Coronavirus mutations: Can people who have recovered or been vaccinated be infected again? | Science| In-depth reporting on science and technology | DW | 21.01.2021
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Coronavirus mutations: Can people who have recovered or been vaccinated be infected again?

The Brazilian COVID-19 variant is of particular concern. The immune response of vaccinated people and patients who have recovered from COVID-19 may not be sufficient to fend off the mutated virus.

Until now, no one had analyzed so precisely which strain of the coronavirus COVID-19 patients had contracted. It was only through intensified sequencing that some countries found out which particular variant was currently rampant in their countries: the British variant or the South African variant, for example. The respective countries are not to blame in any way. They have only examined the virus particularly intensively and were the first to notice the mutations.

Intensified sequencing has revealed that the B.1.1.7 variant, which first spread in the UK and then in Denmark last December, is spreading up to 70% faster. It has since been detected in many other countriesincluding Germany.  

Mutations are nothing unusual in viruses.  On average, there are two new variants every month. However, in the case of the British virus variant, which has now been fully decoded, 17 gene changes have already been identified, which even astonishes virologists - according to an article in the journal JAMA.  Three mutations are being watched particularly closely: N501Y, which possibly improves the binding of the virus to human cells, as well as the deletion of positions 69 and 70, and the mutation P681H. 

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Why do viruses mutate?

Mutations cause more rapid spread

The reason for the rapid spread could be a slight change in a spike protein site on the virus surface. These copying errors allow the mutated virus to replicate, transmit or escape the immune system more easily than the original coronavirus. Therefore there is a high likelihood that this more effective virus will become established as the predominant variant locally or regionally.

However, the rapid spread does not mean, for example, that the British variant is also responsible for more severe COVID-19 courses or a higher mortality rate. So far, there is no evidence of this. For the infected person, it is therefore irrelevant which variant they have contracted. The mutation has no influence on the course of the disease. 

Symbolic picture: DNA with a pipette and a petri dishPetrischale

Only through comprehensive sequencing will the new viral mutations be discovered

However, the rapid spread of the disease can lead to the collapse of overburdened healthcare systems in some countries. In many places, there are shortages of hospital beds, ventilators, intensive care units and staff.

Variant B.1.351., which has been rampant in South Africa  since last August, is similar to the British variant and is also blamed for the most rapid increase in the number of cases in South Africa. It carries other spike protein mutations in addition to N501Y, including a mutation called E484K that has a negative effect on antibody binding and corona neutralization. 

Recovered and vaccinated people could be infected again

Also of concern is variant P.1, identified only recently in Brazil,  which has 17 mutations, some also in the spike protein. The variant carries the N501Y mutation discovered in the British and South African variants and the E484K mutation so far detected only in the South African variant. 

People lining up at an oxygen dispensing station in Manaus to get oxygen pressure tanks filled

Although much of the population in Manaus had already survived COVID-19, the infections returned.

This Brazilian variant first appeared in Manaus, the capital of the state of Amazonas, where three quarters of the population were infected with the novel coronavirus last year. That should have led to some basic immunization  in a large part of the population, but infection numbers there have recently been rapidly rising again. 

This could mean that the body's immune response in people who have recovered from COVID-19 or those who have been vaccinated is not sufficient, because the new variant P.1 escapes the immune response. In this situation, some antibodies can no longer bind and neutralize the virus — it partially escapes the immune response. In other words, even recovered and vaccinated individuals could become infected. 

It is unclear whether a mutant variant of the virus is responsible for the death of a 73-year-old man from southern Germany. He died in late December after a second COVID-19 infection led to pneumonia and multiple organ failure. It is only the third known death worldwide from reinfection. It is possible that he did not develop strong immunity from his initial infection. It is now being investigated if he was infected the second time with one of the new virus variants. 

 A woman in South Africa wearing a mask and a face shield

In South Africa, the E484K mutation was rampant and had a negative effect on antibody binding.

Many local mutations

The more intensively the respective corona cases are sequenced, the more mutations are likely to be discovered in the near future. However, these do not always have to be serious.

The virus variant recently detected in a corona outbreak at a  Garmisch-Partenkirchen hospital in Germany's state of Bavaria is said to be only a partial mutation, meaning it is not the British or South African variant. To clarify the matter, the relevant samples are currently being analyzed at the Charité hospital in Berlin.

And the virus variant that has surfaced in the greater Los Angeles area is apparently a strain called L452R,  which was first identified in Denmark in March last year. But even there, there is concern that the vaccines could lose their effectiveness.

Do the mutations endanger the effectiveness of the vaccines?

So far, whether the developed mRNA vaccines also work with these additional mutations, and if so, how well, has not been conclusively investigated. If part of the distinctive spines, which are important for recognizing the virus, changes, the antibodies produced by the body may be less able to recognize and neutralize the coronavirus. Vaccine protection would then lose effectiveness. 

Workers in protective clothing at a graveyard in Manaus/Brazil

In the Brazilian state of Amazonas alone, more than 223,000 corona cases were registered last year

As things stand, the vaccines from BioNTech/Pfizer and Moderna are also effective against the British virus variant B.1.1.7. because these mRNA vaccines dock precisely at the affected spike protein.

The extent to which the vaccines already available can also cope with the other mutations that have become known and with further variants must be shown by further investigations.

If at some point the virus mutates to such an extent that the immune response triggered by the vaccination can no longer neutralize it, then the vaccines would have to be adapted. 

Such an update is not very difficult with the mRNA vaccines, according to BioNTech-Pfizer. The genetic code of the virus contained in the vaccine can be changed relatively easily within a few weeks.

But testing and approval, as well as production and distribution of the adapted vaccine, are known to take time — and already many vaccination centers are eagerly awaiting the currently valid vaccines. 

This article has been updated since its original publication

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