Omicron XE and XD: health chiefs ‘continue to monitor’ recombinant Covid-19 variants
- Their spread, severity, impact on vaccine performance and risk of reinfection are being assessed, WHO says
- XE is 10 per cent more transmissible than ‘stealth Omicron’ BA.2 but XD is no more transmissible, according to WHO’s latest evidence
“Recombinants will emerge,” said Babatunde Olowokure, the WHO’s western Pacific emergency director. “[It] occurs when at least two different viral strains infect the same cell and exchange genes between them. Recombination is common among coronaviruses and is expected.
“We continue to monitor those and how they are developing and spreading, particularly in terms of whether they are more transmissible or not.”
The WHO was also assessing disease severity, impact on vaccine performance and risk of reinfection, he said on Thursday.
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The global health body said the recombinant variants it was tracking included the XD lineage – a combination of the Delta and Omicron variants – and the XE lineage, which is a hybrid of Omicron sublineages BA.1 and BA.2.
Early estimates suggest that XE is 10 per cent more transmissible than BA.2 – dubbed “stealth Omicron” – but that XD is no more transmissible than other circulating variants, according to the WHO’s weekly Covid-19 update, published on Tuesday.