The World Health Organization (WHO) has reported that the Covid-19 variant known as Kraken has spread across the United States and is now present in at least 28 other countries.
According to Bloomberg on January 5, the “Kraken” variant was first identified last year and quickly became the dominant strain in the U.S.
Named after the mythical sea monster from Norwegian folklore by Western media, “Kraken” is officially designated as XBB.1.5. It is a descendant of the Omicron subvariant XBB, resulting from a hybrid of two earlier strains: BA.2.75 and BA.2.10.1.
The XBB variant initially triggered a wave of Covid-19 cases in countries including Singapore and India following the WHO’s warning in October of the previous year.
“Kraken” also has the ability to evade vaccine-induced immunity. (Photo: Bloomberg)
Although it accounted for only 1% of total Covid-19 cases in the U.S. at the beginning of December 2022, estimates from the Centers for Disease Control and Prevention (CDC) indicate that “Kraken” became the dominant strain by the end of that month, representing about 41% of total Covid-19 cases. In the Northeastern states of the U.S., this figure rose to over 70%.
During a press conference on January 4, WHO’s technical lead on Covid-19, Maria Van Kerkhove, stated that XBB.1.5 is the “most transmissible subvariant detected to date.”
This variant accounted for approximately 4% of Covid-19 cases in the UK as of mid-December 2022, with Canada also reporting several similar cases.
XBB.1.5 has drawn attention due to its potential to evade natural immunity or the protection afforded by vaccines, and it can reinfect individuals who have previously recovered from earlier Covid-19 infections.
Data regarding the severity, trends of worsening disease, or mortality associated with XBB.1.5 remain limited.
Many scientists have warned that subvariants like XBB pose a “serious threat” to the current Covid-19 vaccines. Their higher transmissibility increases the likelihood of infection, resulting in potentially more severe outcomes.
WHO is expected to release an updated assessment of the risk posed by the XBB.1.5 variant in the coming days.
