If we push the pro-vax narrative with bad science, it’s no different than what the anti-vax narrative does.
A new study published in Nature Cardiovascular Research, found an increased risk of postural orthostatic tachycardia syndrome (POTS) from both Covid-19 and its vaccines — and that such risk is 5-times higher from Covid-19 than its vaccines — has taken the media by storm.
The pro-vaccine side likes the study as it shows that the risk of POTS is 5-times higher from infection than vaccination. The anti-vaccine side also favors the study because it suggests vaccines can cause POTS.
But after looking at the data more closely, the study’s own interpretations are flawed, as other experts have also noticed. The risk of POTS from Covid-19 versus its vaccines may be equal or, at most 2-times, higher instead, not 5-times. This study even found additional risks of both Covid-19 and its vaccines, such as low back pain, anemia, and urinary tract infection, but these are likely just statistical noise.
Let’s see why and what this study actually means for vaccine safety.
Before we begin, let’s briefly define POTS. It’s a chronic disorder of the autonomic nervous system, where the person experiences dizziness and rapid heart rate upon standing up. This is because the body can’t maintain sufficient blood pressure, and the heart can’t pump blood to the brain in time. And POTS is a known complication of long-Covid.
What the study did and found (feel free to skip this)
Scientists from Cedars-Sinai, a nonprofit academic medical center in the U.S., conducted the study, which recruited 284,592 vaccinated and 12,460 infected individuals from 2020 to 2022. Those who were infected and later vaccinated, and vice-versa, were excluded from the study.
The study used a self-control design, where individuals act as their own controls. Specifically, the unvaccinated and vaccinated groups are derived from the same people during the 90-day pre- and 90-day post-vaccination periods. Likewise, the uninfected and infected groups are the same people during the 90-day pre- and 90-day post-infection periods.
The main study results were that the risk of new diagnoses of POTS after vs. before vaccination increased by 1.52-times. And such risks were not affected by age, sex, ethnicity, number of doses, and vaccine type (Pfizer mRNA, Moderna mRNA, and J&J DNA).
For new diagnoses post-infection, the risk of POTS was up by 2.11-times. Such POTS-associated risks were not affected by sex and ethnicity, but may be affected by old age (mean age of 60 vs. 47 in post-infection POTS vs. pre-infection group).
Lastly, the study computed the risk of POTS-associated diagnoses between post-infection and post-vaccination, finding a 5.35-times increased risk from infection versus vaccination (Figure 1).
This is calculated by adding all diagnoses from the POTS diagnostic group, which includes POTS, fatigue, dysautonomia, Ehlers–Danlos syndrome, and mast cell disorders from each of the vaccinated and infected groups. As a result, there were 2,581 POTS-associated diagnoses in the vaccinated group (out of 284,592, which gives 0.91%) and 605 POTS-associated diagnoses in the infected group (out of 12,460, which gives 4.86%), a 5.35-times increase.
The risk of POTS from vaccine and infection seems similar, but comparing both groups is illogical.
Continuing from the last point that the risk of POTS-associated diagnoses is 5.35-times higher from infection versus vaccination, it’s illogical to compare the two groups of individuals. Let’s see why.
Mobeen Syed, MD, MS, a physician, software engineer, medical educator, and Youtuber, pointed out that the baseline pre-exposure rate of POTS was already 4.7-times between the vaccinated and infected groups (Figure 2).
Specifically, there were 1,945 POTS-associated diagnoses in the vaccinated group before they got vaccinated, which is 0.68% out of 284,592 people. And there were 399 POTS-associated diagnoses in the infected group before they got infected, which is 3.2% out of 12,460. Dividing 3.2% by 0.68% thus gives 4.7-times difference at baseline before the exposure.
Therefore, the actual difference in POTS risk in the infected versus vaccinated group may only be 5.35-times divided by 4.7-times, giving 1.14-times, which is most likely statistically insignificant. This could mean that POTS-associated risks are equal between vaccination and infection.
Even if you count only POTS diagnoses (and not the other POTS-associated diagnoses), such diagnoses before exposure were 501 out of 284,592 (0.176%) pre-vaccinated individuals and 123 out of 12,460 (0.987%) pre-infected individuals. This difference is 5.6-times. In other words, the baseline difference in POTS between the vaccinated and infected groups (before they got vaccinated/infected) is already 5.6-times.
“But that 5-times difference was already present even before the exposure to the event [vaccination/infection] had occurred. So these cohorts were already 5.5-times different without any event,” Dr. Syed said. “Did they explain or discuss or address that there was already a difference of 5-times before?” And no, the study paper did not.
That said, we can speculate a few reasons why there was such a huge 5-times baseline difference in POTS:
- The average age of the infected group was slightly higher than the vaccinated group (56 vs. 52).
- The infected group also had a higher incidence of common medical comorbidities before infection than the vaccinated group before vaccination, such as hypertension (1,734 vs. 731 per 100,000 people), diabetes (690 vs. 211 per 100,000 people), urinary tract infection (1,340 vs. 309 per 100,000 people), fatigue (2,207 vs. 484 per 100,000 people), and headache (1,998 vs. 385 per 100,000 people).
Therefore, the infected population appears older and less healthy before infection than the vaccinated population before vaccination. The healthy vaccinee effect is likely involved — and rightly so because it’s a common confounder across vaccine observational studies — where ill individuals are more likely to delay or avoid vaccination until they recover.
“If I come to you and say I have two groups. And they both have, before any intervention (infection or vaccine), a 10-times difference in their incidence rate,” Dr. Syed continued. “Then I come back afterward and say, they still have the 10-times difference after the vaccine and infection. But I only want to tell you that after the vaccine and infection, the difference between them to each other is 10-times. Would that be very accurate to do?”
We can still compare the two groups but skeptically
The Gift Of Fire has also written on this topic (title: New study measures the frequency of covid vaccine injuries), which offers a lot of insight. Therein, the writer argued that the risk of POTS from Covid-19 may actually be 2-times higher than from its vaccines.
Looking back at Tables 1 and 2 (as well as Figure 2), there were 501 and 763 new diagnoses of POTS before and after vaccination, an excess of 262. And 262 out of 284,592 vaccinated sample size gives 0.092%. Likewise, there were 123 and 260 new diagnoses of POTS before and after infection, an excess of 137. And 137 out of 12,460 infected sample size gives 1.1%.
So, the rate of new POTS diagnoses after the exposure is 12-times (1.1% divided by 0.092%) higher in the infected compared to vaccinated group. And if there was already a 5.6-times baseline difference in POTS diagnoses between the two groups, that means the rate of POTS from infection versus vaccination may actually be just 2.1-times (12 divided by 5.6).
That said, Dr. Syed offers another way to look at the data — by comparing the odds ratios between the two groups. As Dr. Syed said, “The post exposure comparison of the absolute numbers is not correct. Only the odds ratio can be taken as the cohorts are unequal, and the incidence of POTS in the infection cohort is way higher. But they did it anyway. And got away with it. They should not even have put this study together.”
- Looking at POTS diagnoses only, the odds ratios were 2.11 after infection and 1.52 after vaccination, as the study authors calculated. Dividing them (2.11 by 1.52) means that the odd ratio of POTS diagnoses from infection versus vaccination is just 1.39-times.
- Likewise, if you look at POTS-associated diagnoses altogether, its odds ratio is 1.3 in the vaccinated group and 1.5 in the infected group; dividing them gives only 1.15-times, which is most likely statistically insignificant, according to Dr. Syed. (Figure 2).
So, if we must compare both groups, the risk of POTS and its associated diagnoses is at most 2-times higher from infection than vaccination. But the risk of POTS alone is equal from both infection and vaccination.
But given that the infected group was older and had more comorbidities than the vaccinated group, we don’t know if we should attribute the increased POTS-associated diagnoses to the infection, age, and/or comorbidities. And the study, unfortunately, does not control for these variables, which makes a comparison between the two groups unwise.
Yet the study claims that POTS risk is 5-times higher from infection and vaccination anyway, perhaps partly to push the narrative that the virus is more dangerous than the vaccine.
While I side with this narrative, because I believe it’s mostly but not fully true based on all the articles I’ve written on vaccine safety, it’s double standards to support this narrative with bad or flawed science, else it’s no different from what the anti-vaccine community does.
Even an editorial of the study by another group of scientists from the U.S. overlooked this flaw, even estimating that the risk of POTS from infection is up to 6.8-times higher than vaccination. But as The Gift Of Fire pointed out, “they don’t consider that the vaccinated group and the infected group aren’t comparable — one group may be healthier than the other.”
What it means for vaccine safety
In the end, the new POTS study, published in a highly reputable journal, has some good and novel data, but such data was analyzed and interpreted wrongly, either by genuine mistake, pro-vaccine biases, or propaganda.
Good science has to be objective, even if it challenges the views and principles we swore by. In this case, the Covid vaccine safety profile took a hit from the POTS study data. We have now discovered a new risk of Covid vaccines (and Covid) that we were unaware of.
But that said, the risk of POTS from the vaccine is still minimal. In the study, there was only an excess of 262 new diagnoses of POTS out of 284,592 individuals after vs. before vaccination. This gives an absolute excess of 0.092% of the vaccinated population, which is not negligible.
Now, what does this study means for vaccine safety? It’s hard to say, honestly, since this study has many unanswered questions.
For instance, the study excluded those who were infected after vaccinated, or vice-versa. Since vaccines don’t fully prevent infection, it’s hard to gauge what’s the risk of POTS from both the vaccine and virus. The study also did not separate their analyses by Covid severity — i.e., is there any difference in POTS risk between mild and severe Covid? If there is, vaccines may still offer benefit in reducing the risk of POTS from severe Covid.
More research is definitely needed to better understand the risk-benefit profile of Covid vaccines now, in terms of POTS and other factors. The only upperhand Covid vaccines have over Covid now is the fact that vaccines prevent severe Covid and its aftermath, such as long-Covid.
Lastly, an open, objective, and unbiased discussion on vaccine safety is worth the effort, so people who actually got harmed by the vaccine can get help and compensation, rather than pushed aside in the name of pro-vaccine. As The Gift Of Fire puts it well, “If we want people to not be vaccine-hesitant, we need to be honest about the risks, and also open to helping them when something does go wrong.”
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