A virologist from Monash University Malaysia has highlighted how the mutations of new COVID-19 virus variant Mu may mean people who are vaccinated are not as protected compared with other strains.
According to Dr Vinod Balasubramaniam from the Jeffrey Cheah school of medicine and health sciences, most mutations of the SARS-CoV-2 virus (which causes COVID-19) occur over time and have either little or no effect on the properties of the virus. But the new Mu (B.1.621) variant that has now been detected in 39 different countries may be more resistant to vaccines because it had a ‘constellation of mutations that indicate potential properties of immune escape’.
“Mu has a number of mutations that suggest it could be more resistant to vaccines,” Balasubramaniam said.
“As yet there’s only limited information on this, with a study from a lab in Rome showing that the Pfizer/BioNTech vaccine was less effective against Mu compared to other variants when tested in a lab-based experiment.”
Despite this, Balasubramaniam said that the study still regarded the protection that vaccines offered against Mu to be robust. He cited limited snapshots that researchers had into the behaviour of the variant – testing by the University of Miami in July which showed 10% of all sequenced samples were Mu; and reports in August that full vaccinated nursing home residents in Belgium had died from a Mu outbreak – describing them as ‘striking reports’ but that needed further examination.
“Really, we don’t yet know whether Mu’s mutations will translate into increased infection and disease,” Balasubramaniam said.
“The global prevalence of the Mu variant among sequenced COVID-19 cases is currently below 0.1%. But it has consistently increased in countries such as Colombia with 39% and Ecuador with a 13 per cent increase.”
Columbia is the first country where the earliest documented sample of Mu was obtained in January 2021.
Last month the World Health Organization (WHO) reclassified the COVID Mu variant as one of interest, with a growing number of cases recorded in South America. It is the fifth new ‘variant of interest (VOI) to be monitored by the international body since March 2021.
Balasubramaniam said that one mutation in the Mu variant — P681H — is potentially responsible for giving the virus faster transmission characteristics. A study investigating this feature was still in preprint stages, he said, meaning that the findings have not been formally reviewed by other scientists.
“We can’t be sure of P681H’s effects on the virus’s behaviour just yet,” he said.
Other mutations, E484K and K47N, have more concrete evidence of making the Mu variant more capable of evading coronavirus antibodies.
“These mutations also occur in the Beta variant, and so it’s possible that Mu might behave like Beta, which some vaccines are less effective against,” Balasubramaniam said.
The virologist added that other Mu variant mutations had unknown consequences which required further scientific analysis to understand pathogenicity, virulence and transmission. This included the R346K and Y144T Mu variant mutations.
“As scientists globally are looking in-depth at its pathogenicity, virulence and transmission, we will only get a clearer picture in the coming months,” Balasubramaniam said.
“In the case of the Mu variant, as explained before, it contains the recipe for disaster as an initial look at the viral genome suggests the possibility of immune evading capabilities similar to other variants of concern.”
More emerging variants of the COVID-19 virus were inevitable, Balasubramaniam said, describing it as a ‘numbers game’. Because of this, the only way to address the challenge was through global vaccination
“Every time the virus reproduces inside someone there’s a chance of it mutating and a new variant emerging. This is a numbers game. It’s a random process, a bit like rolling dice. The more you roll, the greater the chance of new variants appearing. It’s basically a ticking time bomb,” Balasubramaniam said.
“[Global vaccination] is the only way to sprint towards the finish line to have any protection against these emerging variants.”