Virologists have voiced concerns about another highly-contagious Omicron variant which has arrived in the UK.
The BA.2.75 variant, nicknamed Centaurus, is rapidly gaining ground in India after first being detected there in May.
The new variant is thought to spread at an even faster rate than its Omicron relatives BA.5 and BA.2 variants and it has now been detected in about 10 other countries, including the UK, US, Australia, Germany and Canada.
It remains unclear whether it could cause more serious disease than other Omicron variants, but scientists say it may be able to get around immunity from vaccines and previous infection.
The European Center for Disease Prevention and Control (ECDC) designated BA.2.75 as a “variant under monitoring” on 7 July, meaning there are indications it could be more transmissible.
Experts’ concerns are being fueled by the large number of mutations BA.2.75 contains compared to its Omicron predecessors.
Some of those mutations are in areas that relate to the spike protein and could allow the virus to bind onto cells more efficiently, said Matthew Binnicker, director of clinical virology at the Mayo Clinic in Rochester, Minnesota.
Another concern is that the genetic tweaks may make it easier for the virus to skirt past antibodies –the protective proteins made by the body in response to a vaccine or infection from an earlier variant.
But experts say vaccines and boosters are still the best defense against severe Covid-19.
It may take several weeks to get a sense of whether the latest Omicron mutant may affect the trajectory of the pandemic.
Shishi Luo, head of infectious diseases for Helix, a company that supplies viral sequencing information to the US Centers for Disease Control and Prevention, said BA.2.75 is another reminder the coronavirus is continually evolving – and spreading.
“We would like to return to pre-pandemic life, but we still need to be careful,” she said.
“We need to accept that we’re now living with a higher level of risk than we used to.”
The World Health Organization (WHO) has said Covid-19 remains a global emergency, almost two and a half years after it was first declared.
The Emergency Committee, made up of independent experts, said in a statement that rising cases, ongoing viral evolution and pressure on health services in a number of countries meant the situation was still an emergency.
The number of new coronavirus cases reported worldwide have risen for the fifth week in a row while the number of deaths remains relatively stable, WHO reported on Thursday.
In the UN health agency’s weekly review of the Covid pandemic, WHO said there were 5.7 million new infections confirmed last week, marking a 6 per cent increase. There were 9,800 deaths, roughly similar to the previous week’s figure.
Earlier this week, WHO director-general Tedros Adhanom Ghebreyesus said the pandemic still qualifies as a global emergency and he was “concerned” about the recent spike.
“The virus is running freely, and countries are not effectively managing the disease burden,” he said.
“New waves of the virus demonstrate again that Covid-19 is nowhere near over.”
In the last two weeks, cases of Covid-19 reported to WHO surged 30 per cent, driven largely by the hugely infectious Omicron relatives, BA.4 and BA.5.