New Variants of SARS-CoV-2: Delta, Delta Plus, and Mu
Since the beginning of the pandemic, the virus has changed through mutations to adapt to various human populations and environments. When a virus has one or more new mutations, it is called a variant of the original virus. These continuous mutations of SARS-CoV-2 resulted in several variants with differing characteristics. Some variants seem to spread more easily and rapidly than other variants, which may increase the number of cases. Some variants also seem to cause more severe cases compared to others, leading to higher risks of death.
In addition to the spread of the disease, variants may have an impact on the effectiveness of vaccines and antiviral treatments. Scientists continue to analyze the effectiveness of monoclonal antibody treatments, natural immunity, and the antibodies generated by a COVID-19 vaccine against emerging variants of SARS-CoV-2. So far, officials have recognized four variants of SARS-CoV-2 as significant: Alpha, Beta, Gamma. Recently, two variants are added to the list: Delta, Delta Plus, and Mu. In this article, we examine the origins of the variants and how they impact the world.
What Is The Delta Variant?
First identified in India in December 2020, the Delta variant evidently spreads much faster and easier than the previous variants. Research shows that the virus went through certain changes. These changes create the variant bind and enter human cells with much more amount of effectiveness than its previous forms. In fact, some analyses suggest that it may be twice as contagious as previous variants. Some research even shows that individuals infected with the Delta variant seem to have viral loads 1,000 times greater than those observed with previous variants.
In addition, scientists found some evidence to suggest that the Delta variant may cause more severe cases than previous variants in unvaccinated people. Researchers suggest that this variant might reduce the effectiveness of some monoclonal antibody treatments. It may have a bad impact on the effectiveness of the antibodies generated by a COVID-19 vaccine. Altogether, the Delta variant has quickly spread to more than 170 countries around the globe since its identification. Today, Delta is one of the most predominant variants of SARS-CoV-2 worldwide.
The Delta variant is evidently much more contagious than the previous forms of SARS-CoV-2. However, current research has not detected significant immunity against vaccination. In other words, vaccination remains an effective method against the Delta variant. Vaccination proves to reduce the number of cases in total. Besides, fully vaccinated individuals have a much lower risk of developing severe symptoms and death. Much like patients infected with the previous variants of the virus, the highest risk of transmission, severe illness, and mortality is still among unvaccinated people. Still, some researchers argued that while existing vaccines prove to be effective especially in preventing severe disease, discovering delta-specific vaccines with higher levels of antibodies could also be helpful against the high viral load of the Delta variant.
What Is The Delta Plus Variant?
The Delta Plus is an altered version of the Delta variant. Like the Delta variant, the experts believed that the Delta Plus to be originated in India. It contains an extra mutation in the spike protein. This mutation makes it possible to create a stronger link between the virus and human cells. Despite this, officials note that it might not be an immediate concern as the proportion of people infected with the Delta Plus variant is relatively low.
In June 2021, the health ministry of India reported research showing that the new variant binds more easily to lung cells. In addition, the Delta Plus variant spreads more easily. This report showed that the variant might be more immune to a type of treatment called monoclonal antibody therapy. However, the initial research on the variant suggests that while this new mutation appears to cause a modest reduction in the impact of the vaccine, it does not give the virus a significant additional advantage against the protection provided by vaccination. Altogether, Delta Plus is found in relatively high numbers of cases. Contrary to the initial studies suggest that its additional mutation is unlikely to have a significant impact.
What Is The Mu Variant?
Mu variant was first reported in January 2021 in Colombia. It is not widely studied, and much of the research is under development. Therefore, we have limited knowledge about the Mu variant. This variant has been reported in more than 40 countries around the globe. However, it caused major outbreaks mainly in South American countries such as Colombia and Ecuador, along with some parts of Europe.
Current research suggests that the Mu variant has mutations shared within the Alpha, Beta, and Gamma variants. Moreover, the Mu variants have a mutation as same as in the Delta variant. Although the research on the subject is inconclusive, initial research points out that the Mu variant might have higher resistance against vaccines and natural immunity than previous variants. Some researchers have pointed out that the Mu variant carries the same spike mutation as the Beta variant. The mutation is responsible for reduced vaccine response. Similarly, although antibodies remain effective, the Mu variant was relatively more resistant against vaccine-elicited antibodies than the other variants. The extent of this resistance is not yet clear, still, this could mean that vaccinated individuals and the people who previously had COVID might have less protection against this variant compared with others.
Comparison of The Variants
On the other hand, while the research on the variant is scarce, it seems that the Mu variant does not spread as rapidly and easily as the Delta variant. Consequently, officials have observed that while in certain places such as Colombia and Ecuador, the proportion of cases infected with the Mu variant may increase, in other places, its proportion decreases, and the Delta variant quickly dominates the cases. In other words, while the Mu variant might be the most immune variant so far. The Delta variant appears to outcompete the Mu variant along with the previous variants due to its superior transmissibility. Although it might have features that elevate its resistance against vaccines and natural immunity, some researchers suggest that the fact that it appears to be much less contagious than the Delta variant could imply that the Mu variant will gradually vanish.