Omicron subtype BQ.1.1 – what is known about “Cerberus” so far?

From the information available to date on BQ.1.1, researchers can already draw initial conclusions as to what influence the variant could have on the course of infection and possible courses of the disease.

Incidentally, the name “Cerberus” comes from users of the short message service Twitter. There it has become common practice to give corona subtypes the names of mythological creatures – in addition to the hellhound “Cerberus” on Twitter there are also the “Hippogriff” or the “Centaurus” as names for subvariants of  SARS-CoV-2 .

Omicron BQ.1.1 – how does the subvariant influence the course of infection?

BQ.1.1 is a subvariant of BQ.1 and thus belongs to a new subline of the omicron subvariant BA.5. As with BA.5, the risk of infection is correspondingly high.

At the beginning of October, for example, the bioinformatician Cornelius Römer made forecasts for transmission compared to the previous variants of the  corona virus  . According to him, the increase in portability of BQ.1.1 is roughly comparable to that between omicron subtypes BA.1 and BA.2 or between BA.2 and BA.5. This means that the number of infections in a certain period of time increases slightly due to the spread of BQ.1.1 compared to the currently dominant subvariants BA.4 and BA.5. However, the difference is significantly smaller than between the Delta variant and Omikron.

Nevertheless, it can be assumed that BQ.1.1 will probably account for an ever larger proportion of new infections. In Germany, too, some diseases have already been identified that can be traced back to “Cerberus”. The latest data from the Robert Koch Institute (RKI) relates to calendar week 45. In this week, the proportion of BQ.1.1 in new infections was around 9 percent. For comparison: In calendar week 44, the variant accounted for around 8 percent of new infections.

The weekly doubling of infections with BQ.1.1 that was initially feared has probably not materialized so far, although the number of unreported infections is likely to remain high. As a result, fewer samples can be evaluated, which means that in many cases the causative virus variant cannot be determined.

How well are you protected by previous infections or vaccination?

Little is currently known about whether people who have already been infected with BA.2 or other omicron variants such as BA.5 could become infected again with BQ.1.1. However, this is probably possible due to the numerous mutations in BQ.1.1.

BQ.1.1 has five mutations on the spike protein, which allows the coronavirus to dock to human cells. This spike protein is a characteristic feature of the coronavirus, and the  immune system  is trained to recognize it through vaccination or a previous infection. If mutations change this spike protein, it becomes more difficult for the body to recognize the virus and fight it quickly. In this respect, the mutations BQ.1.1 enable a so-called immune escape to a certain extent, i.e. the subvariant is less well recognized by antibodies in the blood.

According to the opinion of experts, however, previous infections as well as the vaccination continue to offer a high level of protection against serious illnesses. This is because the B and T cells as part of the immune system as well as the so-called “memory cells” can trigger the formation of new antibodies against the coronavirus even after a long time and independently of changes in the virus variants on the spike protein.

According to the latest findings, antibody therapies are not effective

Since BQ.1.1 is a subline of subvariant BA.5, a fourth vaccination with a vaccine adapted to BA.4 and BA.5 is still useful for people from risk groups – especially with regard to the fact that previously established antibody therapies are used to treat severe courses according to the latest research results, do not strike effectively with BQ.1.1. In addition to vaccination, the scientists on whose study this statement is based therefore advise increased use of the corona drug Paxlovid® among members of risk groups.

What symptoms does “Cerberus” trigger?

So far, there are few well-founded statements about which symptoms are triggered by an infection with BQ.1.1. It can currently be assumed that symptoms will be similar to those of the previously widespread omicron variants. Signs include  headaches ,  runny nose ,  sore throat  and dry  cough . In addition, an increase in the course of the disease with  nausea ,  diarrhea  and vomiting is reported. So far, however, there is no comprehensive evidence for this.

However, on the basis of the (albeit still limited) data available so far, there is at least no reason to assume that BQ.1.1 triggers more severe disease progressions than the omicron variants that have dominated to date.

What is the sub-variant XBB all about?

So far, Omikron XBB has played no role in the infection process in Germany. However, the sub-variant of the corona virus has already been detected in 17 countries, and it is particularly widespread in Asia. In Singapore, XBB has already displaced the previously dominant BA.5 subtype. XBB now accounts for over half of new infections in the country. The proportion has more than doubled within a week.

XBB has seven mutations on the spike protein, allowing it to partially evade the immune system. So far, however, there is at least no evidence that XBB causes more severe disease progression than BA.5.