The omicron variant BA.5 is spreading in Europe

A new wave is also starting in Switzerland and Germany. We have put together the most important facts about the new variant.

A self-test also detects an infection with the variant BA.5.

Christian Beutler / Keystone

The BA.5 subvariant of the omicron coronavirus has now triggered new waves of infection in several European countries. The USA has also been reporting a renewed increase in the number of cases for a few days. First, the BA.5 variant caused a fifth wave in South Africa at the beginning of May. However, this has so far been smaller than the omicron wave of last winter and is already subsiding again.

Then, in the last few days, news from Portugal destroyed the hope that Omikron BA.5 would not be able to establish itself in Europe. There, the 7-day incidence of new infections per 100,000 inhabitants rose to almost 1,400 (for comparison: in Germany the value is 447, in Switzerland over 120, as of June 14). In Portugal are now according to the National Health Institute 87 percent of all new infections can be attributed to BA.5.

And now BA.5 is apparently also conquering Switzerland and, with a little delay, Germany. At the moment there is already a clear increase in the number of new infections.

Another rise

New infections confirmed daily in Switzerland and Liechtenstein, 7-day average up to 3 days ago

And there are two other key indicators that a new wave is building. Firstly, the proportion of positive Sars-CoV-2 tests – i.e. tests that confirm a new infection – has risen sharply in recent weeks. The experiences of the two pandemic years show that a higher proportion of positive tests indicates an increasing number of new infections. Since not all people with Covid 19 symptoms can be tested, not all infections are recorded. However, the rate of positive corona tests is a meaningful substitute value.

The positivity rate increases sharply

Percentage of positive Sars-CoV-2 tests (7-day average) in Switzerland and Liechtenstein

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Certification requirement for restaurant interiors and leisure facilities (September 13, 2021)

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Tests for asymptomatic will be charged (October 10, 2021)

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Costs for rapid antigen tests will be covered again (December 18, 2021)

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Abolition of the obligation to obtain a certificate (February 17, 2022)

Secondly, the number of reproductions has increased significantly again in the last few days. It is around 1.3 according to the latest figures from May 24th. This number indicates how many people an infected person infects. If it stays below 1, the pandemic will die down. However, if it is well above 1, a new wave is building up.

The number of reproductions is well above 1

Estimate of the number of reproductions in Switzerland up to 10 days ago, based on the confirmed cases in Switzerland

BA.5 drives the new wave

According to the available data, Tanja Stadler from ETH Zurich and Isabella Eckerle from the University of Geneva assume that a good half of all new corona infections in Switzerland can be traced back to BA.5. So BA.5 now dominates the action.

However, since only very few virus genomes have been decoded in Switzerland and there is generally little surveillance, this can only be estimated at the moment, both experts emphasized when asked. In Germany, more than half of all new infections are expected to be triggered by BA.5 in mid-June.

Because of the low monitoring, the increase in BA.5 in Switzerland was only noticed when this subvariant had already accounted for 5 percent of all new infections, explains Stadler. In Germany, on the other hand, attention was drawn to just 1 percent of all cases.

The number of people infected with BA.5 viruses has increased steadily in recent weeks. Most recently, it doubled in Switzerland in less than two weeks. Germany reports similarly rapid increases. It can therefore be assumed that in Switzerland and Germany the Omicron variant BA.5 drives the wave that is just emerging.

Is BA.5 more dangerous?

It is currently completely unclear how high the BA.5 wave will be in this country and how many people with severe Covid 19 disease caused by BA.5 will have to go to the hospital. In South Africa, there were significantly fewer hospitalized patients during the BA.5 wave than in the earlier Omicron wave.

In South Africa, the BA.5 wave resulted in only a few serious illnesses

Covid-19 indicators in South Africa (7-day average), each as a percentage of their maximum value

patients in intensive care units

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First omicron wave in South Africa

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Start of new wave with Omicron subvariant

In Portugal, on the other hand, the number of hospitalized patients has increased by 27 percent in the last week, and the death rate has also increased. Older people were mostly affected. It is still unclear whether the increase is solely due to the many new infections. Portuguese experts suspect that vaccination protection has decreased so much, especially among older people, that they are again more susceptible to serious illnesses.

In Portugal, the number of severe corona diseases is also increasing again

Covid-19 indicators in Portugal (7-day average), each as a percentage of their maximum value

patients in intensive care units

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First omicron wave in Portugal

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Start of new wave with Omicron subvariant

In England, too, the number of Covid 19 patients who have to go to the hospital has been increasing for a few days. There, the rate of hospitalizations increased by 33 percent compared to the previous week. However, the total number of people hospitalized with Covid-19 is still significantly lower than during the last major corona wave in April 2022.

Again more hospital admissions in England

Daily confirmed hospitalizations in England, 7-day average

Initial estimates for Germany also show a slightly higher hospitalization rate. Stadler and Eckerle emphasize that the next few weeks will see how BA.5 will affect this country. Since the respective conditions such as vaccination rate, number of recovered people, previously dominant corona variants, age of the population and other things are very different in the individual countries, it will become increasingly difficult in the future to determine the effects of a certain variant in one country from the type of wave in another derive country.

What is certain is that the new subspecies is even more contagious than its predecessors. Tulio de Oliveira, chief virus monitor at South Africa’s Center for Epidemic Response and Innovation, believes that BA.5 can help protect against immune responses generated by vaccination or past infection escape a little better can. Therefore, it can spread faster and displace the other variants.

Protect vaccination or recovery?

Presumably neither a vaccination nor a previous omicron infection reliably protects against a BA.5 infection. Firstly, the protection against infection decreases within a few months anyway. Second, the individual omicron viruses differ at some important points in their genome. This means that the immune system, built up against earlier variants, no longer recognizes the new one as well.

So it may very well be that someone who had an omicron infection in January will now become infected again. But the data available so far shows that vaccination or recovery largely protects against serious Covid-19 disease – no matter what variant triggers it.

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