The new sub-variant of Omicron – BA.4.6 – is no cause of concern, say health experts of Mumbai. It is a derivative of the BA.4 variant. However, Omicron infections in general are less serious and have caused fewer deaths as compared to other variants. Doctors said the BA.2.75 sub-variant is the major cause for the surge in cases across Maharashtra.
According to Dr Ishwar Gilada – consultant in HIV and infectious diseases, and secretary general of Organised Medicine Academic Guild (OMAG) – a study in the UK indicated a jump from 3 per cent to 9 per cent in total Covid cases in August 2022, owing to the BA.4.6 sub-variant. “However, there is still no cause of concern as it neither causes higher mortality nor higher morbidity, and there has been no increase in hospitalisations following infections,” Dr Gilada said.
The BA.4 sub-variant was first detected in January 2022 in South Africa and has since spread around the world, along with the BA.5 variant. However, neither of these sub-variants is common in India. “It's possible it could be a recombinant variant which can happen when two different variants of SARS-CoV-2 infect the same person, at the same time. Moreover, it has immune escape but if the infection doesn't lead to increased morbidity and mortality,” he said.
Dr Sanjith Saseedharan, consultant & head of critical care at SL Raheja Hospital, said the BA.4.6 is now gaining momentum in the US and UK. “However, it has a slight growth advantage over the earlier variant. As with the Covid sub-variant case, this variant is not as severe as the earlier Delta variant,” he said.
“There is no indication that this variant has caused serious outcomes to date. This variant (given the mutation it carries) would have the property of immune evasion. There has been no data on this variant in India, although data from other countries suggests that vaccination remains the best weapon to prevent serious illnesses. However, this variant is a reminder that the virus still exists and is finding ways to change and evade immunity. Hence it is still significant for the elderly and individuals with comorbidities to follow Covid-appropriate behaviour, which includes avoiding crowded spaces and wearing masks in public areas,” said Dr Saseedharan.
Dr Anant Pandhare, medical director at Dr Hedgewar Hospital (BAVP) said it is not yet entirely clear how the BA.4.6 sub-variant emerged, but it's possible it could be a recombinant variant. BA.4.6 carries a mutation to the spike protein which helps it with immune evasion, wherein it helps the virus to escape antibodies acquired from vaccination.
“We are still learning about how the BA.4.6 variant impacts vaccination. Its emergence and that of other new variants is concerning. It shows the virus is still around us and is mutating to find new ways to overcome our immune response from vaccination and previous infections. Data suggests that Covid vaccines are still very effective at preventing serious illness and death against all of the current variants of concern,” he said, adding that it is important to note that vaccines provide different levels of protection from infection, mild disease, severe disease, hospitalisation and death.
