According to a model calculation by simulation researchers in early August, an estimated 70 percent of the population was estimated to be immune to infection with the dominant subtypes of the omicron variant of the SARS-CoV-2 pathogen (BA.2 and BA.4/5). in Austria. The level in the monthly “model-based vaccine coverage estimate” was last this high between March and May. Future estimates are questionable due to changes in pandemic data.
The team led by Martin Bicher of the Technical University (TU) Vienna and the company dwh, a spin-off of the TU, notes that on the reporting date (August 1), “about 72 percent of the Austrian population against the Omikron BA used to be. .2 subtype immune”. If you look at the BA.4/5 subvariants, you are slightly below that at about 70 percent. These immunity values are currently pushing the effective reproductive rate – that is, the average number of people infected by an infected person – between 65 percent from BA.2 and 63 percent in view of BA.4 / 5. The analysis is based on international scientific studies and on a “highly accurate” look at reinfection data, depending on the pathogen variant from Austria, related to vaccination and infection statistics, explains Bicher.
High level due to infections
For the most part, the reason for the currently comparable high level is the infections that large parts of the population have experienced in recent weeks and months. In contrast, vaccinations and boosters have played an important role in protecting against severe disease progression since the omicron variant became dominant.
The now calculated, but significantly higher immunity levels compared to early June and July are “epidemiologically meaningful”, according to the simulation researcher. The BA.4/5 wave has already passed its peak. The ebb is due to transient saturation effects – the virus therefore has no more potential “victims” in the immediate vicinity due to an overall boost in immunity. However, according to the model calculations, the situation will change again with the return of holidaymakers and the decline of the positive seasonal effects in the autumn.
Estimates very difficult in the future
However, the researchers are also struggling in this area in coping with the pandemic with the most recently reported data. The number of tests and the number of infections documented in this way fell sharply, especially around the end of the quarantine. As a result, the immunity estimate also decreases slightly. Whether all this corresponds to reality is highly questionable. It follows that in the current data situation it is becoming increasingly difficult to maintain the reporting system that has been tried and tested for years, according to the scientist. What is needed now is a wastewater monitoring system that functions as quickly as possible or a reliable sentinel station with general practitioners, such as in the case of flu, if you want to monitor the epidemiological situation in the future.
Towards the fall, the recently high number of Covid 19 infections and the resulting temporary immunities should be seen as an advantage, Bicher says. Ultimately, this is a good condition for a more balanced distribution of the burden of disease on healthcare in the coming months.