The Perfect Enemy | Global COVID activity mixed as WHO updates variant tracking
February 26, 2024

Global COVID activity mixed as WHO updates variant tracking

The WHO’s new variant tracking system better distinguishes Omicron sublineages and outlines when new SARS-CoV-2 changes pose major public health threats.

COVID-19 cases and deaths continue downward trends, but with some regional differences, the World Health Organization (WHO) said today in its latest weekly update. Also, the group unveiled changes in its variant tracking system, which better defines sublineage circulation and identifies that ones that could prompt major public health actions.

Some nations see rises as XBB.1.5 rates climb

Over the past 28 days, COVID-19 cases declined 40% and deaths dropped 57% compared to the last 4-week period, the WHO said.

Cases were up modestly, however, in Europe, the Middle East, and India. In Europe, Russia, Germany, and Austria were among the countries reporting rising cases, while rises in the Mideast were partly driven by activity in Iran, and to a lesser extent, the United Arab Emirates. And India reported a spike in cases.

Regarding variant activity, the WHO said proportions of XBB and its related sublineages, including XBB.1.5, continue to rise and are now dominant in all regions except for the Western Pacific. It said there are 25 descendent XBB lineages, 3 of which show a growth advantage: XBB.1.5, XBB.1.9 and XBB.1.9.1.

Updated variant tracking

In a separate statement today, the WHO said it has tweaked its variant reporting to better reflect the current landscape, independently evaluate the Omicron sublineages that are circulating, and clarify new variants when needed.

It said Omicron viruses continue to evolve, expanding into multiple sublineages and accounting for 98% of sequences since February 2022. Though new SARS-CoV-2 variants will likely stem from Omicron, the WHO emphasized that the emergence of new variants from earlier variants of concern or completely new variants are still possible.

The group said the way it had been classifying Omicron variants didn’t clearly distinguish among them. So, as of yesterday, it will consider Omicron sublineages independently as variants under monitoring (VUM), variants of interest (VOI), or variants of concern (VOC). The Omicron parent lineage is classified as a VOC, but XBB.1.5 is classified as a VOI.

WHO emphasizes that these changes do not imply that the circulation of Omicron viruses no longer pose a threat to public health.

“WHO emphasizes that these changes do not imply that the circulation of Omicron viruses no longer pose a threat to public health,” it said. “Rather, the changes have been made in order to better identify additional or new threats over and above those posed by the current Omicron viruses in circulation.”

Also, the WHO said it is updating is definitions of VOCs and VOIs to make the one for VOC more specific to cover major SARS-CoV-2 evolutionary steps that require major public health interventions. It said going forward that Greek labels will be assigned only for VOCs.