New Omicron Subvariant With Higher Transmissibility Detected In New Delhi. What We Know So Far

A new subvariant of the Omicron variant of SARS-CoV-2 was detected in New Delhi on Wednesday, August 10, according to a health official.

The immunogenicity (ability of a foreign body to stimulate an immune response in a host) of BA.2.75 was different from that of BA.2 and BA.5. The study found that three clinically-available antiviral drugs were effective against BA.2.75. | Representational Image

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A new subvariant of the Omicron variant of SARS-CoV-2 was detected in New Delhi on Wednesday, August 10, according to a health official. The new subvariant, named BA.2.75, was detected in a study report of 90 samples that had been sent for genome sequencing, news agency ANI reported.

BA.2.75 has more transmissibility, and hence, infects even the hosts with antibodies, according to Dr Suresh Kumar, Medical Director of LNJP Hospital, New Delhi.

Quoting Dr Kumar, the ANI report said that Omicron's subvariant BA.2.75 has been found in the study report, and that it has a higher transmission rate compared to previous subvariants. He added that the new subvariant also attacks people already having antibodies and the vaccinated.  

What We Know So Far About BA.2.75

The study was recently published on bioRxiv, a preprint server for biology. According to the study, the Omicron subvariant BA.2.75 emerged in May 2022, and is a descendant of BA.5, which is the currently predominant BA.2 descendant. However, BA.2.75 is phylogenetically different from BA.5.

The effective reproduction number of BA.2.75 is greater than that of BA.5. The effective reproduction number is the average number of secondary cases per infectious case in a population made up of both susceptible and non-susceptible hosts. A person who contracts a disease from exposure to a person with the disease is called a secondary case. 

According to the study, the sensitivity of BA.2.75 to vaccination-induced humoral immunity is comparable to that of BA.2. Humoral immunity refers to the manifestation of adaptive immunity through the production of antibodies by B lymphocytes. 

However, the immunogenicity (ability of a foreign body to stimulate an immune response in a host) of BA.2.75 was different from that of BA.2 and BA.5. 

The study found that three clinically-available antiviral drugs were effective against BA.2.75. 

Also, the spike protein of BA.2.75 exhibited a higher affinity to the human ACE2 receptor compared to BA.2 and BA.5 spike proteins.

The growth efficiency of BA.2.75 in human alveolar epithelial cells, and the intrinsic pathogenicity (capacity of an organism to cause disease) in hamsters were comparable to those of BA.5, but greater than those of BA.2, the study said.

According to the authors, their investigations suggest that BA.2.75 acquired virological properties independently of BA.5, and the potential risk of BA.2.75 to global health is greater than that of BA.5.