Like movie remakes have become common in India, many versions of Omicron are circulating in the country, with the latest sub-variant, BA.2.75, behind the spike in Covid-19 cases in Delhi.
The Covid positivity rate of Delhi has jumped close to 20%, with around 1,700 new cases reported in the last 24 hours. The new Omicron sub-variant, BA.2.75, has been identified as highly transmissible and can infect those who have antibodies, experts have pointed out.
Although the rise in infections and hospitalisations is not yet alarming, experts have stressed the need to wear masks and follow Covid-appropriate behaviour.
Dr Suresh Kumar of LNJP Hospital, Delhi, said the new sub-variant has more transmissibility which infects even those with antibodies. “This new sub-variant also attacks people already having antibodies and also those who have taken the COVID vaccines in their body,” Dr Kumar told news agency ANI.
Let’s take a look at the new BA.2.75 variant
The new sub-variant was first detected in Maharashtra in July, and later its cases were reported in the UK, US, Canada, Germany and Australia. The World Health Organization (WHO) has described it as a “variant of concern lineage under monitoring”. WHO chief Soumya Swaminathan has said the variant seems to have a few mutations on the receptor-binding domain of the spike protein but it is too early to predict if the virus is clinically more severe.
The BA.2.75 does not show any distinct symptoms but is likely to cause a low-grade fever, body ache, fatigue and upper respiratory tract infection. Some patients may also remain asymptomatic. The new sub-variant cannot be detected with an RTPCR test. Therefore, genome sequencing is the only effective method to identify it.
The BA.2.75 can infect those who had Covid and can evade immunity as gained by the patient.
India has reported 12,608 new coronavirus cases and 72 deaths on August 18.
According to senior virologist Dr Gangangdeep Kang, the surge in cases could be due to the sub-variant’s ability to escape immune response. She stressed that those who have not received booster dose, should get one as it will reduce the risk of severe disease, as told to Moneycontrol.
Other Covid variants, which are still circulating in India are:
What are BA.5 and BA.4?
The BA.54 and BA.5 coronavirus variants, part of the Omicron family, were behind 52% of cases sequences last June in India, up from 37% in one week. The BA.5 variant is behind 60% of infections in the US.
BA.5 was first tracked in January, and is a sister variant of Omicron strain that has been dominant worldwide since end of 2021. The BA.4 and BA.5 sub-variants were first detected in India in May. It had caused spikes in cases in countries including South Africa, where it was first found, UK, and parts of Europe and Australia.
The first BA.5 case in India was detected late May in Telangana.
“BA.5 has a growth advantage over the other sub-lineages of Omicron that are circulating,” Maria Van Kerkhove, the WHO’S technical lead of Covid-19 had told Reuters.
There is no evidence that BA.5 is more dangerous than any other Omicron variants, although spikes in cases have increased hospitalisations.
Both BA.5 and BA.4 carry L452R and F486V that can evade immunity and infect the lungs, as was found in Delta variant.
The rise of BA.4 and BA.5 seem to be caused by their ability to infect people who were immune to Omicron and other variants, according to a few experts.
BA.2.38 Causes Mild Disease
BA.2.38 is an offspring of BA.2 sub-variant and was mainly found in cases reported in Mumbai and Pune. It may be causing illness as common as cold. According to a Times of India report, Dr Rajesh Karyakarte, lead investigator of a clinical study off 116 patients infected with BA.2.38, said those infected with the sub-variant predominantly had fever, cough, body ache, sore throat and headache.
A few patients also experienced gastro-intestinal symptoms like diarrhoea, along with vomiting and stomach ache.
It has now been established that BA.2.38, which was recently re-classified, is leading to milder disease, just like its parent variant BA.2.
BA.2.12.1 Can Evade Immunity
BA.2.12.1 is a descendent of BA.2 variant, and from sister lineage of BA.2.12 and was first detected in Australia and New Zealand. It has reported symptoms such as cough, fatigue, congestion and runny nose.
The BA.2.12.1, which has L452Q found in the Delta variant, has increased the virus’ infectivity.
Many studies in the US have found that the BA.2.12.1 may have significantly increased growth advantage over the Omicron lineage. Early research had suggested that the BA.2.12.1 evades body’s immune defences due to the presence of L452Q mutation.
The BA.2.12.1 could be behind the rise in Covid-19 cases in Delhi in April.
(With inputs from agencies)
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