Two new variants (called ‘Mu’ and ‘C.1.2’) of SARS-CoV-2, the virus that causes COVID-19, have been featured in news stories recently.
Dr Seshadri Vasan, CSIRO scientist and COVID-19 project leader, gives some insights into the significance of these variants.
“It is normal for a virus like SARS-CoV-2, to have picked up tens of thousands of mutations, so the fact these are new variants is not on its own something to panic about.
“So far, only four variants are of concern (Alpha, Beta, Gamma, Delta) and another five of interest (Eta, Iota, Kappa, Lambda, Mu) to the World Health Organization (WHO).
“The fifth and latest variant of interest declared by the WHO is Mu (B.1.621), which was first identified in Colombia. Another variant under investigation in South Africa is C.1.2.
“It is too early to tell if these variants will have a significant impact on the pandemic. It is worth noting that neither of these variants have been detected in Australia yet.
“These variants have key mutations (such as N501Y and E484K) which are already present in the Beta and Gamma variants, so we don’t expect virus binding to the human ACE2 receptor to be any more effective.
“There are other interesting mutations in the receptor binding domain (such as Y449H and R346K which are conservative changes), and in the N-terminal domain (such as C136F and Y144S), and these may affect immune response. However, this is yet to be confirmed through clinical or experimental observations.
“At this stage, both these variants are certainly of structural interest. Further research is ongoing on how they might affect how infectious the virus is, or whether they will impact existing COVID-19 vaccines and therapies.”