COVID vaccination: more side effects due to vaccine change?
Since sinus vein thrombosis has increased in younger people in particular after a corona vaccination with AstraZeneca, STIKO recommends switching from the vector vaccine to an mRNA vaccine  (BioNTech/Pfizer, Moderna) for this group of people. However, experts suspect more side effects with the heterologous vaccination scheme.
Vaccine switch from AstraZeneca to mRNA vaccine: more frequent reactions possible
While vaccination reactions mostly occur after the second vaccination with mRNA vaccines such as BioNTech/Pfizer and Moderna, with AstraZeneca these occur more frequently after the first dose.
Heterologous vaccination can also lead to temporary side effects. English scientists are currently analyzing the consequences of the vaccine change. The first interim results have already been published in the scientific journal “The Lancet”.
The experts compared a total of four different vaccination schemes:
- First vaccination with AstraZeneca, second vaccination with BioNTech/Pfizer
- First and second vaccination with vaccine from AstraZeneca
- First vaccination with BioNTech/Pfizer and second vaccination with AstraZeneca
- First and second vaccination with the mRNA vaccine from BioNTech/Pfizer
At the time of the study, the participants did not know which vaccine combination was used. The experts examined both a vaccination interval of four weeks and three months. The data so far are only available from the short vaccination interval of four weeks. It should also be mentioned that all test subjects were 50 years or older.
In particular, those vaccinated with the AstraZeneca and BioNTech/Pfizer scheme suffered more frequently after the second vaccination:
Combination of vector and mRNA vaccine: More reactogenicity
According to initial findings, a vaccine change leads to frequent and pronounced vaccination reactions, which are also referred to as reactogenicity. The order of the two vaccines is not decisive in this context.
If one compares the heterologous vaccination schedule with the homologous one, the risk of a vaccination reaction when switching vaccines is increased by up to 20 percent. These vaccination reactions can occur more frequently:
- Fever
- chills
- joint pain
- exhaustion
- Muscle aches
- general malaise
The vaccination reactions mostly lasted only temporarily and were particularly observed in the first 49 hours after the second vaccination. They are therefore not classified as a cause for concern.
The test persons were informed that taking paracetamol  can alleviate possible vaccination reactions. According to STIKO recommendations, however, the painkiller should  not be taken until six hours after the vaccination.
All results of the study on vaccination reactions and side effects of the vaccination will be published in June. In addition, further vaccine combinations with the vaccines from Moderna and Novavax are already being investigated.