FAQ
Increasing case numbers due to omicron subtype BA.2: You should know this about the subvariant
The omicron subtype BA.2 is spreading in Germany.
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More and more people are becoming infected again with the corona virus, especially with the omicron subvariant BA.2. The Robert Koch Institute writes that a further increase in the number of cases cannot be ruled out.
The Omikron sub-variant BA.2 has been on the rise in Germany since the beginning of the year. The figures from the Robert Koch Institute (RKI) make this very clear. Just a week ago, 38 percent of new infections were due to this omicron subtype. The current weekly report of the RKI shows an increase to 48 percent. This means that almost half of the new infections are now attributable to the BA.2 subtype.
Already at the end of last year, the subtype spread quickly in other countries, for example in Denmark, like the star reported. What we now know about the subtype and what its spread means. The most important questions and answers.
What is the subtype BA.2 exactly?
The BA.2 subline is a subline of the omicron variant. So far, people in Germany have been most infected with subvariant BA.1. Loud World Health Organization (WHO) BA.2 differs in its genetic sequence from BA.1. For example in the spike protein, which the virus uses to attack cells in the human body.
Is subtype BA.2 more dangerous than BA.1?
The RKI writes: “In populations with high immunity from vaccinations or previous infections, no differences in disease severity were found between the omicron sublines BA.1 and BA.2.” Scientists from South Africa came to the conclusion in an analysis that infections with the omicron subvariates BA.1 and BA.2 do not differ significantly in terms of disease severity. The researchers analyzed data from more than 90,000 people who were infected with omicron between December and January. At that time, BA.2 was already clearly on the rise in South Africa. In an older one investigation from Japan researchers had examined the BA.2 subtype in hamsters in the laboratory and found an increased disease severity compared to BA.1.
However, neither the weekly report of March 3, 2022 by the RKI nor the study from South Africa are meaningful with regard to the severity of the disease in people who have not yet had a Covd-19 infection or who are not vaccinated. Because in South Africa, a large proportion of the people have either already been infected or have been vaccinated. And the RKI’s statement only refers to a well-immunized population.
Is BA.2 more contagious?
The RKI writes that the subtype BA.2 is easier to transfer than the subvariant BA.1. Also the Expert Council of the Federal Government confirmed that the subtype was easier to transmit as early as mid-February.
“The steady increase in the prevalence of BA.2 in several countries suggests that it has a growth advantage over other circulating variants,” Mads Albertsen, a bioinformatician at Aalborg University in Denmark, tells the journal “Nature”. Even Data in preprint from Denmark draw a similar picture: Researchers have examined the infections in households. The result: unvaccinated, vaccinated or already boosted – a person who is exposed to subvariant BA.2 is more likely to be infected than BA.1. However, the study also shows that those who have been vaccinated and boosted pass on BA.2 and infect others somewhat less frequently than with BA.1.
Do vaccinations still protect?
in the UK Health Security Agency report states: “Vaccine efficacy against symptomatic disease was similar for Omikron’s BA.1 and BA.2 sublines.” According to the report, the vaccinations also protect against severe courses at Omikron. According to the RKI, “no differences in the severity of the diseases were found between the omicron sublines BA.1 and BA.2 in a “population with high immunity through vaccination or surviving infection.”
Can I get infected with BA.2 even though I already had BA.1?
First data of a Danish preprint show that although it is possible to become infected first with BA.1 and then with BA.2, the researchers conclude from their data that it rarely occurs. Younger, unvaccinated people in particular could be re-infected with BA.2 after infection with subvariant BA.1.
What does the sub-variant mean for the course of the pandemic in Germany?
How exactly the situation will develop depends on various factors and not just on the virus variant. For example, the frequency of contact due to upcoming loosening or moving meetings outside when temperatures are spring-like. The RKI writes in its weekly report (dated March 9, 2022): “It can be assumed that the current renewed increase in transmitted Covid-19 cases is due to the easier transferability of sub-line BA.2 and the withdrawal of contact-reducing measures a further increase in the number of cases cannot be ruled out. The further course of the pandemic depends to a large extent on how behavior in the population changes and to what extent possible contacts relevant to infection increase.”
The modeler Kai Nagel and his team at the TU Berlin have in her last report different scenarios outlined. In the best case, the omicron wave with the BA.2 subtype would at most reach the level of the BA.1 wave of mid-February. In the researchers’ most negative scenario, the BA.2 wave would be 2.5 times more violent than the wave with subvariant BA.1. In the researchers’ model, this would be the case if leisure activities were greatly increased and a previous infection with BA.1 did not protect well against the subtype BA.2, i.e. there is very low cross-immunity.
This article was first published on 3/4/2022 and last updated on 3/11/2022.