The majority of people of South Asian descent carry a gene that makes them extra vulnerable to severe Covid-19, says a study by British researchers. While they cite the findings to explain the relatively high rate of deaths and hospitalisations witnessed in the UK among people from the subcontinent, it has been pointed out that there can be other factors at work, too, which may be equally important in explaining the higher prevalence of serious cases among some communities.
What Does The Gene Do?
Researchers at Oxford University have identified what they say is a “relatively unstudied gene called LZTFL1″, which their study has linked with a doubling of the risk of respiratory failure from Covid-19.
The study says that the higher-risk version of the gene — which “probably prevents the cells lining airways and the lungs from responding to the virus properly” — is carried by 60 per cent of people with South Asian ancestry while it was found in only 15 per cent of those of European descent. That, the researchers said, explains “in part the higher death rates and hospitalisations” among South Asians in UK as also the devastating impact of the second wave of cases in India in the early part of 2021.
Reports said while this gene acts as a trigger for activating a key defence mechanism to prevent the Covid-19 virus from entering the cells that line the lung, its high-risk version tamps down on the switch, thus blunting the response to the novel coronavirus, which causes the Covid-19 infection. That allows the virus to enter the lung cells and exercise its damaging impact with ease for a longer duration after exposure.
How Do The Findings Help?
Amid the pandemic, research has pointed to how biological differences between men and women, including at the genetic level, could explain why although both sexes were equally likely to acquire a Covid-19 infection, it was the men who face “a higher risk of severe illness and death”.
Covid-19 resource UK Research and Innovation (UKRI) notes that while “any two people have genomes that are roughly 99.9 per cent the same; it is the remaining 0.1 per cent that makes them different”. This variation, it adds, “may be important in determining how different people respond to particular infections”.
The Oxford University study, which utilised previous research and machine learning “to analyse huge quantities of genetic data”, only “partly explain the excess deaths seen in some communities in the UK and the impact of Covid-19 in the Indian subcontinent”, but where it can prove helpful is in leading to the development “new treatments customised for those most likely to develop severe symptoms”.
The researchers said that their findings hinted at the promise that new treatments may hold if they’re designed to target the lung cells’ response to an attack by the novel coronavirus. Most current treatments work by changing the way the immune system responds to the virus, they pointed out.
Also, while the high-risk version of the gene under study was found to mute the trigger against respiratory attack, the researchers said it doesn’t affect the immune system. That means that people carrying this version of the gene would respond normally to vaccines.
“Although we cannot change our genetics, our results show that the people with the higher-risk gene are likely to particularly benefit from vaccination,” said James Davies, the co-lead for the study. “Since the genetic signal affects the lung rather than the immune system, it means that the increased risk should be cancelled out by the vaccine.”
Do Genes Explain All The Variations In Cases, Deaths?
The South Asian communities in UK were not the only ones to bear an outsize brunt of the pandemic. Higher death rates were also reported among black and minority ethnic communities in UK although the prevalence of the high-risk version of LZTF1 is miniscule for these groups.
For example, only 2 per cent of people from African-Caribbean backgrounds and 1.8 per cent of people of East Asian descent had the gene, the researchers pointed out, “meaning that this genetic factor does not completely explain the higher death rates reported for black and minority ethnic communities”.
Reports though say that in England’s second wave of Covid cases, the risk of death was 3-4 times higher for people of Bangladeshi origin and 2.5-3 times higher for those of Pakistani background. As for people of Indian descent, their risk factor was 1.5-2 times higher than the general population.
The researchers do admit that socio-economic factors can also play a part in determining the level of Covid affliction. “The higher risk DNA code is found more commonly in some black and minority ethnic communities but not in others. Socio-economic factors are also likely to be important in explaining why some communities have been particularly badly affected by the Covid-19 pandemic,” Davies said.
While India is second only to the US on the cumulative burden of Covid-19 cases — it’s third in terms of the death toll, behind the US and Brazil — its caseload seen as a proportion of the population has remained considerably lower than that for the likes of the UK.
Data till November 3 shows that the US and UK both had more than 130,000 cases per every million population as compared with a little under 25,000 cases for India. As for deaths, data till November 2 said that the US and UK had more than 2,000 fatalities per million population whereas the figure stood at 330 for India.
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