A new variant of coronavirus is spreading rapidly in America, leading to worries that there may be a new wave of infections in 2023.
The XBB.1.5 variant is related to Omicron, a highly infectious type of Covid, and is descended from the XBB variant which was widely spread in Singapore and in India in the Autumn. A study in the medical journal Cell suggested that XBB is better at avoiding the immune defences built up by vaccination and previous infection compared to other variants, which raises the fear that previous patient may be infected again. Though the World Health Organisation said in October that XBB is not a more serious type of the virus than other strains, it is highly transmissable.
In America, there are fears that low levels of vaccination booster uptakes may lead to a surge in XBB. 1.5 infections. In the UK, where vaccination rates are relatively high, this might not be such a worry – but the NHS, already having to cope with seasonally high levels of influenza infections as well as other respiratory diseases such as RSV, is understandably worried that XBB. 1.5’s mutation may make it more resistant to vaccination.
Diagnosis
In the last week of 2022, XBB.1.5 accounted for 40.5% of new COVID-19 cases in America, according to data from the U.S. Centers for Disease Control and Prevention (CDC). In the north-east, the figure is even higher at around 75 percent. Representative diagnostic testing is showing about 40 percent positive and hospital admissions are rising, though it’s not yet certain how much of this is due to XBB. 1.5.
While there’s no specific vaccination against XBB. 1.5, and it does seem to be more resistant to immunisation that previous strains of the virus, small-scale studies suggest that the Pfizer/BioNTech bivalent booster, which targets both the original virus and the Omicron BA.4 and BA.5 sub-variants, provides better protection than standard vaccinations. But only 15 percent of the population of America aged over five have had a bivalent booster, so levels of protection there are relatively low.
There’s also some concern as to whether the monoclonal antibody treatments used to treat Covid symptoms are as effective against XBB. 1.5 infection. This could be a particular worry for people with compromised immune systems. It’s not yet clear whether XBB. 1.5 can cause particularly high levels of enduring symptoms, know as ‘long Covid’.
There have been suggestions in America of a return to disease prevention measures such as wearing masks, improving ventilation and restricting group gatherings.
Analysis
In the UK, since the amount of genetic sequencing of Covid samples has decreased, it’s not yet clear what percentage of infections might be due to XBB. 1.5, but the Sanger Institute suggests that it may be around four percent of current infections. XBB.1.5 has also been identified in countries including France, Germany, the Netherlands, Spain, Ireland, Australia, Singapore and India.
Ironically, the rise of influenza infections might actually blunt the effect of XBB. 1.5, as the immune system should already be activated by any attack from viruses.
Professor Lawrence Young, a virologist at Warwick University, said: “We don’t know how this variant is going to behave in the UK, in a population that has been previously exposed to other Omicron variants and where many of the over 50s have had booster shots with a bivalent vaccine.
“Nevertheless, this is a wakeup call — a sharp reminder that we can’t be complacent about Covid. The threat of XBB.1.5 and other Covid variants further exacerbating the current NHS crisis stresses the need for us to remain vigilant.
“We need to continue to monitor levels of infection with different variants in the UK, encourage those who are eligible to get their boosters shots — why not extend this to the under 50s? — and promote the value of other mitigation measures.”
See also: Fears of New Covid Wave in China
