Study by virologist Eckerle on immune escape

Everyone was always talking regarding autumn. But as is so often the case, Corona thwarts all plans. The summer wave is here in full force. Fortunately, the increase in hospitalizations is limited. But the wave makes it clear: the high level of immunity in the population, which there is thanks to vaccination and previous illnesses, has not put an end to Corona.

One reason for this is omicron. Just a few days ago, a team from the Geneva University Hospital HUG led by virologist Isabella Eckerle published a new study that shows that everything is different at Omikron. summarizes the most important things.

What is secured

There is no absolute protection once morest being infected with Corona once more following vaccination or infection. “When it comes to coronaviruses, we have to say goodbye to the idea that you get infected once in your life, like measles, for example, and then be protected for the rest of your life,” emphasizes Isabella Eckerle. In principle, reinfections are always possible; when and how often they occur depends on the one hand on the type of virus that is currently circulating and on the other hand on the immune system of the person affected.

It is also clear that the latest corona variant Omikron is not the hoped-for solution to the pandemic, in which a mild variant ensures little disease burden and permanent, broad immune protection.

What the data suggests

In principle, protection is always best once morest the type of virus that you have already been infected with, says Eckerle. So anyone who was infected with the delta wave is also best protected once morest the delta variant. Protection once morest other variants is slightly lower, but still there.

The big exception, however, is Omikron, as Eckerle’s team has now found out. “Omicron always has new tricks up its sleeve,” says the virologist. The researchers investigated how well infections with earlier variants protect once morest the omicron subtype BA.1. And the data shows that the so-called immune escape is high. This means: Omikron manages to bypass the antibodies from previous infections. And that applies to antibodies from all previous variants whose names come before omicron in the Greek alphabet.

However, the study was limited to blood samples from just 120 people. There were particularly few when it came to the rarer corona variants such as gamma, which first appeared in Brazil. In addition: The omicron subtype, which is responsible for the current summer wave – we are already at BA.5 – was not yet the subject of the study. However, it is already clear that BA.5 also has tricks to bypass the antibodies from previous infections by means of mutations.

Protection through vaccination is better than a previous infection, and protection through vaccination plus infection is the best of all – although Omicron has immune escape advantages here too. According to Eckerle, the increased protection is due on the one hand to the fact that the body produces more antibodies following a vaccination than an infection – around ten times as many. In addition: “Anyone who is vaccinated usually had two doses plus a booster. So the immune system has come into contact with the surface protein of the virus at least three times.” The immune system is then armed accordingly.

What does that mean for the future

“We are still in an unstable situation,” emphasizes Eckerle. Apart from the fact that you can get reinfected repeatedly, in addition to the short-term illness, there is also a risk of catching long-term consequences – Long Covid – in the event of an infection. In addition, with the currently dominant omicron subtype BA.5, there are initial indications that more severe courses might become somewhat more common once more.

You can only relax to some extent if the virus does not produce any new mutations for a long time. That’s not the case yet – because the virus might still have some new tricks up its sleeve. “The fall does worry me,” says Eckerle. In addition to Covid, experts are also expecting many cases of flu once more, and the health workers will be exhausted.

She does not call for a mask requirement, but emphasizes: “People should be recommended to protect themselves.” Vaccines adapted to Omikron would also soon become important.

What does that mean for the booster

The study itself says nothing regarding this, since the effect of a second booster vaccination has not been examined. Whether the booster is also necessary for younger people cannot be concluded from this, as Eckerle emphasizes. It is known from other studies that a booster vaccination is recommended for over 60-year-olds.

She does not want to comment on the fact that the second booster in this country is only recommended from the age of 80: “Young people are not forbidden to be vaccinated once more”. But as far as the general population under 60 is concerned, the data is not yet clear.