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This is the conclusion of the Austrian virologist Florian Krammer of the Icahn School of Medicine at Mount Sinai in New York (USA) in an abstract article in the journal “Nature”. However, many questions remain. Although there is not yet an approved vaccine against a pathogen of the coronavirus group in humans and the development of the vaccine takes around 15 years under normal circumstances, the prospect of a rapidly available marketable active ingredient in a year to a year and a half was relatively soon. after the start of the corona pandemic in the room. Given the development at “record speed”, the scientist, who already presented an antibody test for the new coronavirus in March, even considers it possible that the vaccines will reach the market this year.
Krammer describes it as highly likely that the candidates from Moderna, Pfizer and AstraZeneca will have the necessary protective effect against the pathogen and are also licensed in the US and Europe if they prove to be safe enough. In this particular context, the pharmaceutical company AstraZeneca had to discontinue its studies with a vaccine due to an unexplained illness in a test person. In any case, it is possible that these first vaccines will later be replaced by other active ingredients that show a similar effect, but are associated with fewer side effects, admits Krammer, who still identifies some factors of uncertainty in the unprecedented development process.
There are still questions about the role of vaccine administration, which uses many different approaches. All advanced candidates will be administered intramuscularly. This leads to a strong production of IgG antibodies, which are actually formed quite late in the course of an infection. Although this type of antibody protects the lower respiratory tract, i.e. the lungs, this type of administration has no effect on the number of IgA antibodies formed earlier in the course of a respiratory infection. They are found mainly on the mucous membranes of the upper respiratory tract, where they inhibit the pathogen. Vaccination may protect the lower respiratory tract but not the upper respiratory tract.
“This can lead to vaccines that protect people from a symptomatic course, but still allow the virus to spread,” even if the likelihood of transmission was still reduced, Krammer said. If it still had active ingredients that can be administered through the nose, the upper respiratory tract would also be better protected. However, there are few such candidates.
So far, it appears that a naturally occurring Covid-19 infection leads to a “normal” immune response in which the number of antibodies to the pathogen decreases somewhat over time, but not dramatically. It is not known how long a vaccine of any type protects effectively, says the virologist. It could also be that vaccination protection is lower in older people who are at higher risk. On the other hand, many candidates have been able to trigger relatively strong side effects so far, raising question marks about use in children who are more susceptible to this.
Last but not least, there are also questions about how global supply can be guaranteed. It is good that vaccines are being worked on with different approaches in many countries because no single supplier will be able to guarantee such a complete supply, emphasizes Krammer, who, among other things, identifies possible bottlenecks in the range of syringes or glass containers. Even the cold storage required for some developments often cannot be guaranteed in less developed countries. For the virologist, therefore, it is quite conceivable that in the end inactivated SARS-CoV-2 pathogen vaccines, which are manufactured in China, India or other countries, will eventually be used in many countries. An advantage of this approach is that these vaccines could also be produced more easily in countries without high technology.
