Is a “killer variant” threatening in autumn?

After Federal Health Minister Karl Lauterbach (SPD) warned of a possible “killer variant” of the Corona virus in autumn, experts stress the unpredictability of the development.

“No expert can currently say for sure which variant we will get in autumn,” intensive care physician Stefan Kluge from the University Medical Centre Hamburg-Eppendorf told the Funke Mediengruppe. “But we should be prepared for the possibility of another variant coming along that leads to a higher severity of illness than is currently the case with the Omikron variant.“

Lauterbach had spoken of a possible “hard autumn” in the “Bild am Sonntag” in view of the vaccination gap. “It is quite possible that we will get a highly contagious Omikron variant that is as deadly as Delta. That would be an absolute killer variant.” The minister spoke of shorter and shorter intervals between dominant variants, which he said made preparation more difficult. Various Omikron sub-variants, which he found worrying, were currently developing.

Lauterbach is probably alluding to several Omikron sublines that have recently come into focus. To begin with, BA.2 is predominant in Germany, whereas previously it was BA.1. Recently, BA.4 and BA.5 also emerged, which the World Health Organisation (WHO) also classifies as worrying as part of Omikron. According to the WHO, evidence came from South Africa and some European countries. Both sublines showed partly different characteristics than other Omikron variants, they said – but details are still open.

In addition, a possibly even more easily transmissible Omikron sub-variant has been described in Great Britain – but much is also unclear about the subtype called XE. According to the WHO, it is a mixed variant of BA.1 and BA.2, a so-called recombinant. These can form not only from two subtypes, but also from different variants: for example, from Delta and Omikron, which has also already been observed and sometimes called Deltakron. Recombinants can arise when a patient is infected with different Sars-CoV-2 pathogens at the same time.

What is the situation in Germany regarding the development of BA.4, BA.5 and XE? Open. In previous weekly reports, the Robert Koch Institute (RKI) has not been so specific about subtypes.

“We currently have a mortality rate of less than 0.1 percent with Omikron, comparable to the flu,” intensive care physician Kluge told the Funke Mediengruppe. Even though he urged preparations for a possible worse variant: there are voices that consider it rather unlikely that the virus will become deadlier again in the future, especially for those who have been vaccinated. Experts urge, among other things, that as many people as possible over the age of 60 should be vaccinated, just in case.

The breadth of possibilities and the uncertainty are shown by four scenarios that the British scientific advisory group SAGE presented for Great Britain in February: According to them, Sars-CoV-2 could come back in the autumn in the best-case scenario without more changed characteristics. In the worst case, however, another large wave with many severe cases is conceivable. Between the two scenarios, the group names a rather optimistic and a rather pessimistic one – and emphasises that other courses cannot be ruled out.

The only thing that is fairly certain is that Corona will be with us for some time, also in the form of new variants. How bad these will be depends on several factors. The SAGE group sees growing importance in the question of waning immunity and immune escape – the ability of the virus to evade antibodies from the vaccinated and the recovered. Previous waves, they say, have been driven primarily by increasingly transmissible variants. Some researchers, however, believe that the high level of Omikron can hardly be increased.

Original text: Gisela Gross, dpa

Translation: Mareike Graepel