XBB.1.5 is 'most transmissible' Covid variant yet, says World Health ... trends now
A Covid strain spreading rapidly in the US is the 'most transmissible subvariant that has been detected yet', according to the World Health Organization.
But there are no signs XBB.1.5 is more deadly than previously dominant variants, with hotspots in Northeast America yet to record an uptick in hospital admissions.
The new subvariant - another spinoff of Omicron - is behind roughly 70 percent of new infections in the Northeastern US and four in 10 nationally.
It has spread rapidly in recent weeks, accounting for just four percent of US cases in early December, indicating it has a major growth advantage over rival strains.
A highly contagious Covid strain has emerged and is already behind three in four cases in some parts of the US, surveillance data shows
US COVID CASES: Covid infections nationally have started to tick up in recent weeks, with around 400,000 weekly cases now compared to 300,000 a month ago
US COVID DEATHS: Fatalities have flatlined since the summer, a trend attributed to high levels of population immunity
US COVID HOSPITALIZATIONS: Hospital admissions among people with Covid have also risen in recent weeks - but pale in comparison to last year. There were around 6,500 admissions for the virus across the US every day last week, on average — around double the number in early November
Dr. Maria Van Kerkhove, WHO's technical lead for Covid, told a press conference Wednesday: 'We are concerned about its growth advantage in particular in some countries in Europe and in the US... particularly the Northeast part of the United States, where XBB.1.5 has rapidly replaced other circulating variants.
'Our concern is how transmissible it is, … and the more this virus circulates, the more opportunities it will have to change.'
XBB.1.5 has gained 14 new mutations to the virus’ spike proteins compared with its ancestor strains, which appear to have given it enhanced antibody-resistance.
This means people who are vaccinated or have had a previous infection are more susceptible to an infection - though not necessarily severe illness.
Antibodies are just one part of the overall immune response to Covid, with other virus-fighting substances like
