How much do you need to worry about coronavirus variants?Viralologist explains his concerns

(THE CONVERSATION) Spring is coming and there is a sense of relief in the air. After a year of blockade and social distance, more than 171 million COVID-19 vaccines have been administered in the United States, with approximately 19.4% of the population fully vaccinated. But there is something else in the air. It is a variant of the sinister SARS-CoV-2.

I am a virologist and a vaccine scholar. That is, we spend our days studying viruses and designing and testing vaccine strategies against viral diseases. For SARS-CoV-2, this task is more urgent. We humans are competing for immunity to this cage virus. The ability of this cage virus to mutate and adapt seems to be one step ahead of our ability to acquire herd immunity. Due to the emerging variants, it could be a race to wire.

Five notable variations

RNA viruses such as SARS-CoV-2 constantly mutate as they increase their own copy. Most of these mutations eventually go against the virus and are eliminated by natural selection.

But from time to time, they benefit mutated or so-called mutated viruses. One example is a mutation that improves the ability of the virus to attach more strongly to human cells, thereby enhancing viral replication. The other is a mutation that allows the virus to spread more easily from person to person, which makes it more contagious.

None of this is surprising for viruses that have newly arrived in human populations and are still adapting to humans as hosts. I don’t think of viruses, but they are dominated by the same evolutionary drive as all living things. The virus’s first job is to perpetuate itself.

These mutations resulted in several new SARS-CoV-2 mutants, causing outbreak clusters and, in some cases, worldwide spread. They are broadly categorized as variants of interests, concerns, or significant consequences.

There are currently five concerns in the United States. B.1.1.7 that occurred in the United Kingdom. B.1.351. , South African origin. P.1. First seen in Brazil; B.1.427 and B.1.429 both originate from California.

Each of these variants has several mutations, some of which are important mutations in important regions of the viral genome. Peplomers carry a number of these important mutations because they are required for the virus to attach to human cells. In addition, virus-neutralizing antibodies usually bind to peplomer proteins, making peplomer sequences or proteins an important component of the COVID-19 vaccine.

India and California recently detected “double mutation” variants that have not yet been classified but are of international interest. They have one significant mutation in the peplomer similar to that found in the Brazilian and South African variants, the other already found in the B.1.427 and B.1.429 California variants. .. As of today, no variants have been categorized as a significant result, but this can change as new variants emerge, and you can learn more about variants that are already in circulation.

More infections and worse illnesses

These variants are of concern for several reasons. First, the SARS-CoV-2 mutants of concern generally spread from person to person with at least 20% to 50% ease. This infects more people, spreads faster and more widely, and eventually becomes the predominant strain.

For example, the B.1.1.7 UK mutant, first detected in the United States in December 2020, is currently a circulating strain prevalent in the United States, accounting for an estimated 27.2% of all cases by mid-March. I am. Similarly, the P.1 variant, first detected by travelers from Brazil in January, is now causing havoc in Brazil, causing the collapse of the medical system and killing at least 60,000 people in March. I will.

Second, the SARS-CoV-2 mutants of concern can also lead to more serious illness and increased hospitalization and mortality. In other words, they may have increased pathogenicity. Indeed, recent studies in the United Kingdom suggest that the B.1.1.7 mutant causes more serious illness and mortality.

Another concern is that these new variants may escape immunity elicited by natural infections or current vaccination efforts. For example, antibodies from people who have recovered after infection or who have been vaccinated may not be able to bind efficiently to the new variant virus, resulting in reduced neutralization of that variant virus. This can lead to reinfection and reduce the effectiveness of current monoclonal antibody therapies and vaccines.

Researchers are investigating whether vaccines against these mutants will be less effective. Most vaccines appear to remain effective against British variants, but one recent study found that the AstraZeneca vaccine was mild to moderate COVID-19 for the B.1.351 South African variant. It has been shown to be ineffective in preventing.

Meanwhile, Pfizer recently released data from a subset of South African volunteers. This confirms the high efficacy of the mRNA vaccine against the B.1.351 mutant. Other promising news is that the T cell immune response evoked by natural SARS-CoV-2 infection or mRNA vaccination recognizes all three variants of the United Kingdom, South Africa, and Brazil. This suggests that the T cell response stimulated by vaccination or spontaneous infection provides some protection against such mutants, even when neutralizing antibody activity is reduced.

Be vigilant and get vaccinated

What does this mean? Current vaccines may not be able to prevent the mild symptomatological COVID-19 caused by these mutations, but they may prevent moderate to severe illnesses, especially hospitalization and death. That’s good news.

However, it is imperative to assume that current SARS-CoV-2 variants are likely to continue to evolve and adapt. A recent study of 77 epidemiologists from 28 countries found that the majority needed to renew their current vaccine within a year to better treat the new variant, and vaccination. We thought that low rates could promote the emergence of such variants.

What do we need to do? What we’ve done so far is to use masks, avoid poorly ventilated areas, practice social distance techniques, slow down transmissions, and avoid further waves caused by these new variants. You need to continue. In addition, as many people as possible should be vaccinated as soon as possible in order to reduce the number of cases and reduce the chances that the virus will generate new mutants and escape the mutants. And to do so, it is imperative that public health authorities, governments and non-governmental organizations work on vaccine hesitation and equity, both locally and globally.

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This article has been republished by The Conversation under a Creative Commons license. Read the original article here: https://theconversation.com/how-worried-should-you-be-about-coronavirus-variants-a-virologist-explains-his-concerns-158360..