Given the large number of vaccine breakthroughs, the question arises as to whether coronavirus vaccinations are even suitable for preventing the virus from spreading. A direct answer cannot be given because chains of infection are no longer systematically tracked. Therefore, in the case of a new infection, it is not certain whether it is due to contact between vaccinated or unvaccinated people.
In order to arrive at an assessment nevertheless, researchers led by Dirk Brockmann from Humboldt-Universität Berlin have simulated the spread of the coronavirus in the German population. They come to the conclusion that it is indeed the unvaccinated who are driving the infection dynamics in Germany. According to their study, only one in ten new infections took place between two vaccinated people. At least one unvaccinated person was involved in the rest of the new infections – mostly as the one from whom the infection originated.
Although unvaccinated people are clearly in the minority with about a third of the population, they often cause new infections to them disproportionately. The researchers simulated the infection in Germany in the days between October 11 and November 4, 2021. In these weeks, the nationwide incidence began to rise sharply.
In an unreviewed article, Brockmann and his team provide details of their study. How well a vaccine slows down the spread of the virus depends above all on its effectiveness against infection. The research group simulated two scenarios. In the first, she estimated the effectiveness at 92 to 72 percent depending on the age group, in the second scenario at only 60 to 50 percent.
Few infections affect those who have received vaccinations, despite low vaccine effectiveness.
The assumption in the "optimistic" scenario 1 resulted in a little more vaccination breakthroughs than actually reported, and in this respect it coincides with the infection in Germany, the scientists write. But even with the assumption of an even lower vaccine (scenario 2), infections hardly take place between vaccinations - in concrete terms: only 16 out of 100. The virus not only passes on not only less often because they are less likely to develop, but also because they less long contagious than these are.
As a result, the researchers believe that 76 percent (scenario 1) and 67 percent (scenario 2) of new infections are caused by unvaccinated people.
It remains unclear how Brockmann and his team are performing, how to assess the influence of unvaccinated children and adolescents. If one assumes a reduced infectivity compared to adults, one arrives at the above figures. If, on the other hand, it is assumed that children and adolescents pass on the virus as quickly as adults, the group of unvaccinated people noticeably reinforces the infection process once again. Unvaccinated then cause more than 80 or more than 75 percent of new infections.
The same applies if one assumes that vaccinated and unvaccinated people stay among themselves. In this case, the unvaccinists drive the infection dynamics even more than the figures mentioned above.
As a result of its investigation, the team recommends ensuring that there is less contact between unvaccinated people. A reduction of contacts in this group by a quarter would already be sufficient to reduce the R-value to below 1, which would result in a slow decline in incidences. For this, the (vaccinated) majority of the population would then no longer have to accept any further restrictions.
