WHO says Kraken ‘misses’ indicator for severe disease, NICD believes it could become dominant strain in SA

A preliminary risk assessment done by the World Health Organization (WHO) has found that the Kraken subvariant of Omicron (XBB.1.5) does not have a specific genetic mutation associated with variants that cause severe disease.

“Severity assessments are ongoing. XBB.1.5 does not carry any mutation known to be associated with potential change in severity (such as S:P681R),” the report reads.

The WHO, however, called on more countries to do a rapid assessment of the situation, saying there is currently very little data available. According to the risk assessment, the subvariant is now found in 38 countries. 

“Based on its genetic characteristics and early growth rate estimates, XBB.1.5 may contribute to increases in case incidence. To date, the overall confidence in the assessment is low, as growth advantage estimates are only from one country, the United States of America,” the report reads.

The WHO called for more studies to assess the potential of XBB.1.5 to escape either vaccine- or infection-acquired immunity, and also on whether the subvariant caused more severe disease.

The European Centre for Disease Control (ECDC) this week issued a statement saying it looks like XBB.1.5 will have a growth advantage over the other subvariants in circulation, but such estimates are “associated with significant uncertainty”.