The latest Omicron subvariant XBB.1.5 – a highly-contagious new Covid variant – is responsible for more than 40% of confirmed COVID cases in the United States, the US Centers for Disease Control and Prevention (CDC) informs noting that the new variant sweeps across both sides of the Atlantic.
Noting that cases have doubled from the previous week, the latest weekly estimate of proportions of circulating variants shows 40.5% of COVID infections in the country have been attributed to XBB.1.5.
Per Dr. Michael Osterholm, an infectious disease expert at the University of Minnesota, XBB is probably the worst variant that the world is facing right now, warning that the XBB.1.5 variant is becoming a major threat after data showed that in seven of the 10 US states in the north-east where COVID cases and hospitalizations are rising, its concurrent with an increase of XBB cases there.
Citing CDC data, Dr. Osterholm pointed out that for the week ending Dec 24, XBB.1.5 had made up 21.7% of the total cases in the US while for the week ending December 31, the combinations of the XBB and XBB.1.5 variants, together accounted for 44.1% of the total cases.
The concerns regarding this new variant have been increased additionally by the fact that the XBB strain has also been driving up cases in parts of Asia – including Singapore – after it was first detected in India in August.
Wilbur Lam, who runs the US National Institutes of Health’s RADx Tech Testing Validation Core, noted that the situation in China is making them very worried and experts have even raised concerns that available vaccines may not be effective.
According to a study that researchers from Columbia University published last month, the new Omicron subvariants may have gained dominance in the population because of their advantage in evading antibodies and present serious threats to current Covid-19 vaccines, rendering inactive all authorized antibodies.
On top of that, mutations have rendered at least one Covid test unreliable, US regulators said last week although scientists, in general, say that when omicron infections are present, it takes a bit longer for tests to turn positive.
The newest data comes in light of the CDC announcement last week that all travelers from China, Hong Kong, or Macau – regardless of nationality or vaccination status – will be required to show a negative PCR COVID-19/antigen self-test test results no more than 2 days before flying to the US.
The order also applies to travelers connecting through the United States to another country or traveling from China via a third country, noting that airlines can deny boarding for the traveler that doesn’t present with negative test results.