WHO upgrades BA.2.86 to COVID-19 variant of interest as US proportions grow

genomic sequencing

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The World Health Organization (WHO) last week reclassified the Omicron BA.2.86 variant—and its offshoots, including JN.1—as a variant of interest as global proportions grow, including in the United States, where it now makes up about 9% of circulating viruses, the Centers for Disease Control and Prevention (CDC) said today.

Not as dramatic as Omicron-Delta jump

The WHO's Technical Advisory Group on SARS-CoV-2 Evolution had initially classified the highly mutated BA.2.86 subvariant as a variant under monitoring in the middle of August. At the end of October and into the first week of November, BA.2.86 and its related viruses made up 8.9% of global sequences, a substantial rise from early October, when it constituted only 1.8%, the WHO said in its latest risk assessment.

The immune escape potential for BA.2.86 will vary by country, based on other circulating variants, population immunity, and vaccine coverage, but it won't likely be as dramatic as when Omicron emerged in Delta's wake, the WHO said.

Studies on the blood of patients who had breakthrough Omicron infections, including XBB viruses, suggest robust neutralizing activity against BA.2.86, a promising sign that updated vaccines will provide added protection by expanding B-cell protection. The WHO added that T-cell memory is reported to be highly durable and cross-reactive to BA.2.86, hinting at sustained protection against severe disease.

Though BA.2.86 has the potential to cause surges in infections, there's no indication that the disease will be more severe than other variants. So far there is no sign of a change in clinical presentation, but the experts added that data are currently limited.

The public health risk is currently low, and the emergence of BA.2.86 isn't likely to increase the burden on national health systems, the advisers said.

CDC shares latest BA.2.86 assessment

The CDC said that, since it first weighed in on BA.2.86 in August, proportions have slowly grown and now account for 5% to 15% of circulating viruses, a percentage that will likely grow. In a separate assessment, however, the agency added that BA.2.86 and its relatives—including JN.1—don't appear to be driving increases in cases and hospitalizations.

JN.1 is still below the 1% threshold for the CDC to plot it on its projection graphs, so it is therefore included under the BA.2.86 umbrella.

The CDC said it agrees with the WHO's latest risk assessment that the public health risk is low compared to other circulating variants, based on limited available evidence.

Meanwhile, a few other variants show rising proportions, the CDC said today. They include HV.1, now at 31.7%, HK.3, JD.1.1, and JG.3.

Small increase in US severity markers

In its latest data updates today, which cover the week ending November 18, the CDC reported more rises in its severity indicators, with hospitalizations up 9.7% and deaths up 8.3%.

For hospitalizations, a limited number of counties are in the high category, most of them in the Midwest. For deaths, a few states had slightly elevated levels, including Colorado, Kansas, Missouri, and Ohio.

Early indicators declined or held mainly stable. Emergency department visits for COVID rose 1.8%, while test positivity declined 1.7% to a national level of 8.2%—higher in the Midwest and Mountain West than in other parts of the country. New Mexico has the highest emergency department visit level, which is only at the moderate category.

Latest global snapshot

In its latest monthly global COVID situation report, posted on November 24, the WHO said cases declined 13% over the past month, while deaths dropped 72%, though it urged caution in interpreting the trends, due to declines in testing and reporting. Test positivity held steady at 8%, with a small drop in early November.

There were no major case rises by WHO region, though the African and Eastern Mediterranean regions showed upward trends for deaths.

Of countries that regularly report hospital data, hospitalizations for COVID declined 12%, though intensive care unit admissions were up 26%.

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