The fact that the pandemic is not over yet is shown by the recently increasing incidences in the summer months. The forecasts for the coming autumn vary widely: Favorable scenarios assume that Omikron will be replaced by a weakened, more harmless virus variant.

However, it also seems possible that a further significant increase in infections can be expected with the colder season.

In order to be prepared for this, both vaccine manufacturers – Biontech/Pfizer as well as Moderna – are currently working on adapted vaccines against the now predominant omicron variant of the corona virus. Compared to this, the protection against infection of the originally developed vaccines was weaker, even if the protection against severe courses is still high.

The promise of mRNA technology is to be able to react quickly to such progressive changes in the pathogen with advanced vaccines.

The preliminary study results are encouraging: they indicate that the vaccine candidates can elicit clear immune responses against omicron variants. They should also be as well tolerated as the first generation of mRNA vaccines against Sars-CoV-2 was.

The new vaccine candidates under development differ from the “original vaccines” in many respects. A new mRNA sequence now serves as the basis for this vaccine. In both cases, it stores the information of the “omicron spike protein”.

Compared to the original (wild-type) coronavirus, this has accumulated a large number of mutations. The two vaccine developers are now taking these changes into account. A key advantage of mRNA technology: the manufacturing processes for both mRNA Covid vaccines remain very similar.

This should be reflected in comparable efficacy data, comparable tolerability and rapid availability – with the difference that these adapted vaccines now specifically prepare the immune system for the (mutated) omicron coronavirus.

The approach of the manufacturers is special: The further developed vaccines contain two blueprints of the spike protein – i.e. that of the original corona virus and that of the omicron variant. This is called a bivalent formulation because the vaccine should now contain two mRNA molecules.

It is hoped that this will result in the “broadest possible immune response” and thus the best possible prevention across different virus variants.

Both manufacturers recently presented initial data. However, these are not extensive “classic approval studies” in the true sense, in which the severity of infections or the quality of prevention is assessed in a very large number of participants by comparison with a large comparison group.

Rather, these are partly laboratory studies as well as observational studies on smaller patient collectives. Therefore, these results still leave some questions unanswered – such as how long such vaccination protection works or how many infections can be prevented.

Nevertheless, it is already evident that the adapted vaccines can generate robust immune responses against omicron and its subtypes. The (neutralizing) antibodies formed after a vaccination should also recognize the predominant BA.5 subtype in laboratory tests to a sufficient extent.

As with the first generation of Covid vaccines, tolerability also appears to be favorable.

This encouraging data is now being made available to regulatory authorities for review. However, it is not known when a decision on the approval status will ultimately be made.

While Biontech/Pfizer is “doubling down” – i.e. launching both a “purely omicron sequence” based vaccine and a combination vaccine – Moderna is focusing on the strategy of bivalent formulation with the vaccine candidate mRNA-1273.214.

According to the Federal Health Minister Karl Lauterbach (SPD), these vaccines could be available as early as autumn, provided the European Medicines Agency EMA and the Paul Ehrlich Institute (PEI) give the green light.

How high the need for adapted booster vaccinations will be cannot be reliably estimated at the present time. While in some countries of the European Union such as France or Austria there are already public discussions about fourth and even fifth vaccinations in order to be prepared in time for autumn, in Germany the Minister of Health Lauterbach in particular is campaigning for a timely second booster.

The Standing Vaccination Commission (Stiko) is more cautious and advises high-risk groups over the age of 70, immunocompromised people and employees in the health and care sector to be vaccinated a fourth time. There is therefore currently no recommendation for routine refresher training for all age groups.

It is unclear how further action will be taken. From a medical point of view, however, it cannot be ruled out that sooner or later another booster vaccination – also for younger people under 70 years of age – could become necessary in the foreseeable future.

This is because vaccination protection is known to slowly gradually decrease over the course of many months – regardless of whether immunity has been built up through infection or through vaccination.

The original of this article “New omicron boosters give hope: What you should know about vaccination” comes from NetDoktor.