SARS-CoV-2 Variants: An Update

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As the coronavirus pandemic continues, we anxiously listen to the latest updates about the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its variants. The better we understand them, the more equipped we are to protect ourselves and follow the necessary measures needed to halt the pandemic.

In a previous SCIplanet article, we stated the major variants circulating in April 2021: B.1.1.7, 501Y.V2, and P.1. These variants were subsequently named Alpha, Beta, and Gamma. The remaining letters of the Greek alphabet have been used to name emerging variants from Epsilon up to Mu.

Classification of SARS-CoV-2 variants

Since these variants are increasing in number, with some persisting and others disappearing, the World Health Organization (WHO) has grouped them into Variants of Interest (VOI), Variants of Concern (VOC), and Variants Being Monitored (VBM). VOC have one or more of these changes: increased transmissibility (contagiousness), change in disease presentation, or decreased effectiveness of public health measures against them (including medications and vaccines). These groups are continuously updated and a variant may move from the VOC group to the VBM group if its levels decrease in the population. The variants that are currently a cause for concern are Alpha, Beta, Gamma, and Delta, while the VOI are Mu and Lambda.

Why do new variants appear?

It is natural for any virus to develop mutations over time, which leads to the appearance of variants. The factors that have increased the appearance of new variants are increased social mixing, not following preventive measures—such as facemasks and hand-washing—and unequal distribution of vaccines worldwide.

Delta and Delta Plus

The Delta variant is considered the most contagious to-date. It was first detected in India, in October 2020. It has widespread in 6 continents and is the most common variant in the United States. According to the Centers for Disease Control and Prevention, this variant may be less affected by vaccines, is transmitted more easily, and may be less affected by some monoclonal antibody treatments. This is because it has certain mutations causing a change in the shape of the spike protein on the virus’s surface. This makes some antibodies unable to attach to it well enough, in addition to other changes that cause it to make stronger attachments to our body cells.

Delta Plus, or AY.4.2, is a sub-variant of the delta coronavirus with an additional mutation in the spike protein. AY.4.2 cases have increased in many areas since July 2021, and are currently being monitored to see if the variant is more contagious or if it will require different measures to handle than other variants.

Omicron

Omicron, the 15th letter of the Greek alphabet, is the name of the most recent SARS-CoV-2 variant of concern. It was reported in South Africa in November 2021 and has been detected in several countries worldwide. This variant has multiple mutations that may change how the virus behaves, and how we respond to it. What we do know from early research is that it seems to cause more reinfection than other variants. However, it is too early to confirm that this is correct. Otherwise, there is not enough information about any difference in the symptoms, transmissibility of the virus, or the effectiveness of vaccines against it. The WHO advises sticking to the same preventive measures taken against all variants, and the same treatment protocols until new information is available.

Prevention and treatment

Some laboratory studies show that the available vaccines may be less effective against the new variants, so updated versions of the vaccines are being studied. Luckily, most of the available vaccines are still effective against the Delta variant, such as Pfizer, Moderna, and Johnson & Johnson’s Janssen (J&J/Janssen) vaccines. Booster doses are also being considered for individuals at high risk, such as those who have lowered immunity that did not respond well enough to the first two doses of the vaccine.

Final thoughts

It is important at this stage to use all the available tools to protect ourselves by practicing physical distancing, frequent handwashing, wearing facemasks, and getting vaccinated. It is our joint efforts worldwide that can help us end this pandemic.

References

cdc.gov
hopkinsmedicine.org
nytimes.com
pubmed.ncbi.nlm.nih.gov
scmp.com
who.int (1)
who.int (2)
who.int
(3)

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