The omicron subvariant XBB.1.5, which some have dubbed the most transmissible strain yet of the virus that causes COVID-19, has been detected in Hawaii County.
According to the variant report released Wednesday by the state Department of Health, XBB and XBB.1.5 account for roughly 19% of total confirmed COVID-19 cases that have been sequenced in Hawaii County for the two-week period ending Dec. 31.
“XBB.1.5 currently accounts for an estimated 5% of the COVID-19 cases in Hawaii,” said DOH spokesperson Brooks Baehr of the statewide numbers. “That number is growing.”
XBB.1.5 is considered a recombinant variant, meaning two different strains from the BA.2 lineage joined together during an infection to form a new strain with shared properties.
Because XBB.1.5 is a subvariant of the omicron strain, bivalent boosters offer some protection against infection.
“We continue to see that primary vaccination and subsequent boosters against COVID-19 protect against severe outcomes from COVID-19, including newer variants,” Baehr said. “This effect doesn’t necessarily depend on how good a ‘match’ there is between the booster formulation you got and the strain with which you get infected.”
For Hawaii County, 19.2% of the population has received a bivalent booster as of Jan. 16.
Wastewater reports released last week show other variants including BA.2.75, XBB.1.5 and other XBB lineages also have been detected in wastewater samples from all counties except Kauai.
“The wastewater data is concerning, but not alarming,” State Epidemiologist Sarah Kemble said in a statement. “The detection of higher virus concentrations means we should closely monitor case counts and hospitalizations for a possible surge in cases and be ready to respond should a surge materialize.”
XBB and XBB.1.5 are the subvariants with the greatest immune-evasive properties.
First detected in New York, the U.S. Centers for Disease Control and Prevention’s initial data on XBB.1.5 indicates the strain is spreading faster than all other major strains seen during the pandemic so far in the U.S., except the original omicron lineage that resulted in a record number of infections last year.
XBB.1.5 is now the dominant variant in the Northeast of the U.S., where the CDC estimates it accounts for roughly 70% of total cases.
In all other regions, the strain accounts for less than a third of all cases.
The DOH is cautioning individuals that XBB.1.5 could become the dominant strain in Hawaii, but is waiting for additional information.
“While we can’t say with absolute confidence that XBB.1.5 will become the dominant strain in Hawaii or how quickly that may happen, we do know the World Health Organization says XBB.1.5 has a growth advantage that will likely lead to global predominance,” Baehr said.
With increased presence of XBB.1.5 in the state and county, the DOH said it may be a good time to consider masking up again in certain situations.
“It is still a good idea to wear masks in large crowds, when traveling, and when indoors in close proximity to people from outside your household,” said Baehr. “This is especially true for kupuna, people with underlying conditions, and those with compromised immune systems.”
Email Grant Phillips at gphillips@hawaiitribune-herald.com.