COVID-19: New subvariant Kraken detected in New Zealand

The new COVID-19 subvariant Kraken has been found in New Zealand for the first time.

XBB.1.5, as it is officially known, is a descendant of the Omicron XBB subvariant.

The Ministry of Health said on Monday the Institute of Environmental Science and Research (ESR) reported the whole genome sequencing results for two COVID-19 cases with the subvariant late last week.

"The list of new subvariants appearing within New Zealand is lengthy and growing," the Ministry of Health said in a statement.

"Many of these new subvariants are identified by their mutations, but it can take weeks or months to determine whether these mutations will allow a subvariant to out-compete others circulating in the community.

"At the early stage of a new variant being identified in New Zealand, it is difficult to predict whether and when it will become established in the community."

The Ministry of Health said the detection of XBB.1.5 is not unexpected. It was recently found in Australia and elsewhere around the world, and the ministry said New Zealand's COVID-19 response accounts for the emergence of new variants.

"So far, most Omicron variants have not demonstrated a change in severity of the disease, and there is no evidence at this stage to indicate XBB.1.5 causes more severe disease compared to other variants," the Ministry of Health said.

"The proportion of COVID-19 cases in the USA caused by the XBB.1.5 sub-lineage has been rapidly increasing in recent weeks, after having first been detected there in late October 2022.

"XBB.1.5 appears to be outcompeting other XBB sub-lineages and BQ.1.1 in the USA. It remains unknown how XBB1.5 will compete against other variants in a New Zealand context, and whether this could affect the level of COVID-19 circulating in the community in the coming months."

The ministry said that, relative to other parts of the world, New Zealand currently has a high level of immunity based on high vaccine uptake combined with a recent wave of infections - a "so-called 'hybrid immunity'".

They added that vaccines are still expected to give protection against severe disease from Kraken, particularly in those who have received boosters.