With spray against corona – will we soon vaccinate with Covid-19 via the nose? – Knowledge


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A new vaccine that guarantees better immunity and is easily administered through the nose. Two Swiss research groups are pursuing this vision. The researchers from Bern are now publishing new data.

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A quick spray in the nose and the risk of infection with Covid-19 is averted. This is how Volker Thiel imagines the use of his Covid vaccine in the future. Since the beginning of the pandemic, he and his team have been researching a vaccination with weakened corona viruses: “We are confident because we have very good preclinical data.”

According to Thiel, these data suggest that his vaccination offers better protection against infection and disease, has fewer side effects and is easier to administer than previous Covid vaccines. New data on animal testing was released today.

Volker Thiel

Professor of Virology at the University of Bern


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Thiel is considered one of the leading coronavirus researchers and heads the Virology department at the Institute of Virology and Immunology (IVI). As a professor of virology at the University of Bern, he has been researching viruses for years, including the pathogens that cause the dangerous respiratory diseases Sars and Mers.

However, his research results have a big “but” because there is still a long way to go before Thiel’s goals become reality. The data are based on animal studies and have not yet been confirmed in humans. The validity is therefore limited. In addition, it is still a preprint, which must now be checked independently.

weakened viruses

Nevertheless, his results are exciting, because Thiel works with the classic vaccination principle of weakened viruses instead of mRNA technologies. A short infection takes place, which is stopped in time.

Old principle – new method


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Attenuated viruses have a long tradition in vaccine development. However, the method that Thiel’s research team used to weaken the virus is new. “So far there is no approved vaccine whose viruses have been weakened with these so-called “one-to-stop codon modifications”,” says Thiel.

In order to multiply, viruses exploit the cellular machinery of the infected host cell. As soon as the virus has entered the cell, it releases its genetic material. This viral genome is read by the cell’s own machinery and serves as a blueprint for the various virus components. The host cell produces these viral components, which then assemble and release new viruses. The virus multiplies.

In order to weaken the natural Sars-CoV-2 virus, the Bern research group modified its genetic make-up. And in such a way that the probability of premature stop codons increases. Stop codons are sequences of bases that mark the end of the blueprint for a viral protein. Similar to how a period marks the end of a sentence. If such a premature stop codon occurs, protein synthesis breaks off prematurely: faulty virus components develop. This reduces viral fitness and pathogenicity. This means that the virus is less harmful than the natural one. The virus has weakened.

The hamsters and mice examined in the study were able to react more quickly to the viruses and were better protected against disease. They have developed a so-called “full protection” that protects better against infections, “And we can prove that very well in animal experiments,” says Thiel.

The way over the nose

Another advantage: administration to the nasal mucosa, where the virus enters. After a vaccination, the corona viruses can be warded off directly at the entrance door.

state of research


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Around the world, around a hundred research groups are working on various approaches to nasal Covid vaccines. Among them is another team from Switzerland led by virologist Thomas Klimkait from the University of Basel. The Basel group is at a similar point as the researchers in Bern and hopes to be able to start the clinical phase with their approach of genetically modified whole viruses soon.

The US company Codagenix is ​​one of the most advanced in terms of weakened corona viruses. Your vaccine is currently being tested in a clinical trial with the WHO in various countries, currently in Colombia.

But not everyone places equal hopes in the nasal approach. The US immunologist Paul Offit puts it into perspective: “It is unlikely that the nasal vaccines offer better protection for a longer period of time.” Offit fears that the generated antibodies are too short-lived.

However, Volker Thiel sees potential in the “often underestimated memory and T-cells”, which in his approach should protect against illness for longer. And: “The vaccine can be refreshed seasonally, just like the flu vaccination.”

Why a new vaccine?

At least the existing mRNA vaccines protect against serious illness and death and the acute phase of the pandemic is over. But there are people who could be better protected. “Especially those population groups that may have to reckon with severe courses and have other diseases, including older people,” says Thiel. It is therefore important to test such concepts and to further develop vaccines, also with regard to upcoming pandemics.

However, one thing is clear: It will still be years before the vaccine comes onto the market, because first there are demanding and lengthy tests on humans. Volker Thiel finds this appropriate, there is no longer a need for this increased time pressure as at the beginning of the pandemic.

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