‘Likely to see several more variants before the virus reaches a state where it can’t mutate further’

“I anticipate that we are likely to see several more variants before the virus reaches a state where it cannot mutate further with an advantage. I do not know when this is going to happen… perhaps over the next 2-3 years,” Karim said in an email interview.

“The mutations are expected to take us progressively to each new variant being more efficient in transmission and less virulent clinically (A variant that makes people more sick is likely to suffer from less spread as people stay home with infection),” he said.

In a commentary on the Omicron variant in The Lancet journal that he had co-authored earlier this month, Professor Karim had written that vaccinated people were likely to face a much lower risk of severe disease from the Omicron infection. But he also says that there is a lot of uncertainty about the exact nature of this variant since the cumulative impact of all the mutations in Omicron is not fully understood.

“Although immunological and clinical data are not yet available to provide definitive evidence, we can extrapolate from what is known about the mutations of Omicron to provide preliminary indications on transmissibility, severity and immune escape. Omicron has some deletions and more than 30 mutations, several of which overlap with those in the Alpha, Beta, Gamma or Delta variants. These deletions and mutations are known to lead to increased transmissibility, higher viral binding affinity and higher antibody escape,” he said.

“But the effects of most of the remaining Omicron mutations are not known, resulting in a high level of uncertainty about how the full combination of deletions and mutations will affect viral behaviour and susceptibility to natural and vaccine mediated immunity,” he said.

“At this stage, the available anecdotal data from clinicians at the front lines in South Africa suggest that patients with Omicron are younger people with a clinical presentation similar to that of past variants. However this anecdotal information should be treated with caution given that severe Covid- 19 cases typically present several weeks after the initial symptoms associated with mild disease,” he said.

Omicron is now the dominant circulating variant not just in South Africa, where it was first discovered in the third week of November, but many other countries in Africa and Europe. One infected person in the UK has also died, though it is still not clear whether the infection with Omicron was incidental to, or the cause of, death.