64.9 million people in Germany have received at least one corona vaccination. Some of them, although only a few, report vaccination side effects or complications. What exactly are these and how do scientists assess the situation worldwide?
For a large-scale study, an international team of researchers evaluated the data from 99,068,901 vaccinated people from ten locations, specifically from Denmark, Finland, France, Scotland, Argentina, Australia (New South Wales and Victoria), Canada (British Columbia and Ontario) and New Zealand. These countries or regions are part of the multinational Global Vaccine Data Network (GVDN), which is funded by the US CDC.
The scientists focused on the three most frequently administered vaccines
Comirnaty (BNT162b2) from Biontech/Pfizer, Spikevax (mRNA-1273) from Moderna and Vaxzevria (ChAdOx1) from Oxford/Astrazeneca.
13 predefined possible complications resulting from corona vaccinations were examined
The researchers checked whether certain “adverse events of special interest” (AESI) occurred in a risk interval of zero to 42 days after a corona vaccination. These were formulated in 2020 by the “Safety Platform for Emergency vaccines” initiative to assess the safety of the vaccines. Specifically, the following 13 AESI were examined:
Neurological complaints
Guillain-Barré syndrome (muscle weakness) transverse myelitis (inflammation of the spinal cord) facial paralysis acute disseminated encephalomyelitis (inflammation of the brain) seizures febrile convulsions
Hematological complaints
cerebral venous sinus thrombosis splanchnic venous thrombosis pulmonary embolism thrombosis in unusual locations thrombocytopenia (low platelet levels) and immune thrombocytopenia (formation of antibodies against blood platelets)
Cardiovascular problems
Myocarditis (inflammation of the heart muscle) Pericarditis (inflammation of the pericardium)
The evaluation was based on the principle of “Observed versus Expected” analysis (OE ratio), i.e. the comparison of the expected incidence of a disease in the target population (without vaccination) and the actually reported incidence (with vaccination) in a certain time window. If the value was above 1.5, the researchers classified it as a “statistically significant safety signal”.
In the study, those affected were those who had been recently vaccinated and who had been treated as an inpatient in a clinic or as an inpatient or outpatient in an emergency room within 42 days. In countries where such a patient type was not clearly defined, hospital contacts were used as a proxy.
The researchers found a “safety signal” in these vaccination side effects
The researchers registered a “statistically significant safety signal” (OE ratio in brackets) for:
Neurological complaints:
In the case of neurological diseases, an increased OE ratio was found, particularly after an Astrazeneca vaccination. Accordingly, significantly more cases of Guillain-Barré syndrome (2.49), acute disseminated encephalomyelitis (2.23) and transverse myelitis (1.91) occurred.
To illustrate: 76 cases of Guillain-Barré syndrome were expected, but 190 were observed (= OE ratio of 2.49). The occurrence is still rare, but the connection has been recognized by the World Health Organization (WHO) and the European Medicines Agency (EMA) and included in the specialist information as a rare side effect.
However, even after one dose of the Moderna vaccine, significantly more cases of acute disseminated encephalomyelitis/encephalitis (3.78) and transverse myelitis (1.50) were detected.
For the other neurological events, the threshold for a prioritized safety signal was not reached after vaccination.
Hematological complaints :
Among the hematological diseases, cerebral venous sinus thrombosis was found to be particularly common. It occurred most frequently after a vaccination with Astrazeneca (3.23). A total of 21 events were expected and 69 events were observed. Corresponding observations ultimately led to age-dependent restrictions being introduced in Germany; the AstraZeneca vaccine has no longer been available in this country since December 2021.
However, the OE ratios for cerebral venous sinus thrombosis are also increased with the vaccinations with Biontech/Pfizer (1.49) and Moderna (1.48), but they are just below the defined 1.5 limit.
After a third dose of the AstraZeneca vaccine, an increased OE ratio for thrombocytopenia (1.95) and pulmonary embolism (1.88) was also observed.
For the other hematological events, the threshold for a prioritized safety signal was not reached after vaccination.
Cardiovascular complaints after a corona vaccination:
More cases of myocarditis, i.e. inflammation of the heart muscle, have been reported, particularly with the mRNA vaccines (Biontech/Pfizer and Moderna). Here the OE ratio after the first, second, third and fourth doses was above the threshold for a priority safety signal of 1.5. The relevant specialist information has already been updated accordingly. The highest values were observed after the first and second doses of Moderna (3.48 and 6.10, respectively).
In the case of pericarditis, i.e. inflammation of the pericardium, a priority safety signal was also found after a Moderna (1.74, second dose 1.67) and Biontech/Pfizer vaccination (1.54). Astrazeneca did significantly better here. The only exception is the third dose. While the OE ratio after the first Astrazeneca dose is still 1.29, after the third dose it is 6.91.
For the other cardiovascular events, the threshold for a prioritized safety signal was not reached after vaccination.
How should you classify the study on side effects of the corona vaccination?
The study contains a huge database and confirms the known safety signals listed in the respective specialist information. However, the scientists emphasize that
the threshold of 1.5 is relatively high. “It was chosen based on expert opinion within the GVDN and the CDC to focus on the results that are most likely to be considered true signals,” they write. “While some observed events do not meet this threshold, they may still be clinically important and warrant further investigation.”
The safety signals identified in this study from vaccination are compared to the risk from a corona infection must . “In a general risk-benefit assessment of the vaccination, the risk of these diseases associated with a corona infection should also be taken into account,” they write. Several studies have shown a higher risk of, for example, Guillain-Barré syndrome, myocarditis or acute disseminated encephalomyelitis after a Sars-CoV-2 infection than after a vaccination. Researchers led by neurologist Jennifer A. Frontera came to the conclusion in their study around 2022 that the probability of suffering a neurological event after an acute corona infection is up to 617 times higher than after a corona vaccination.
In summary, the researchers write: “The study confirms previously identified rare safety signals after the corona vaccination and provides evidence of several other important results.” However, further research is required to confirm connections and assess the clinical significance.
This is the situation in Germany: 1.77 suspected cases per 1000 vaccinations
In Germany, the Paul Ehrlich Institute (PEI) is responsible for assessing and monitoring vaccines. In its final report on Covid-19 vaccinations, the institute writes that
192,208,062 vaccinations 340,282 reports of suspected side effects or vaccination complications were made.
This corresponds to 1.77 suspected case reports per 1,000 vaccinations. The PEI refers to the period between December 2020 and March 2023. At the time of reporting, the state of health had already been restored or improved in almost 42 percent, and not yet in 39 percent. Five percent reported permanent damage and 0.98 percent reported a death.
Specifically, 3,315 deaths were reported after the over 192 million vaccinations administered in Germany. Of these, 127 cases were assessed by the PEI as consistent, i.e. with a causal connection to the respective Covid-19 vaccination. For comparison: The Robert Koch Institute (RKI) assumes that more than 180,000 people have died from or with Covid-19 since the beginning of the pandemic.