The omicron mutation of the coronavirus caused the number of cases to skyrocket due to its easy transmission. Should the BA.2 subtype be of greater concern?
Munich – In December 2021, the omicron mutation of the coronavirus gradually became the dominant variant in the infection process, replacing Delta as the driving mutation of the pandemic. At first there were concerns about the new variant, which, according to initial assessments, was described as highly contagious. Studies confirmed this assumption, but at the same time they revealed the milder course of the disease compared to Delta and led to relief.
Another variant was discovered a few weeks ago. This time it was not directly another corona mutation, but much more a subtype of omicron – BA.2. Many people asked themselves whether this subtype is similar to the original omicron variant BA.1 or perhaps more dangerous.
Omicron subtype: According to Drosten, BA.2 has “a few more horsepower” – the greatest risk is again for those who have not been vaccinated
The first thing that comes to mind when you think of a new variant or sub-variant of the coronavirus is its infectivity. After all, this factor is decisive for how quickly the new mutation spreads in the population. With regard to BA.2, the virologist Christian Drosten commented that the subtype could actually be more transmissible than the previous omicron variant BA.1. He illustrated this using a car example: “One Mercedes somehow looks very stuffy and the other Mercedes has spoilers on it. But it’s still a Mercedes and still the same model.” But BA.2 has “a few more horsepower,” says Drosten.
The virologist appealed to that a study by the Danish Statens Serum Institut. In a study in late January, the institute said BA.2 was more contagious compared to BA.1. However, the increased risk of infection is particularly the case for unvaccinated people. “Vaccinated people are much less likely to become infected and transmit the infection,” the institute’s press release said about their research. In concrete terms, this means that if you are vaccinated, there is a lower risk of contracting BA.2. However, as with BA.1, there is still an elevated level in unvaccinated individuals.
Omicron subtype: According to experts, no difference in severity between BA.1 and BA.2 – WHO researchers also confirm
However, a partially easier transmissibility says nothing about the severity of the disease in the case of an infection with BA.2. Although there is no comprehensive data on the severity of the disease, initial assessments by several experts give hope that there are not too great differences between BA.1 and BA.2. The Danish institute already emphasized on January 20th that the first data show no change in the hospitalization rate for BA.2.
“With regard to the clinical characteristics, there is currently no evidence that infections with BA.2 differ from infections with BA.1,” also stated the most recent RKI status report from February 10th. According to virologist Christian Drosten, there are “no signs” of an increasing severity of the disease. Virologist Sandra Ciesek agreed: “Very early observations from Denmark suggest that there does not seem to be a great difference in the severity of the disease between BA.1 and BA.2.” Several WHO experts such as Maria Van Kerkhove and Boris also confirmed this Pavlin reported similar severity to BA.1 and BA.2.
Omicron subtype: Vaccines have comparable efficacy at BA.2 – still “significant protection”
A similar picture to BA.1 can also be seen for vaccination protection against the omicron subtype BA.2. Leif-Erik Sander, infectiologist and vaccine researcher at the Charité in Berlin, wrote on Twitter: “Protection against symptomatic infections is comparable after booster vaccination in sublines BA.1 and BA.2, according to initial data.” Sander referred to data from the “UK Health Security Agency”. Accordingly, the booster vaccination shows a similar effectiveness as with BA.1. There are no differences in the effectiveness of the vaccination, according to the British authority. In the background of these statistics, Carsten Watzl, Secretary General of the German Society for Immunology, spoke of a “reassuring” data situation.
International experts also drew attention to the effect of the booster vaccination on BA.2. The American medical professor David Agus emphasized on the US broadcaster CBS that the booster still offers “significant protection” against the omicron subtype. Another US epidemiologist Egon Ozer stressed The Guardiansvaccinations and boosters would continue to keep people “away from the hospitals and death” even with BA.2. (bb)
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