A flu vaccine that lasts longer than a year and has a broad enough effect to be effective against several dangerous influenza strains at the same time is a goal that immunologists at the

Icahn School of Medicine at the Mount Sinai Clinic in New York is now a good deal closer.

Austrian-born Florian Krammer and his team have tested a potential candidate for such a “universal vaccine” on mice.

Result: Even a single dose and comparatively small amounts of the mRNA vaccine can apparently be sufficient to bring about broad influenza protection.

Joachim Müller-Jung

Editor in the feuilleton, responsible for the "Nature and Science" department.

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The vaccine used was produced using mRNA technology, which is widespread in Covid-19 vaccines: parts of the genetic information of the virus against which the vaccine is to be vaccinated are packaged as tiny, minimally modified and thus stabilized RNA snippets in chemically produced nanospheres and the injected into the muscles of experimental animals.

The advantage of this is that the genetic information can be adapted depending on which virus mutations are particularly widespread.

So far, the so-called hemagglutinin proteins located on the surface of the virus have been used primarily for flu vaccines.

However, the influenza virus changes particularly quickly at this point and, like the Sars-CoV-2 pathogen, puts vaccine manufacturers under considerable pressure to adapt.

That is why it has been necessary to vaccinate every year and adapt to the prevailing virus.

This is particularly problematic with influenza A viruses, which can repeatedly trigger severe outbreaks and thus pandemics in humans worldwide.

By combining parts of the virus, Krammer and his team have succeeded in improving the breadth of the effect and the potential duration of the effect in a subgroup of these viruses by combining the rapidly mutating surface antigens, such as the hemagglutinin glycoprotein, with virus components that are less variable combined in the RNA vaccine.

A total of four virus proteins were selected: the hemagglutinin stalk, the neuraminidase, which is also common on the surface, and the two proteins matrix-2 and nucleoprotein located within the virus.

According to the researcher's report in the "PNAS", the RNA prepared and introduced in this way triggered a broad immune response after the injection, which promises long-term protection and could also work against pathogens from other flu virus strains.

This is experimentally further than with previous broad-spectrum vaccines.

However, such prototypes of universal vaccines still have to prove themselves in extensive clinical trials with volunteers.