problems with flu vaccines is that they have to make a prediction of which flu viruses they want to target for an upcoming season. They often get it wrong.

Having said that, I have had annual flu vaccinations for over fifty years, and I have never had the flu.

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#3

I don’t know what to believe anymore. However, I don’t get flues and I’m vaccinated. May be it’s a placebo effect. Knock on wood!

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#4

Which explains why I got the flu for the first time in my life this year a few months after getting vaccinated…

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#5

The study is below.

RESULTS

A total of 53402 employees [of Cleveland Clinic] in Ohio remained after excluding 1700 subjects (3.1%) for whom age or gender were missing. These employees formed the study cohort and a total of 43857 (82.1%) were vaccinated by the end of the study. The vaccine was the inactivated 3-valent influenza vaccine in 98.7% of those vaccinated. Altogether, 1079 employees (2.02%) acquired influenza during the 25 weeks of the study. Of these, 1066 (98.8%) were influenza A infections, the remaining being influenza B infections. A total of 2740 subjects (5.13%) were censored during the study period because of termination of employment before the end of the study.

“A total of 2740 subjects (5.13%) were censored during the study period because of termination of employment before the end of the study.”

Did any of the 2740 get sick or not? They were excluded because they were terminated? Still would be relevant to know if they got sick or not.

Nowhere does it say how many of the 1079 were vaccinated, versus not vaccinated. It only states the total.

Baseline characteristics

Table 1 shows the characteristics of subjects included in the study. Notably, this was a relatively young population, with a mean age of 42 years, and 75% were female. About 20% had a clinical nursing job.

Those frontliners had a greater risk. Was there greater illness among them?

Aside from the RNs, the orderlies and caregivers working with them also do bedside duties - feeding, pushing wheelchairs or beds to the OR, etc.

The results are generalizable to relatively healthy adults in the USA, which is a major target of adult influenza vaccination efforts.

What? The study population is comprised of people working in a hospital. Not exactly the majority of the US population.

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#6

Yea, seems like an obvious confounder here is those most likely to get a flu vaccine are people that feel they are most exposed. Even within the given population (employees at a hospital), front liners are very different from back office staff. I suspect the flu vaccine was just ineffective and those with the most risk were more likely to get one, hence it appears that it made things worse.

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#7

Well, it’s important to distinguish between the vaccine itself causing the infection, and the vaccine making you more vulnerable to infection upon exposure to the flu virus.

Anti-vaxxers tend to conflate the two, or indeed claim outright that the vaccine itself infects you. Obviously, since the vaccine works with inactivated virus and virus fragments, we don’t think the vaccine itself is what infects you with the flu, you’d need the active virus for that, and it’s not in the vaccine.

But if, IF, the conclusion of the study us correct, that getting the vaccine makes you more vulnerable to becoming infected upon exposure to the virus, then I am really struggling to understand what the mechanism might be. I think this needs to be looked into ASAP.

Incidentally, I’ve heard forever people telling me (like Antoine here!), that they never had the flu, but got it when they got the vaccine. My MIL is an example, she reported that the one time she got the vaccine, she got the flu, but never all the years without the vaccine - we both laughed ruefully, at the bad luck coincidence (she believes in vaccines), we put it all down to unconnected chance. But now I wonder.

Myself, most of my life I didn’t get the flu vaccine, because I was underwhelmed by the relatively poor effectiveness, so why bother. I wasn’t opposed to the idea, just couldn’t be bothered. But as correlations started coming out about possible protection from dementia, I started getting the flu vaccine. No flu so far. But I’m somewhat concerned, because there also seems to be research indicating that getting infected with respiratory viruses is associated increased dementia.

Hmm. Quite some dilemma. Getting the flu vaccine might cut the odds of my getting dementia. But it may also increase my odds of getting the flu, which in turn might increase my odds of getting dementia. Not a good year, I’d say. Get the vaccine, and then move to a desert island?

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#8

Surely this is the case every year but in previous years the vaccine was effective. So unless there was a sudden change of behavior it means the study is correct.

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#9

The CDC has classified the 2025 flu season as one of “high severity.” Even for the vaccinated, there is always a non-zero chance of contracting the virus. However, those who do get sick following an inoculation are likely to have milder symptoms and much less likely to die. The flu is no joke. About 35,000 die each year in this country alone. And sometimes the virus goes rogue and triggers a pandemic. From 1918-1920, influenza killed about 50 million people, similar to the bubonic plague in the 14th Century. And in a reversal of conventional wisdom, it killed the young and healthy at higher rates than it did the old and feeble.

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#10

I’m not sure we’re on the same page. What I’m suggesting is that if the flu vaccine was not effective this year, more people who got it would contract the flu.

Put another way, assuming that people who are more exposed are more likely to get the flu vaccine, let’s consider two scenarios.

Effective flu vaccine: Flu vaccine recipients show a lower rate of contracting the flu despite higher exposure. People who did not get the flu vaccine show the same rate of contracting the flu.
Ineffective flu vaccine: Flu vaccine recipients show a higher rate of contracting the flu, higher than non-recipients, because they self-selected due to higher exposure. People who did not get the flu vaccine show the same rate of contracting the flu.

Notice that in the second case the reason they have a higher rate of contraction is because the flu vaccine is ineffective AND they were at higher risk (hence why they got a flu vaccine). It’s not necessarily because the flu vaccine made it more likely for them to contract the flu (eg by weakening the immune system or something)

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#11

Ok I get your point now. Yes we should look at the 18% who didn’t get vaccinated: is it just that they had low exposure? Were on leave that year? Etc.

#12

I generally do not get the flu vaccine. One of the reasons is my own risk/benefit analysis that I will be lucky enough to be able to fight off the current virus and gain long lasting immunity that may help me in the future. If I remember correctly, some older people had a certain protection from Swine Flu because of a similar exposure decades before. It’s a gamble either way. For example, I may not get exposed and never build that immunity. I may get exposed and die or develop a post viral syndrome. Or alternatively, I may take the vaccine and get a negative immune reaction, be exposed to harmful additives/adjuvants or take the vaccine and and get absolutely no benefit, as the suggest happened last year. From internet query:

Natural Infection:

Natural influenza infection can induce a robust and long-lasting immune response, including the production of antibodies that can protect against reinfection by the same viral subtype.

Flu Vaccine:

The flu vaccine elicits an antibody response, but it’s not as long-lasting as natural infection.

Protective levels of antibodies decline over time, and it’s generally recommended to get vaccinated each year to maintain protection against the circulating strains.

Annual Vaccination:

The flu virus is constantly changing, and the vaccine is updated each year to match the most prevalent strains. Even if you’ve been vaccinated before, annual vaccination is crucial to maintain protection against new strains.

Why the Difference?

Natural infection allows for a more

comprehensive and robust immune response, including the development of memory B cells that can provide long-term protection. Flu vaccines, while effective, may not stimulate the same level of long-term immunity.

#13

Until you die…

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#14

Great explanation by putting statistics in simple words.
There is a great book titled “Art of Uncertainty” by David Spieglehalter along the same lines.
Here is an illustration from his book that explains the observation why most people who died of COVID were actually vaccinated!

Screenshot_20250322_161433_Libby
Screenshot_20250322_161433_Libby1080×2340 249 KB

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#15

Well, I’m sympathetic to those who are hesitant based on their negative experiences. It’s an undeniable fact that some have been injured by CV-19 vaccines. We should not deny that. And it’s possible that flu vaccines are suboptimal either because, like here, they can actually be a negative vs infection risk, or ineffective because the strain is subtly different for some.

That said, I would not want to get immunity through being infected by the flu virus. First, you have no idea if going through the disease you might not sustain some permanent damage. For example, on my CAC scan, while I had zero score for calcified plaque, there were incidental findings:

“Incidental findings: Calcified nodules and micronodules in the bilateral lungs suggestive of sequela of prior granulomatous infection. Partially visualized linear atelectasis/scarring in the basal right lower lobe.”

OK, I had no idea that I had something like this, because I very, very rarely get sick. I did however go through something - perhaps the flu - which I caught on a plane coming back from London where I celebrated the 2000 New Year. I was pretty sick. That was the last time I can recall getting sick with respiratory involvement. And now I have some kind of permanent lung damage.

Point being, I don’t want that. I’d rather get the vaccine immunity, even if it’s slightly less durable, than get immunity through getting the disease and possibly sustaining some permanent damage. Of course, I’m not judging, perhaps some like damage, so I’m not going to make judgements on their choices.

Furthermore, there is some equivocal evidence, that viruses like the flu can get into the brain and be either causative or contributory factors in the development of neurological damage, maybe even dementia. Not a risk I want to take. Again, not judging, as some may want that effect, to each their own.

Finally, there is the possibility that the flu vaccine might lower the chances of getting dementia. Now, this may be a spurious correlation and it’s pretty speculative, so I’m not putting much stock in this possibility, but if it’s true, hey, as long as I’m getting the shot, I won’t turn down this perk.

Bottom line: there are many reasons for getting the flu vaccine that go beyond whatever temporary immunity is developed against some strain or another. And avoiding the flu altogether is of course best. YMMV.

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#16

I have never had the flu in over forty years of getting annual flu vaccines (unless it was so minor that I never noticed it). I did have a reaction to the swine flu vaccine—a very sore arm.

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#17

“possibly sustaining some permanent damage. Of course, I’m not judging, perhaps some like damage”

“neurological damage, maybe even dementia. Not a risk I want to take. Again, not judging, as some may want that effect”

Actually, you sound quite judgmental and seem to imply that anyone who chooses a different option for their health and has come to a different risk/benefit analysis than you, is hoping for neurological damage, dementia and/or other potential permanent damage. We are all weighing risks and benefits in hopes of the best outcome and rest assured, none of us has a crystal ball to ensure optimal outcome. You have come to your conclusion and can certainly share your reasons without attempting to demean others. I am happy to hear other opinions and adopt new ideas if convinced. However, I highly recommend engaging with humility, respect and common courtesy.

#18

And I recommend paying attention to what’s actually written, it will help in avoiding making incorrect assertions.

"possibly sustaining some permanent damage. Of course, I’m not judging, perhaps some like damage”

“possibly” indicates a hesitancy, not a certainty, and only one of the options. Please consult the dictionary. “perhaps” indicates not a certainty, but only a possibility, only one of the options.

I therefore did not “[…]seem to imply that anyone who chooses a different option for their health and has come to a different risk/benefit analysis than you, is hoping for[…]”. I only indicated that this is one of possible motivations, which poosibility exists, and for some people, not “anyone”: I wrote explicitly “Again, not judging, as some may want that effect, to each their own.” Furthermore, insofar as implications, my plain implication is that even if someone has that particular motivation, I still don’t judge/condemn that choice: “so I’m not going to make judgements on their choices.”.

When arguing against a statement in good faith, you refer to the actual statement, not a made up interpretation which you then assume as the only valid one - that’s building a straw man which you then argue against. No matter how eager you may be to launch an argument against my statements, you still don’t get to make up your own interpretation and claim it as mine - because I am here and in the original text clearly telling you the intent of my statement, which I back up with a plain lexical reference.

“You have come to your conclusion and can certainly share your reasons without attempting to demean others.”

Agreed, and a good thing then that I have demeaned no one, as I don’t indicate that I regard any choice, including the ones I outlined as deserving of judgment or deprecation (in fact I explicitly disavow that), and I think it very troubling that apparently YOU deem some of the choices I outlined as demeaning, because that sounds judgmental towards those who may have made such choices. You see those choices - your word - as “demeaning”, well, I don’t, I think they are perfectly valid. So there.

#19

I will leave you to your lengthy argument and agree to disagree.

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#20

So 82.1% of the medical staff who were mandated at their workplace to get the flu vaccine did, this group had also sought medical attention and had 27% more positive tests of flu than the 17.9% who had medical or religious reasons for not taking the vaccine.

I think it’s more likely that the unvaccinated for medical or religious reasons – at 17.9% had different testing behavior that decreased the amount of positive tests. The study as far as I can see looked at this separately but didn’t adjust for it in their final analysis (where the 27% increase came from), and besides, a lower rate of testing but an equal percent amount of tests positive is a lot of cases you can miss in the final analysis.

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