Science

The coronavirus variants – 12/29/2020 – Atila Iamarino

If viruses have a particular skill, it is variability. Since they are simpler than you and I, who have cells, the process of copying your genetic material is more flawed in reproduction than in ours. This creates more errors with each new virus particle produced.

And viruses with an RNA genome like the coronavirus, dengue virus and HIV are even more prone to failure when reproducing. Each virus-infected cell can produce thousands of virus particles, each with several variations. The variation is the rice and beans of evolution.

This can make all the difference between the outbreak and the spread of a disease. Many emerging diseases that have emerged in the past few decades are caused by viruses: Chikungunya, Zika, Sars, Covid-19, etc. This is in part because other mammalian viruses can change so quickly that, if we screw it up, adapt to the human host and circulate and cause epidemics. Hence, our invasion of wild environments where other mammals live with their viruses is worrying.

This rapid development and the leap to a new host explain Covid-19. The emergence and spread of the Sars-CoV-2 coronavirus in China was particularly surprising for the speed at which it could be transmitted between people. Other outbreaks like SARS or even Ebola in 2014 were halted before the viruses that caused them developed enough to be well transmitted between people.

At Sars-CoV-2 we are too late. By the time we became aware of it, it was already able to transmit well between humans, which indicates that it has either evolved into a host that happened to make the right adaptations for humans – and the pangolin is the largest Suspects – or circulated among people. for months until the right mutations accumulate and cause the outbreak in Wuhan. We don’t yet know which of the two scenarios occurred.

The speed at which viruses develop also disrupts our immunity. As the flu virus circulates around the world and infects people, it accumulates small changes. After a year or two it changes enough to escape our immune systems and infect us again. In the case of Sars-CoV-2, he has not yet lived together with immune individuals enough to observe this type of evolution. This can happen in the future. And the strategy we have to follow is the same as that of the flu: update the vaccines regularly and run new vaccination campaigns.

When countries analyze the genomes of the coronaviruses circulating in the pandemic, we also see new variants emerge. Evolution does not favor viruses that more or less kill their hosts. It favors viruses that are transmitted more heavily, regardless of what causes it in sick people. And all we know so far is that variant B.1.1.7 does just that. This variant, first discovered in the UK, appears so transmissible that it is quickly becoming more common than others in the region. However, the proportion of infected people who need to be hospitalized is the same.

This should follow the development in real time. Other infectious variants are likely to appear or already exist, but in regions where testing is not done as much as in English. This development happens because the virus can reproduce and last as long as we have cases.

Keeping a distance and wearing masks is an obstacle to any coronavirus, from traditional to new variants. The concern must be to contain them all.

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