SARS-CoV-2 will always be – New Vaccines Needed – Medical Practice

Coronavirus does not get more harmful over time

At the start of the coronavirus pandemic, it was heard again and again that the virus might disappear in the summer. Unfortunately, this was not the case. On the contrary: the new pathogen continues to spread and, according to experts, has not become less harmful. Additionally, mutations continue to appear, which makes it imperative to develop new vaccines.

Global vaccinations against SARS-CoV-2 and COVID-19, caused by the pathogen, give hope. However, experts believe that we will have to live with the virus for a long time.

Coronavirus variants that have changed dramatically

She says in current research that Corona research faces a mystery Input From “scilog”, the journal of the Austrian Science Fund FWF (Scientific Research Promotion Fund).

It has been known since the start of the epidemic that SARS-CoV-2 will mutate over time. This behavior was expected by the professional scientist, and influenza viruses also behave in the same way. According to the information, there were an average of two spikes per month, until the end of 2020.

But then, suddenly, drastically-changed variants of the Coronavirus appeared that contained not only one or two new mutations, but even 30 mutations in one go – enough to reduce the effectiveness of certain vaccines and cause infection rates to spike.

So the question of how such mutations in the virus arise is more pressing than ever. It will now be answered by a group about Andreas Bergthaler as part of a research project.

Mutations are not just a flaw for a virus

“Coronaviruses are RNA viruses,” explains a virologist and immunologist at CeMM, the Research Center for Molecular Medicine of the Austrian Academy of Sciences. “You have a relatively error-prone copying mechanism by default,” says Bergthaler.

As explained in the article, RNA in living cells has the function of transferring the genetic information stored in the DNA to the ribosomes, where protein molecules are produced according to the blueprints they contain. This is where RNA viruses get involved in this process.

Since corona viruses contain the largest RNA genomes of all known viruses, they have developed their own correction mechanisms to reduce the error rate. “However, errors or mutations are not just a defect of the virus,” says Bergthaler.

On the contrary, such new mutations allow the virus to adapt to new conditions. If we compare the genomes of today’s virus with the reference sequence, that is, the genetic information from Wuhan 2019, we see that about one or two mutations have been accumulated every month, ”the expert explains.

The virus can mutate faster

But since the end of December 2020, researchers around the world have observed a new phenomenon. “We continue to find new variants that are more mutated, with up to 30 additional mutations simultaneously.”

We are talking about the British variant B 1.1.7 and the South African variant B 1.351. Coronavirus has found a way to mutate faster. It has not been clarified whether this was a coincidence or whether there was a common cause behind this development.

Researchers have two hypotheses for this. “One of the doubts is that there was an intermediate animal host and that these mutations have accumulated there, but there are not many indications of this,” says Bergthaler, who has been following the dynamics of the mutation of the Corona virus in Austria since the outbreak of the epidemic.

The second assumption is: “Viruses can replicate in infected individuals for a very long time without being controlled by the immune system.” The pathogen would have had enough time to accumulate many of the mutations. This may be the case, among other things, in people with weakened immune systems.

“In our opinion, this is still not sufficient to explain why so many mutations accumulate,” says the virologist. “This is one of the questions we want to clarify.”

Hundreds of virus genomes in an infected person

The aim of the new basic project, on the one hand, is to understand how mutations accumulate in one organism, and on the other hand, how many of these mutations are transmitted to another person through the “bottleneck” of infection.

The range of mutations in a single infected person is sometimes much higher than the range of viruses that actually transmit between humans. “Every person can have hundreds of virus genomes, with slight differences,” explains the project manager.

“It is important for us that we can also detect these low-frequency mutations. We are able to detect mutations that are only present in one of 100 genomes in a sample,” says Bergthaler.

Plus, the passage of time is quite interesting. “If certain people are sampled multiple times, it is possible to study how the mutation distribution changes,” the researcher says.

And you want to see how many new mutations cross the infection bottleneck. To do this, you need pairs of infected people who know who got infected first and who has the virus. It is difficult to obtain robust epidemiological data for this purpose. But if we are successful, it will be possible to investigate the number of mutant viruses that are transmitted to an infected person, “Bergthaler hopes.

Bioinformatics methods can also be used to count the number of viruses that have actually been transmitted between two people.

More contagious and dangerous

The researcher does not see that the coronavirus could become more contagious but is more harmful during the mutation process, as it is suspected in various places.

“Of course, in theory, it would be a good evolutionary strategy for the virus to be as infectious as possible and harm the host organism as little as possible, as is the case with some herpes viruses,” says the scientist, but points to the British alternative: “There is now good evidence for That this variant is more contagious and at the same time also leads to more severe courses and increased mortality. “

In addition, as vaccinations advance, the pressure of selection on the virus will be increased through vaccinations. Bergthaler hypothesizes that new mutations (“immune escape”) will emerge that could partially reduce the effect of current vaccines. It is crucial to understand the exact mechanisms.

The worst of the post-summer is over

The current research project has a duration of three years – a long period in light of the dynamically changing situation. But Bergthaler is confident. The expert believes that if dangerous new virus mutations do not appear, we will have a sufficient vaccination rate after the summer and the worst will be over.

The virus will still be around in three years, but hopefully we will have the second, third and fourth generation vaccines by that time and learn a lot about the basic mechanisms of Covid-19 diseases. This should make strict measures like lockdown a thing of the past, ”says Bergthaler. (AD)