Mutated coronavirus variant sparks concerns over vaccine efficacy

Australian scientists are monitoring a new coronavirus variant with a high rate of mutations that recently emerged in South Africa.

Doherty Centre for Applied Microbial Genomics medical director Ben Howden.

Australian scientists are monitoring a new coronavirus variant with a high rate of mutations that recently emerged in South Africa and has now been detected in a host of other countries.

The variant, dubbed C.1.2, has a high number of mutations in common with the Delta and Alpha variants, but virologists say it is too early to tell whether it will prove to be even more infectious.

South Africa’s National Institute for Communicable Diseases first described the variant in a scientific paper that reported C.1.2 had an “unusually high” ­mutation rate of 41.8 mutations per year, more than any variant of SARS-CoV-2 that has emerged so far.

The new variant accounts for only about 2 per cent of cases so far in South Africa, but has also been detected in China, the Democratic Republic of the Congo, Mauritius, England, New Zealand, Portugal and Switzerland.

It first emerged in South ­Africa in May.

Australia’s Communicable Diseases Genomics Network is monitoring the variant but says no cases have been imported into Australia so far.

Co-chair of the network Ben Howden, the medical director of the Doherty Centre for Applied Microbial Genomics, said about half of the mutations in the spike protein of the C.1.2 sequences had also been seen in other variants of concern. C.1.2 has not been declared a variant of concern by the World Health Organisation.

“We are keeping a very close eye on this variant,” Professor Howden said.

“There’s some ­degree of concern because it has a large number of mutations that have been found in other variants of concern.

“What we do know is that some of the mutations that have been detected in other lineages have been shown to be linked to higher transmission rates, possibly some reduced effects of the immune system against the virus and higher rates of attachment to human cells. So it’s got some ­mutations that have been characterised in other strains that do impact biological fitness, but we just don’t know in this particular lineage what all of those together ­really mean.”

University of Queensland ­virologist Ian Mackay agreed it was too early to tell whether the new variant would prove more ­infectious than Delta.

The mutations N440K and Y449H, which have been associated with immune escape from certain antibodies, have also been noticed in C.1.2 sequences.

“It does seem to have picked up a lot of mutations in a relatively short period of time,” Professor Mac­kay said. “That doesn’t necessarily mean anything or it could mean something important.

“It might be including changes that make it more transmissible or less transmissible, causing more disease or less disease, we really don’t know until we explore what that mix of mutations really does.

“If those mutations have an ­impact on the variant’s ability to escape immunity generated by vaccines, for example, or for any new drugs that are under way, that would be concerning.”

NICD scientists on Monday said C.1.2 was only “present at very low levels” and that it was too early to predict how it might evolve in coming months.

“At this stage we do not have experimental data to confirm how it reacts in terms of sensitivity to antibodies,” NICD researcher Penny Moore said during a virtual press briefing.

Additional reporting: AFP