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Currently, more than 40 vaccines are being clinically tested in humans, according to the World Health Organization, WHO.
So far, only limited data have been obtained from ongoing studies, these include data from animal studies and clinical data from smaller studies in humans. The results that have been published are not yet enough to draw conclusions about the safety of vaccines, says Charlotta Bergquist, vaccine coordinator for the Agency for Medical Products.
– In these small studies, common reactions are expected, which are also seen with other vaccines, he says.
It mainly deals with pain, swelling and redness at the injection site, as well as physical symptoms such as fever, fatigue, headache, nausea, muscle aches, signs that the immune system reacts to the vaccine.
This spring, for example, vaccine maker Moderna released its first results, showing that the vaccine generally produced mild side effects such as muscle pain, headache, chills, fatigue, and injection site pain. This summer, it was time for Astra Zeneca, which reported no serious side effects, but just over 70 percent had suffered from a fever or headache.
Several of the covid-19 vaccines developed with completely new or relatively unproven technology. An example of the latter is the Astra Zeneca virus vector vaccine, which weakens a common cold virus so that it cannot cause illness. When the virus is injected into the body and invades cells, the cells begin to produce viral proteins against which the immune system produces antibodies.
In early September, the Astra Zeneca study was temporarily stopped after a UK participant contracted transverse myelitis, a nerve disease that can occur after vaccination. The study has now been resumed in all affected countries except the United States, as it was deemed safe to continue. The question is whether this will be important when the European Medicines Agency EMA, which is assisted by the Agency for Medical Products, has to make a decision on a permit.
– The UK authorities have reviewed and decided that the study will continue, but we will review it when we receive the request from Astra Zeneca, says Charlotta Bergquist.
So-called DNA or mRNA vaccines, in which pieces of genetic material from the coronavirus are injected, are even less well proven. So far, there is no vaccine made with this technology on the market.
According to Charlotta Bergquist, more unusual side effects of these vaccines cannot be ruled out.
– I would not rule out more unusual side effects even for those produced by known technology, but there is still more uncertainty about the side effects of these vaccines.
Johnson & Johnsons Vaccination Test.
Photo: Cheryl Gerber / AP
Vaccinforskaren Matti Sällberg, Professor of biomedical analysis at Karolinska Institutet, he is working on the development of a DNA vaccine and hopes to begin clinical trials this spring. He agrees that there are several questions around new technologies.
– It is clear that there could be other side effects other than those seen with traditional vaccines. But so far, the side effects of the new vaccines are similar to those seen in those developed with classic vaccine technologies.
Unusual side effects are not normally detected until the latest phase 3 studies, for which data have not yet been presented. Truly unusual side effects are usually not found until mass vaccinations have begun. That was probably what happened ten years ago with the Pandemrix swine flu vaccine, where the diagnosis of narcolepsy increased dramatically in those who injected themselves.
Matti Sällberg points out that practically everything that works in medicine has side effects.
– But they must be acceptable. The benefits must outweigh the side effects.
In August, Sweden’s national vaccine coordinator Richard Bergström said he expects vaccination to start early next year, if all goes according to plan.
Read more:
Sweden Coordinator: Here are the most promising vaccines against covid-19
Karin Bojs: Therefore, vaccines must take their time
