Coronavirus variants don’t have to be scary

The news about emerging variants of the coronavirus may seem terrifying to an audience unaccustomed to genomic lingo. But viruses frequently mutate, both in infected individuals and as they move from person to person. This is why it is important to remember this adage (modified)– All variants are innocent until proven guilty.

The coronavirus responsible for the pandemic, SARS-CoV-2, has nearly 30,000 bases, or nucleotides. As the virus evolves and spreads from host to host, some of these bases change. If only 20 bases changed, that would produce more than a trillion possible different variants of the strain responsible for the first outbreak. Of the 137 million confirmed cases of Covid-19 worldwide, at least one million have already sequenced the virus. And out of that million sequences, scientists have only been concerned with a handful of variations, because they’re more infectious, cause more serious disease, or partially escape our immune response … or all of that together.

In other words: Hundreds of thousands of sequences have not been associated with substantial changes in virus behavior. These changes can help scientists track how and where the virus is spreading, but other than that they are of little medical significance.

So far it has been shown that five variants are guilty, as evidenced by the new designation of the Centers for Disease Control and Prevention (CDC): “worrisome variants“. These are B.1.1.7 (first identified in Great Britain), B.1.351 (first found in South Africa), P.1 (identified in Brazil) and two other variants found in California and New York. Each has less than two dozen notable mutations, many of which are in the spike protein of the virus, which is what binds to our cells and is the primary target of vaccines. Some mutations improve the virus’s ability to bind to cells that line our upper respiratory tract, while others interfere with our body’s ability to generate a full immune response.

Fundamentally, the number of mutations is not directly correlated with any notable change in the infectivity of the virus. For example, a variant in Angola was recently found to have the highest number of mutations to date, but there is no clear evidence that it causes more disease. It takes considerable work, laboratory studies, and a large number of people to determine whether a variant can cause an increase in cases, hospitalizations, deaths, and re-infections.

Vaccines administered in the United States were developed before new variants appeared. However, so far they seem to be effective. The Moderna and Pfizer vaccines, which use a technology called mRNA, have been shown in lab studies to be effective with each of the major variants. Even when certain variations make vaccination ineffective, the coronavirus mRNA vaccines currently in use are so good that they are unlikely to be significantly affected in terms of efficacy.

For its part, the limited amount of evidence available for the Johnson & Johnson, AstraZeneca and Novavax vaccines suggests that they remain effective against the newer variants. So far, the variant B.1.351 seems to be the one with the best ability to evade vaccines, although studies show that all injections prevent major illnesses.

In the United States, the variant B.1.1.7 he became the most dominant. Think of it like a widespread version of the virus, able to outperform variants that cannot transmit as effectively. We know from Britain, where this variant is responsible for almost 100% of infections, that vaccines have been very effective in reducing cases, hospitalizations and deaths. Israel’s reports, which vaccinated its population faster than any other country, showed that the efficacy of mRNA vaccines was not reduced by the three most common “variants of concern”.

The United States is experiencing a fourth wave of Covid-19, the most dramatic in Michigan, where over the past two weeks the number of new cases has increased by 60% and deaths and hospitalizations have more than doubled. Vaccines were not available in previous waves, but now, with the current influx of vaccines, it is possible to stop the increase in cases as soon as they appear. Unfortunately, the United States is strictly committed to allocating vaccines only on the basis of population rates, instead of using a specific approach to control hot spots like Michigan. This approach goes against what has worked in other countries like Israel and Britain.

This approach is contrary to what has worked in Israel, Britain and other countries.

The main variants pose a challenge, but the extraordinary effectiveness of our vaccines will eventually cancel them out. This is in part because vaccines induce a much larger and more potent immune response to the coronavirus than humans themselves. But it is essential that we contain the virus so that it can no longer evolve and, in theory, avoid our vaccines.

Vaccines are a vital tool, but masks and distancing also work very well against the newer variants. Combining these mitigation strategies with vaccination is the fastest way out of the pandemic.

* Dr Topol is Professor of Molecular Medicine at the Scripps Research Institute and served on the Advisory Board of the Covid Tracking Project

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