Does COVID vaccination also protect against strokes?


New studies have revealed surprising things

from Dr. Bettina Albers

(01.09.2022) New studies show: There is no increased risk of stroke after vaccination against SARS-CoV-2. Both surveys evaluated very large cohorts and came to the same conclusion. Furthermore, there is initial data that even indicates that vaccination protects against strokes during COVID-19 disease: when infected with SARS-CoV-2, vaccinated people had less than half the risk of suffering a stroke than unvaccinated people .

At the end of March last year, a serious, albeit rare, side effect was observed after COVID-19 vaccination with vector-based vaccines: vaccine-associated sinus and cerebral vein thrombosis occurred, especially in younger women, and there were deaths. This undesirable side effect was not observed when vaccinated with mRNA vaccines, at least not to a frequency that suggested a connection.

As a result, the vector-based vaccine ChAdOx1 (AstraZeneca) was no longer administered to young women. In addition, vaccinated people were sensitized to the main symptom headache after vaccination and doctors were made aware of the phenomenon of the formation of anti-PF4 antibodies. The detection of these antibodies can identify those affected before clinical symptoms of sinus and cerebral vein thrombosis appear, thus allowing early therapy and prevention of this rare complication.

However, a slightly increased risk of hemorrhagic strokes (so-called cerebral hemorrhage) after vaccination with an mRNA vaccine has also been described. An analysis published in “Nature Medicine” in October 2021 showed an increased risk on days 1-7 and days 15-21 after vaccination with BNT162b2 (IRR: 1.27 and 1.38). Since then, all vaccines against SARS-CoV-2 have carried the stigma that they could cause stroke, a concern that understandably leads to anxiety and contributes to vaccine hesitancy. However, two current studies now show that vaccination against SARS-CoV-2 is not associated with an increased risk of stroke.

In a systematic review published in “Neurology”, two randomized studies, three cohort studies and eleven registry-based studies were evaluated. A total of 17,481 cases of ischemic stroke were recorded – with a total of 782,989,363 vaccinations. The overall stroke rate was 4.7 cases per 100,000 vaccinations. Thrombotic thrombocytopenic purpura (TTP) was the underlying cause of only 3.1 percent of strokes resulting from a SARS-CoV-2 vaccination. As the authors conclude, the stroke rate after vaccination is comparable to that in the general population – and the TTP, which led to sinus and cerebral vein thrombosis, a very rare complication, at least according to the precautions that were taken. They also emphasize that the stroke rate in people infected with SARS-CoV-2 is significantly higher.

The second study is a current evaluation of the “French National Health Data System” (Système National des Données de Santé [SNDS]). It was investigated how often cardiovascular events (myocardial infarction, pulmonary embolism or stroke) occurred in people aged 18 to 75 after the first and second administration of vaccines against SARS-CoV-2. A total of 73,325 events were documented in 37 million vaccinated people.

As a result, the study showed that there was no association between mRNA vaccines and the occurrence of these serious cardiovascular complications. The first dose of the vector-based vaccine ChAdOx1 was associated with an increased rate of myocardial infarction and pulmonary embolism at week 2 after vaccination (RI: 1.29 and 1.41), and the Janssen-Cilag vaccine could also be associated with the occurrence of myocardial infarctions at week 2 after vaccination cannot be ruled out. With regard to the stroke rate, however, the evaluation did not show a higher risk for any of the vaccines.

DGN Secretary General Professor Dr. Peter Berlit concludes: “The available data do not show any safety signals with regard to an increased risk of stroke, at least for the mRNA vaccines. The fact that both surveys evaluated very large cohorts and both come to the same conclusion gives us additional security: mRNA vaccines against SARS-CoV-2 do not increase the risk of stroke, so concerns should not prevent people from getting vaccinated to let.”

On the contrary: The expert emphasizes that the SARS-CoV-2 infection is associated with a higher rate of strokes and that the vaccination therefore protects against strokes. This was recently shown by a Korean study: Of 592,719 SARS-CoV-2-positive patients during the study period (July 2020 and December 2021), 231,037 were included in the study. 62,727 were unvaccinated, 168,310 fully vaccinated (two doses of an mRNA or vector vaccine), but they had nevertheless contracted corona. The vaccinated study participants were older and had more comorbidities. Nevertheless, severe or even critical COVID-19 courses were less common in this group, as was the rate of secondary diseases. The adjusted risk for ischemic stroke was 0.40 in the vaccinated subjects, meaning that vaccination more than halved the risk of stroke compared to the unvaccinated group.


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