mRNA Vaccines May Increase Risk of Brain Blood Clots (CVT)
New study shows positive safety signal for mRNA vaccines, although risk appears higher for "viral vector" vaccines like AstraZeneca.
Were we all being “paranoid” for wondering if Hailey Bieber’s brain blood clot might have been vaccine related? Hardly.
Here’s the bottom line from a new study of global vaccine adverse reaction data,
Association of Cerebral Venous Thrombosis with mRNA COVID-19 Vaccines: A Disproportionality Analysis of the World Health Organization Pharmacovigilance Database:
Our study demonstrated a potential safety signal for occurrence of CVT for COVID-19 mRNA vaccination. It is necessary to be aware of the risk of CVT occurrence, even after COVID-19 mRNA vaccination.
First, some definitions of terms:
Cerebral venous thrombosis (CVT) is a blood clot in the brain, specifically in the cerebral vein that drains blood from the brain.
VigiBase is the World Health Organization’s global adverse reactions database.
BNT162b2 = Pfizer/BioNTech mRNA vaccine.
mRNA-1273 = Moderna mRNA vaccine.
ChAdOx1 nCoV-19 = AstraZeneca vaccine, aka Vaxzevria, a non-mRNA viral vector vaccine that works similarly to the Johnson & Johnson vaccine that was recently restricted by the FDA due to blood clot risks.
While the mechanisms for mRNA and viral vector vaccines are completely different, both types of vaccines incite your body’s cells to produce spike proteins.
The new study is an assessment of WHO’s VigiBase data. A strong “positive safety signal” was discovered in relation to cerebral venous thrombosis (CVT) and both mRNA and viral vector vaccines.
The viral vector vaccines (AstraZeneca, etc.) appear to have a higher risk of CVT, but mRNA vaccines may also carry an elevated risk of cerebral venous thrombosis.
Of course, the study authors had to kowtow to the vaccine religion prior to sharing their findings with this statement:
Coronavirus disease 2019 (COVID-19) is spreading rapidly [1,2,3,4,5]. Herd immunity is important for the prevention and suppression of the spread of COVID-19, and vaccination is an essential requirement for herd immunity .
Minor rant: How on earth is vaccination an “essential requirement for herd immunity” when the “vaccines” in question don’t stop people from catching and spreading the disease? So we’re to believe that herd immunity isn’t possible with natural immunity? How on earth did human beings survive for the millennia before the magical vaccines?
At any rate, from the study (emphasis mine):
Cerebral venous thrombosis (CVT) is defined as the presence of a blood clot in the cerebral veins or dural venous sinuses. CVT is accompanied by headaches, stroke-related symptoms, and seizures . Hematologic disorders, inflammatory diseases, pregnancy, malignancy, hormonal abnormality, and meningitis are the main associative or risk factors for the development of CVT . The risk factors of CVT after COVID-19 vaccination were similar, with the exception that allergic reactions to the vaccine components and platelet abnormalities were additional factors . Since the initiation of COVID-19 vaccination, cases of CVT associated with COVID-19 vaccines have been reported, with some being fatal [16,17,18,19,20]. Because CVT is a rare disease, case reports or case series of CVT after COVID-19 vaccination are very rare. Moreover, because these reports mainly focus on unusual or interesting cases, it is necessary to investigate the effect of COVID-19 vaccination on real-world CVT occurrence. In addition, although case reports and series have been reported on the association between the ChAdOx1 nCoV-19 vaccine and CVT [16,17,18,19,20], there have been few studies on the associations between mRNA COVID-19 vaccines and CVT.
Did I just read that correctly, that the “risk factors” of getting CVT thanks to vaccines are “similar” to general risk factors, which include pregnancy? And how much actual study has been done regarding the impact of these vaccine technologies on pregnancy? Or how the vaccines might affect people on birth control or hormone replacement therapy (HRT)?
Hey, I have a bright idea…let’s also put kids on puberty blockers and cross-sex hormones and then jab them with an experimental vaccine. Surely this will be totally safe! (That was sarcasm, in case you missed it.)
The study found that both mRNA and viral vector vaccines may increase risk of CRT, but the timing is different, per the graph below:
The characteristics of the subjects were summarized by descriptive statistics; proportions were used for categorical variables and medians with interquartile ranges for non-normally distributed continuous variables, such as time to onset. Categorical variables were compared using the chi-square test or Fisher’s exact test. Differences in time to onset among vaccines were analyzed using the Kruskal–Wallis test with a Bonferroni’s post hoc analysis for intergroup comparison. Two-sided p ≤ 0.05 were considered statistically significant. Statistical analyses were performed using R software, version 3.3.3 (R Foundation for Statistical Computing, Vienna, Austria), and SAS 9.4 (SAS Inc., Cary, NC, USA).
From my naked eye it looks like Pfizer (BNT162b2) has the highest risk in the first week, while AstraZeneca (ChAdOx1 nCoV-19) seems a bit more tilted towards week 2.
These cases of cerebral venous thrombosis are not mild. According to the study, “33% did not recover or died” (how do you “not recover” but not die? coma?) and more than 9 in 10 ended up in “serious condition.”
More than 90% of the patients were in serious condition, and 33% did not recover or died. The outcome of death after CVT was significantly higher in patients who received the ChAdOx1 nCoV-19 vaccine than in those who received the mRNA-based COVID-19 vaccines (odds ratio (OR) = 0.32; 95% CI, 0.22–0.45; p < 0.001). In pairwise comparisons of the different types of vaccines, vaccination with ChAdOx1 nCoV-19 more often led to death after CVT than vaccination with BNT162b2 (OR = 0.35; 95% CI, 0.25–0.50; p < 0.001) or mRNA-1273 (OR = 0.18; 95% CI, 0.07–0.44; p < 0.001) (Supplementary Table S1).
The risk of CVT is apparently higher for AstraZeneca, along with the risk of death, roughly twice as high, if I am reading those numbers halfway correctly (I am not a statistician). However, it is important to note that elevated CVT risk was also found with mRNA vaccines (emphasis mine):
A significant signal of disproportionality of CVT was noted for all COVID-19 vaccines (IC025 = 2.01; ROR025 = 5.14) and separately for the mRNA-based COVID-19 vaccines (IC025 = 1.56; ROR025 = 3.27) and the ChAdOx1 nCoV-19 vaccine (IC025 = 2.56; ROR025 = 6.70) with respect to IC025 and ROR (Figure 2).
Here are the limitations of the study (emphasis mine):
Our study has limitations. First, if the national drug-monitoring center of a country does not report ADRs, these cases will not be present in VigiBase. However, VigiBase includes rare ADRs and generalized ADR information from more than 130 countries. Second, VigiBase does not provide any validation of laboratory findings, radiologic information, or accuracy of diagnosis. Information on whether CVT occurred after the first or the second vaccine dose was also not included. Third, vaccine-induced immune thrombotic thrombocytopenia received major public attention after April 2021 , and this may have affected the increased reports of CVT cases after COVID-19 vaccination. Lastly, as mentioned above, it is difficult to directly compare outcome parameters, including death, between the different types of COVID-19 vaccines in VigiBase.
Well, I don’t know about you, but I think finding out whether these CVT events are more likely to happen after a second (or third or fourth) vaccine dose would be kind of important.
Meanwhile, Vaxzevria (AstraZeneca) has just been approved by the European Medicine Agency (EMA) as a “third-dose booster” shot for COVID-19.
Now Pfizer wants to shoot up kids under 5 with the claim that three “smaller doses” of their mRNA vaccine is 80% effective at “protecting them” from the virus:
Pfizer and BioNTech had initially planned a two-dose regimen for children younger than 5, but added the third dose when just two failed to offer the expected level of protection against the coronavirus.
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