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A highly regarded expert on global public health has said that the omicron COVID-19 variant is “growing very very fast” but we cannot say if it has outcompeted delta, because in the last month “there wasn’t that much delta around in South Africa”.
In an interview to The Wire, Professor Ashish Jha, who is the dean of Brown University’s School of Public Health in the US, addressed three critical questions which will determine how worrying omicron is. First, is it more transmissible? Second, will it lead to more serious disease and hospitalisation? Third, will it resist immunity from vaccination or previous infection?
Jha accepts that preliminary data suggests omicron could be more infectious than delta but also points out this is not a definitive finding, because most of the cases have come from one province of South Africa (Gauteng). Jha says there is no evidence that the disease omicron creates “will be just mild”. We need to wait for the second or even third week of infection to know for sure.
Speaking about transmissibility, Jha said he was “very worried”. Omicron could accelerate across the whole of South Africa. However, he felt it was by no means certain it will spread similarly in India. He cited two reasons for this: the high sero-positivity rate in India (68%) and the high level of at least one vaccination (84%).
About omicron’s possible ability to evade immunity, both from vaccination and previous infection, Jha said the laboratory tests, whose results should be known in a week or so, will give us a clearer answer but the variant’s mutations on the spike protein, particularly the receptor binding domain, suggest there could be some impact on vaccination efficacy.