21 Oct 2021 11:56

New subvariant of Delta more contagious, could replace initial strain in future - Rospotrebnadzor expert

MOSCOW. Oct 21 (Interfax) - A new subvariant of the Delta strain of Covid-19, AY.4.2, is more contagious and could replace the initial variant, but Russian vaccines will be effective against this strain of coronavirus, Kamil Khafizov, head of the research team for the development of new methods of human disease diagnostics at the Central Research Institute of Epidemiology of Russian consumer health watchdog Rospotrebnadzor, told reporters on Thursday.

"Probably, it may be approximately 10%, according to foreign studies, more transmissible, i.e., more contagious, than the original Delta. That's not that much as compared to what we saw when first encountering the Alpha and Delta strains, which were 50%-60% more contagious than the previous variants," Khafizov told reporters on Thursday.

At the same time, Khafizov believes that the new subvariant of Delta might gradually begin to replace the initial strain.

"But that's unlikely to happen at the same rapid pace at which Delta itself ousted all other variants previously. For instance, it was first detected in July, and the share of this Delta lineage has been slowly increasing. Potentially, this is a strain which is only slightly more contagious," he said.

However, Khafizov is convinced that the Covid-19 vaccines registered in Russia will be effective against this new Delta subvariant.

"The vaccines are sufficiently effective against this virus variant, which isn't so different as to be able to radically alter the ability to link with antibodies," he said.

"AY.4.2 has two telltale mutations in the S protein gene, thus causing Y145H and A222V amino acid replacements," Khafizov said.

"And if we go by the fact that it has mutations precisely in the S protein, then it is likely to be more about transmissibility than the severity of the disease," he said.

Vaccination alone is able to protect the population against the spread of this new subvariant of the Delta strain, Khafizov said.

"However, the emergence of the initial Delta strain has already caused a surge in morbidity rates, and AY.4.2 may give an additional boost as morbidity rates keep growing. The only thing that can help counter the new variant is vaccination, especially of people who have not had Covid-19," he said.

Earlier this week, UK scientists reported the spread of a subvariant of the Delta strain, AY.4.2, which is more contagious than the Delta strain itself.

The Delta variant of Covid-19 began actively spreading across Russia in late spring and early summer of this year, causing a spike in morbidity rates. Delta is currently the dominant Covid-19 strain in Russia.