The front runners have long hurried. With vaccination rates of sometimes well over 75 percent, countries such as Portugal, Ireland, Spain and Italy have been a respectable distance from Austria for months. In this country, only 64 percent of the total population are considered fully immunized because they have either been vaccinated with Moderna, Biontech / Pfizer, AstraZenca or Janssen (Johnson & Johnson) in accordance with the manufacturer’s specifications or have received a single sting after a corona infection.
Despite almost 800,000 people who have recovered since the beginning of the pandemic, the number of people in Austria who are protected from infection with the coronavirus is in fact likely to be below the official vaccination rate. The team around the simulation researcher Niki Popper assumes in its current “model-based estimate of the degree of immunization in Austria” that the proportion of immune systems in the total population is just under 61 percent.
In addition to people who were unable to build up an adequate immune response despite being vaccinated, those who have recovered are responsible for this. The group, which owes its immunity exclusively to a discovered or undiscovered Covid disease, makes up around nine percent of the total population, according to Popper. However, despite the increased number of infections due to the fourth wave, the number of people protected in this way is significantly lower than it was a few months ago. In April, the rate was around 15 percent, because those suffering from the previous great winter waves were not yet affected by a waning immune response, but still enjoyed full protection.
Popper and the experts from dwh, a spin-off from the Technical University (TU) Vienna, are each assuming a relatively high number of unreported cases. In addition to the almost 50,000 known active cases on November 1, they assume about 175,000 more undetected infections.
Degree of immunization clearly expresses the number of reproductions
The shrinking pool of immune recovered is also noticeable in the so-called reproduction number. According to the model calculations, the current immunization rate depresses this factor by about 52 percent compared to a completely unprotected population. The delta variant that is dominant in Austria, which in turn is about 50 percent more contagious than the alpha variant that was circulating before, counteracts this. “Without the immunized, the situation would be correspondingly worse,” explains Popper.
If, however, the proportion of immunized were to increase a little further, this could very quickly lead to a sharp reduction in the number of cases because the virus is running out of infectable people who are now too plentiful. According to Popper, this is still the most effective measure of the pandemic fight. The simulation expert is convinced that all other containment measures would result in far smaller reductions. (rs)