The Buyt Desk
A sub-lineage of the Omicron SARS-CoV-2 virus strain which is highly contagious than the original has been detected in 57 countries.
The Omicron name was given to the lineage of SARS-CoV-2 virus B.1.1.529 once it was considered as a variant of concern. Research showed that this lineage has a little deviation of its own, and these variants were named B.1.1.529.1, B.1.1.529.2, and B.1.1.529.3. These sub-lineages were later re-classified for ease of usage as BA.1, BA.2 and BA.3.
Till now, the Omicron sub-variant BA.1 is most common in circulation. Even now the scenario is the same, but the BA.2 variant proportion is on the rise. As per the WHO findings, based on Omicron genetic sequences submitted in global databases, 98.8 % was BA.1 variety till January 25, 2022. BA.2 has most of the characteristics of BA.1 and has more mutations compared to BA.1 that can give it a distinctive characteristic. This makes BA.2 more contagious than the original strain which is BA.1. Also, a new study has revealed that BA.2 is better at infecting the vaccinated as compared to BA.1. This new variant is detected globally in 54 countries. It is most likely that it has driven the third COVID wave in some Indian states including Delhi, Gujarat and Karnataka.
At what rate does the BA.2 sub-variant spread?
BA.2 was first detected in Denmark and many studies were conducted on this new variant. An analysis was done on the data gathered in December and January from 8,541 households in Denmark. This revealed that the dominant strain is the new sub-variant. Also says that on the whole 39% is the secondary attack rate in BA.2 infected families compared to 29% in BA.1 infected families. Other than Denmark, the sub-variant is already dominant in the Philippines, Nepal, Qatar and India. BA.2 sub-variant is swiftly replacing BA.1.
Can vaccines protect you?
The UK Health Security Agency says that household transmission among contacts of people infected with BA.2 is higher compared with other Omicron cases, approximately 3% higher. The Danish researchers have proof to support that the sub-variant BA.2 has immune evasive properties. The health officials have said, “When comparing BA.2 relative to BA.1 infected households, there was an increased risk of infection in BA.2 infected households regardless of the vaccination status of the potential secondary case, indicating inherent increased transmissibility of the BA.2 sub-variant”. The data collected says that
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Unvaccinated BA.2 infected primary individuals transmit the infection to a higher degree than BA.1 infected primary individuals, to both vaccinated and booster-vaccinated household members.
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A vaccinated individual infected with BA.2 transmit less than a vaccinated individual infected with BA.1.
Can one infected by BA.1 earlier be re-infected by BA.2?
The study on data collected suggests that mild cases of BA.1 may not provide good protection against future infections. The milder cases of omicron infection in vaccinated individuals may leave the recovered vulnerable to future and existing variants. The studies conducted in the University of California, San Francisco says that the antibodies production in infected individuals is proportional to the severity of the illness.
WHO on sub-variant BA.2
Maria Van Kerkhove who is one of the WHO’s top experts on the current pandemic, held a press meet on February 1st, 2022 to share information about the sub-variant BA.2. She said that with some initial limited data it is inferred that BA.2 had “a slight increase in growth rate over BA.1”. She also said that the coronavirus variant Omicron is known to cause less severe disease compared to previous variants like Delta. She said with respect to the BA.2 sub-variant so far there is “no indication that there is a change in severity”. She emphasized that COVID has always been a risky disease and people should be careful and avoid the spread. She said, “We need people to be aware that this virus is continuing to circulate and it’s continuing to evolve. It’s really important that we take measures to reduce our exposure to this virus, whichever variant is circulating.”
Regarding the sub-variant of Omicron BA.2, World Health Organization chief, Dr Tedros Adhanom Ghebreyesus clearly emphasized the necessity for continuous tracking of emerging variants, he said, “This virus will continue to evolve, which is why we call on countries to continue testing, surveillance and sequencing”. He also mentioned that in just 10 weeks, since Omicron was first detected in southern Africa, more than 90 million cases have been reported to the WHO. This number accounts for more than cases of 2020 put together. He stressed that considering the new COVID variant is milder but “we are now starting to see a very worrying increase in deaths in most regions of the world.”
