KUALA LUMPUR, April 18 – Omicron subvariants BA.4 and BA.5, which have been detected in Southern Africa and some European countries, do not appear to be more severe or transmissible than the original Omicron mutation so far, though this may change as more cases are detected.
“There are less than 200 sequences available so far and we expect this to change… We are tracking (the virus) very closely to see if there is any uptick in case detection, but (so far) we haven’t seen any change in epidemiology or severity,” said the World Health Organization’s (WHO) lead epidemiologist Maria Van Kerkhove in a statement last Wednesday.
In a separate WHO briefing, Van Kerkhove emphasised the need to maintain robust genome surveillance systems that will allow countries to track and analyse the two subvariants and earlier versions of Omicron.
“It is still early days. What we have to make sure is that we continue to have the ability to track, the ability to share and the ability to analyse so that we can answer questions like this,” Van Kerkhove was quoted as saying during the WHO briefing last week.
The latest sub-lineages BA.4 and BA.5 have been reported in a number of countries, including Botswana, South Africa, Germany, Belgium, Denmark, the United Kingdom, and most recently in Australia’s wastewater.
The WHO said it was tracking a few dozen cases of BA.4 and BA.5, in addition to earlier Omicron variants such as BA.1, BA.2, BA.3 and BA.1.1.
WHO’s director of emergencies Dr Michael Ryan warned that as the virus continues to evolve, the world “cannot simply afford to lose sight of it”.
“It would be very short-sighted at this point to assume that lower numbers of cases mean absolute lower risks. We are pleased to see deaths dropping but this virus has surprised us before, it has caught us off guard before.
“We need to do our jobs and track this virus the best we can, while people go back to live their lives as normally as possible,” Ryan said.
WHO’s lead scientist Soumiya Swaminathan, warned that sublineages and recombinants will continue to appear, and the world must continue investing in improved tools such as new vaccines.
“We have to be prepared for the possibility that this virus can change so much that it might be able to evade existing immunity,” she said.