How do virus mutations occur and how can they make the virus more dangerous?
Unlike bacteria, viruses do not survive on their own for long; They need cells that can smuggle their genetic information into them and their functions that can use their functions. In the case of SARS-CoV-2, cells in the human body act as hosts for viruses. And here they do what all life does: they multiply. The genome is also transcribed – and repeatedly small errors occur during that transcription. The resulting changes in genetic material are called mutations.
Most mutations are not noticeable and have no noticeable effect. But there are also mutations that have greater effects. Most of these mutations make the virus unable to survive. For example, making it more vulnerable to the body’s defense mechanisms or causing viruses to lose their ability to penetrate other cells. These newly created variables disappear quickly.
On the other hand, other mutations of the virus have advantages in terms of spread: they may be better able to escape immune cells in the human body or penetrate host cells more quickly.
The law of evolution also applies to viruses
Variables with this beneficial mutation are more likely to spread. This is where Darwin’s Law of Evolution, Survival of the Fittest, works. A mutation is just a random change. But with millions of viruses – and therefore millions of mutations – everything suddenly makes sense: continuous trial and error helps the virus adapt to changes in environmental conditions.
“It’s perfectly normal for corona viruses, like flu viruses, to mutate over and over again,” said Roman Faulville, chief physician and president of the Bundeswehr Institute of Microbiology in Munich. “Coronaviruses are kind of slow when it comes to mutation because they try to incorporate relatively few errors into their genome.” However, its mutation rate has been sufficient to produce new variants, especially in the past few months and weeks, which give viruses important advantages.
What types of viruses are known?
Several SARS-CoV-2 mutations are known, but three are currently the focus of attention.
The variant called B.1.1.7 was discovered for the first time in Great Britain. With it, several proteins present on the surface of the virus are altered, which facilitates the smuggling of genetic material into human cells. Virologist Professor Christian Drosten, from Charité, assumes that this variant is contagious between 22 and 35 percent. Currently, it is suspected that a greater proportion of those infected also have a severe course.
B.1.351 is the name of the second variant discovered for the first time in South Africa. The COVID-19 virus has devastated South Africa, especially in the country’s cramped cities, and it is now likely that a large part of the population is infected. Thus, a mutation – B.1.351 – was developed here, which may have the ability to weaken the effect of the antibody on those who have already recovered. This means: There are indications that a variant from South Africa may also affect people who were already sick.
The situation is similar to that of the third variant, it is called B.1.1.28 P.1 and was found mainly in Brazil in the city of Manaus. Here too, SARS-CoV-2 spread widely during the first wave of the first half of 2020. A recent study – controversial, but tends to be correct – confirmed that the population of Manaus is highly polluted: more than 70 percent of the population are infected Published in the journal Science According to already being infected with SARS-CoV-2. According to the WHO, this should have achieved herd immunity. Even more alarming is that B.1.1.28 P.1 has spread further. Experts suspect a change similar to that of B.1.351, with which the immune defense system is already growing to some extent.
Peak protein modification
All three variants have a specific change in the region of the common spiny protein. Using a peak protein, the virus can anchor itself to the surface of a human cell. “This area is especially important for the virus to penetrate human cells,” said Roman Fulville. “Mutations in this sensitive part of the virus can easily affect the characteristics of the infection.”
Jesse Bloom, an evolutionary biologist at Fred Hutchinson Cancer Research Center in Seattle, finds similar mutations to be of concern: “Each time mutations arise and spread independently, this is strong evidence that these mutations have a great evolutionary advantage ”.
Are these variants already common in Germany?
Lothar Wheeler, president of the Robert Koch Institute (RKI), confirmed on February 5, 2021, that “the three variables arrived in Germany”. So far, variant B.1.1.7, first discovered in Britain, appears to be the most common in this country. According to Wieler, about six percent of new infections are currently caused by B.1.1.7.
Accurate numbers can still be difficult to obtain. Because, in order to detect the mutation, a complete sequence of the virus’s genetic data is usually required. However, in the usual tests, individual factors that characterize the virus as a whole are taken into account.
The federal government is now working to increase virus genome sequences across the country. Since January 19, 2021, a new regulation requires laboratories and facilities that implement the SARS-CoV-2 sequence to send the corresponding data to the Robert Koch Institute. “With the help of sequence data, it is possible to detect the evolution of viruses and the occurrence of new variants early,” explains the Federal Ministry of Health. “The introduction of new variants from outside can also be detected instantly.” Laboratories and facilities are entitled to a € 220 fee for data transfer.
The Becker & Kollegen Laboratory in southern Germany is another faster way to detect mutations. This is where the PCR samples are tested as positive for a specific change called N501Y. It occurs in all three variants, but not in the wild type, which is known as the ancient generalized pathogen SARS-CoV-2. Result: since the beginning of the year it has been measured that the mutation rate in the Munich region has increased.
Do the new variables increase the risk of reinfection?
In experiments with blood from patients recovered from Covid 19, it was observed that the antibodies present in it often did not prevent the cells from being infected with the South African virus. Therefore, the researchers suspect that the new variants may lead to an increased risk of developing a second infection after Covid-19 disease has been overcome.
Will the vaccine also work against the modified virus?
To date, three vaccines have been approved in the European Union: one from BioNtech / Pfizer, the other from Moderna and the third from AstraZeneca in collaboration with the University of Oxford. Soon, the question arose as to whether these substances also protect against mutations of the Coronavirus. After all, mutations are found in the protein spike, of all places, which is one of the main points of attack of antibodies produced by vaccination.
There is evidence that vaccines are not really effective against mutations – particularly against variants detected in South Africa and Brazil – compared to the circulating wild type of the virus. However, preliminary studies also show that vaccines still have an effect, meaning they can also suppress the spread of mutations. Although they sometimes do not provide complete protection against infection by one of the variants, the cycle tends to be significantly milder than in unvaccinated people.
Could the virus mutate faster if the second vaccination delays the recommended date?
Virologist Friedman Weber, managing director of the Giessen University Institute of Virology, believes this is possible. After the first vaccination, you have half the immunity to the virus. Weber said: “The virus will be trained in the body’s immune response, which has been in its primitive form since the first vaccination.” “This can lead to so-called escape mutations in the virus in order to escape the body’s immune response.”
Can I protect myself especially from new variants?
The new variants are more infectious because they can penetrate cells in the human body more easily and / or more quickly.
But the path to the lungs has not changed. Therefore, it is still important to strictly follow the AHA + L recommendation: keep your distance, monitor hygiene, wear a face mask on a daily basis and ventilate regularly. And keep contact lenses to a minimum.
What is being done now against the new variants?
Experts try to contain the mutations at three levels.
First – try more: As explained above, the federal government is now promoting single-variable testing. RKI is also building a platform through which laboratories can easily report on existing mutations.
Second – Understand: Researchers from around the world are currently working to better understand the virus’s mutations. This also includes finding potential vulnerabilities. They then try to quickly adapt the RNA vaccines, in particular to the new mutations.
Third – Protection: Currently (as of February 5, 2021), the number of new infections every day at 12,000 is somewhat low compared to the past few weeks. However, there is a reluctance in political decision-making bodies to facilitate the blockade. Because protection against mutations, especially in the beginning, is critical to stop its spread. For this reason, the maintenance of restrictions on public life is being considered until the risk of spreading the infection decreases.
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