Crown: development of variant B.1.1.7 and mutations

7 points about the current development of mutant viruses (not very encouraging)

The B.1.1.7 virus variant continues to spread rapidly. It has not only become the dominant mutation in Switzerland. This is not good news for fighting the virus. Here are the seven most important points about the current situation.

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Development in Switzerland

Basically, a virus is constantly mutating. Therefore, the risk that the measures are no longer sufficient with a variant remains latent. However, with the monitoring system, one can recognize as soon as a variant occurs in large enough quantities, and Switzerland is one of the first when it comes to testing, BAG said Tuesday. Patrick Mathys, Head of the Crisis Management and International Cooperation Section, also commented on the situation with the variants: “80 percent of detected infections can be traced back to these variants.”

Therefore, virus mutations continue to increase in Switzerland. As Emma Hodcroft, an epidemiologist at the University of Bern, also confirmed last night, the British variant B.1.1.7 in particular is spreading very rapidly in Switzerland and already accounts for around 80 percent of cases (dark red) :

By March 8 at the latest, the British variant dominated with 79 percent, a month earlier it was 50 percent, at the beginning of the year around 10 percent.

What does this mean for the number of cases in the next few weeks?

Unfortunately, this is difficult to predict because the infection status is uncertain. Recently, the number of infections has increased slightly. At yesterday’s press conference, the BAG announced that the figures will double in four weeks. Which brings us to mid-April with almost 3,000 cases a day.

A third wave cannot be ruled out for now. Mathys did not want to say clearly Tuesday that the third wave had started, although there are many models to suggest it.

What is the Working Group’s forecast?

The latest scientific update from the federal task force is March 9. There it is confirmed that the greater the frequency of the B.1.1.7 mutation, greater efforts are required.

In terms of dynamics, the Lake Geneva region is a week or two ahead of Switzerland as a whole. In the current working group model, the number of cases with B.1.1.7 continues to increase. Actual case numbers are roughly on this curve, even if they flatten out a bit in the middle (be careful, the graph below stops at the end of February).

Are the variants of the virus now more deadly or not?

That has not yet been definitively clarified. On Monday, a study was published to the effect that mortality within four weeks of a positive test was higher in the case of an infection with the B.1.1.7 variant. As an example: in a man aged 55 to 69 it increases from 0.6 to 0.9 percent. Which doesn’t seem like much, although the increase is high.

Other indications also suggest that mortality is higher. When asked Tuesday, Patrick Mathys said: “The British variant may actually be more deadly, we are awaiting further studies.” The findings would be more reliable in the coming weeks.

What does this mean for herd immunity?

Patrick Mathys, Head of the Crisis Management and International Cooperation Section, does not want to give a fixed percentage that is required for herd immunity. One thing is for sure: it will be achieved when enough people have formed antibodies through infection or through a vaccine.

The variants also play a role in herd immunity. Mathys says: “We assume that the original variant has a transmission rate of 3 to 3.5, which means: each person infects between 3 and 3.5 people without any measure.”

To be able to live without (self-limiting) measures, the number of transmissions would have to be less than 1. “About two-thirds of the population would have to be immune,” says Mathys.

In the case of variant B.1.1.7, a transfer advantage of around 50 percent is currently assumed. One person infects about 4.5 more people. “We are 80 percent or even more of those who should be immune to herd immunity.” However, as is well known, this 80 percent is not the short-term goal. The current approach is to protect groups at risk. It is not yet clear how many people will actually be vaccinated in Switzerland, even after several surveys.

How much does the vaccine protect?

The Pfizer / BioNTech and Moderna vaccines also protect against variant B.1.1.7. Based on current knowledge, the vaccines no longer work as well with the South African and Brazilian variants. The AstraZeneca preparation provides only weak protection against the South African variant, Pfizer / BioNTech and reduced Moderna.

How is it in other countries?

Variant B.1.1.7 was developed predominantly in practically all the countries examined. In Germany, for example, a sharp increase in the number of cases due to the B.1.1.7 virus is expected, as RKI statistician Andreas Hicketier recently tweeted:

Emma Hodcroft also published her analysis with the proportions of the B.1.1.7 variant, showing how this mutation is widespread in Germany, among other places.

However, the developments are much more striking, for example in Great Britain or Ireland, where the B.1.1.7 virus has displaced virtually everyone else. The advance is also huge in Denmark, the United States, Belgium and Italy.

Here we show the evolution in selected countries with data from Emma Hodcroft. The dark red area is variant B.1.1.7.