Coronavirus: Is the 'Mu' variant deadlier than Delta? Decoding all known COVID-19 mutations circulating right now

Even as the Delta variant of coronavirus continues to rampantly spread and dominate across the world, newer worries have cropped up with the emergence of a variant which has come to be known as the 'Mu' variant, which, according to some medical experts, is quite concerning and fearsome. While it has been branded as a 'Variant of Interest' by the WHO, latest reports have said that the variant is making its presence felt internationally, and has spread to over 49 US states and 40 different countries worldwide. Traces of the same haven't been observed in India yet.

While we are yet to know exactly how deadly or fatal the Mu variant of coronavirus could be for the world, there are fears that we'll continue to see more mutations and variants come up in high contagion-fuelled risk areas and poor vaccination coverage, just in the way Delta variant has resulted in Delta Plus. Before Delta too, there were a number of COVID variants which were (and still, in many parts) deemed concerning. So which exactly is the most fearsome variant right now? Delta, Mu or a possibly more contagious one in the making? Let's discuss...

The Alpha variant (B.1.1.7) is the first identified COVID-19 variant, traced in the UK and later became a dominant threat in the US, until March 2021. The variant was said to be a threat as it has been clinically found to be over 50% more contagious than the original Wuhan-identified variant. Evidence also suggests that the variant caused more hospitalizations and deaths than before, and was one of the primary reasons as to why vaccines for mass immunization were expedited. However, the vaccines have been a saving grace, and it was established that both vaccines and special monoclonal antibodies could effectively neutralize and protect against this variant of concern.

The Beta variant of COVID (with mutations B.1.351, B.1.351.2, B.1.351.3) was first traced in the end of 2020 in South Africa, from whereon it continued to spread into parts of Europe and America. While the fast spread and heavy infectiousness of the variant made the WHO term it to be a VoC, it was found to cause a low percentage of infections, in comparison to other variants. Even so, with the risk of contagion, the Beta variant, too posed a threat to vaccine efficacy and immune protection. Not only was it seen to surpass natural antibodies (gained after infection), vaccine antibodies and immune defence, too, were found to be less effective in neutralizing the mutations. It has also been associated with causing more cases of reinfections and breakthrough cases than the original strain.

The Gamma variant, first identified in Japan is said to be the most dominantly spreading variant in Brazil, which became a major COVID hotbed. Holding mutations P.1, P.1.1, P.1.2, this variant, too has been found to have difficult mutations in its spike protein, which could escape neutralizing antibodies. Breakthrough cases were observed with the use of Cansino vaccine, pushed for use in Brazil and some other South American nations. However, some other vaccines, such as the mRNA vaccines have been established to be more capable of effective neutralization.

The Delta variant (B.1.617.2, AY.1, AY.2, AY.3), first identified in India is not just responsible for wreaking havoc and causing extremely high volume of cases during India's second wave, but it is also a dominant threat in many more countries now. The variant is also strongly contagious, said to be at least 60% more infectious than the original strain and previous concerning variants as well, since it is much more efficient in sticking to ACE2 receptor cells. Newer studies have also now established that the Delta variant can cause presymptomatic infections, lead to heavy vital organ involvement, cause vaguely different symptoms, and of course lead to more hospitalizations and mortality.

The Delta variant has actually further mutated to cause more sub-variants, such as the Delta Plus variant (which carries mutations from the Beta and Gamma variants). What also continues to make the Delta variant much more scathing and scary is its ability to render vaccines less effective and bring their efficacy down considerably. With almost all the vaccines, the Delta variant has been known to cause a 20-30% drop in efficacy. There have also been more reports of reinfections and breakthroughs with this. Therefore, tackling the Delta variant continues to be a top focus right now, as it can cause high-level damage.