COVID Mu Variant Hits Rhode Island -- It May Be Resistant to Existing Vaccines

COVID Mu Variant Hits Rhode Island -- It May Be Resistant to Existing Vaccines

There is a new SARS-CoV-2 virus variant knocking on our door: Mu.

Variants of the SARS-CoV-2 virus continue to emerge and are getting better at evading our defenses. This is the natural process of evolution. Alpha was more contagious than the original strain, and Delta is more contagious than Alpha. Literally, thousands of variants have been identified since the start of the pandemic. The total number of possible mutations is astronomically high, and the number of potential variants is impossible to predict.

Evolution drives the virus to continue to mutate in ways that increase its chances for survival. The ways it can do this are generally by becoming more contagious (such as reproducing faster and making more copies of itself more quickly), or by evading our defense mechanisms such as being less susceptible to neutralization by the antibodies generated by vaccines, or suppressing our own natural immune response.

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A common way the SARS-CoV-2 virus mutates is in the region of its “spike protein”. The spike is both the part of the virus that it uses to attach and insert itself into our cells, and also the region targeted by vaccine antibodies. Changes to the spike protein can make a variant both more infectious by being able to enter our cells more easily, and more resistant to vaccines because antibodies cannot bind as tightly to the mutated spike.

The Delta variant does all of these things, which makes it especially dangerous and why it has quickly become the predominant strain around the world and in this country, accounting for 99% of infections.

The new Mu variant, also called B.1.621, was first identified in Colombia. It has now been found in 42 countries around the world. In the U.S. it has been found in 47 states with a total of 1,672 cases - including 8 cases in Rhode Island, 24 in Massachusetts, and 50 in Connecticut.

Mu is potentially dangerous because it has a total of 17 mutations shared with other variants which are known to be associated with increased transmissibility, escape from antibodies generated by COVID vaccines, and suppression of the human immune system.

Information on the Mu variant is still developing, but initial studies suggest that the multiple spike mutations may indeed make it more resistant to antibodies from the current vaccines. 

The transmissibility of Mu is not yet known. However, it’s concerning because in Columbia where it was first identified, Mu cases increased rapidly and now represent 31% of infections. 9% of cases in Miami-Dade county in Florida are reported to be the Mu variant, and 3% yet another new variant, Lambda.

In Belgium, 21 residents of a nursing home recently became infected and 7 died of Mu variant infection – despite all of them being vaccinated.

The World Health Organization and the European Center for Disease Control and Prevention have both designated Mu as a Variant Of Interest.

Since it’s not yet known how contagious Mu is, it’s also unknown if it will displace the Delta variant or not. Resistance to vaccines alone does not guarantee that a variant will become predominant – a key factor is transmissibility. Other variants such as such as Gamma (also known as P.1, first identified in Brazil) are also resistant to vaccine antibodies, but because they are less contagious than Delta have not displaced it.

There is worry about the Mu variant because it possesses a combination of mutations from other variants that have been shown to both be highly transmissible such as Beta and Delta, and also escape vaccine antibodies. It must be watched closely, because if it turns out to be as or more contagious than the Delta variant, we may have an even more serious health problem than the Delta variant coming our way.

The SARS-CoV-2 virus will continue to mutate, and it is certain that new variants will ultimately emerge that completely defeat currently available vaccines. The more people that get infected, the more variants will be created, since each infected person’s body is essentially a mutation factory. We need to keep a close eye on the Mu variant, as well as the Lambda variant on the horizon.

Additional booster shots and new vaccine formulations will be needed on a regular basis for the foreseeable future as new variants continue to evolve. This is why Israel is already planning to give a fourth vaccine dose to its people at a time when health officials in the U.S. are mired in debate over the need and timing of a potential third vaccine dose.

"Given that that the virus is here and will continue to be here, we also need to prepare for a fourth injection. This is our life from now on, in waves”, said Dr. Salman Zarka, Israel’s coronavirus czar. 

Nick Landekic is a retired scientist and biotechnology executive with over 35 years of experience in the pharmaceutical industry.