A newly-discovered mutation of the delta variant is being investigated in the U.K. amid worries that it could make the virus even more transmissible and undermine Covid-19 vaccines further.
Still, there are many unknowns surrounding this descendent or subtype of the delta variant — formally known as AY.4.2 — which some are dubbing the new “delta plus” variant.
U.K. government health officials have said it’s too early to tell whether the mutation poses a greater risk to public health than the delta variant, which itself is significantly more infectious than the original Covid-19 strain (and its successor, the alpha variant).
But they have stated that they are monitoring the mutation very closely: it now accounts for 6% of U.K. Covid cases that have been genetically sequenced at a time when infections in the country are rising rapidly.
AY.4.2 is being identified in an increasing number of U.K. Covid cases, with some suggesting it could be a factor in the country’s growing health crisis that has prompted some doctors to call for Covid restrictions to be reimposed.
The U.K. is currently seeing a prolonged and worrying spike in Covid cases, reporting between 40,000-50,000 new infections per day in the last week, prompting experts to question why the U.K. is so vulnerable to Covid right now.
The delta subtype is reported to be 10-15% more transmissible than the standard delta variant, but it is too early to say for certain whether it has been causing a spike in cases in the U.K.
Finding a potentially more transmissible variant matters because it could cause more Covid cases among the unvaccinated.
A large part of the world remains unvaccinated (only 2.8% of people in low-income countries have received at least one dose of a Covid vaccine, according to Our World in Data) while developed countries are seeing more and more “breakthrough” cases as immunity to Covid wanes around six months after being fully vaccinated.
A more infectious variant could undermine vaccine efficacy even further, although there is no indicated that is the case yet with the AY.4.2 subtype.
Health officials are remaining calm about the delta subtype, for now, noting that it’s crucial to keep an eye on the mutation but not to panic.