Scientists have discovered a gene common in South Asian people that doubles the risk of death from Covid.
Oxford University researchers found the LZTFL1 gene — present in 60 per cent of South Asians — allows the virus to multiply in the lungs easier.
For comparison, it is only found in 15 per cent of European people and two per cent of black Africans.
Scientists say the genetic quirk may partly explain why South Asian people in the UK have been disproportionately affected by Covid.
But they emphasised the single gene is not the sole reason for the disparity, and highlighted the seriousness of social and economic factors.
Office for National Statistics data show Bangladeshi men were nearly five times as likely to die with the virus than their white counterparts during the second wave of the pandemic in England.
Pakistani men were the second most affected (3.4 times as likely), while Indian men were the fourth worst hit ethnic group (1.95 times as likely).
Scientists have discovered a gene found in 61.2 per cent of people with South Asian ancestry that doubles the risk of death from Covid
Covid deaths in the second wave were up to five times higher in Bangladeshi Brits than white adults in England, ONS data has shown
Figures from the Office for National Statistics (ONS) show fatalities were worst in Black African Britons last spring
Covid deaths in second wave were up to FIVE TIMES higher in Bangladeshi Brits compared to white adults
Covid deaths in the second wave were up to five times higher in Bangladeshi Brits than white adults in England, official data revealed today.
Figures from the Office for National Statistics (ONS) show Britons from the ‘Black African’ demographic group were worst-hit last spring.
But the trend has changed between the first and second waves, according to the Government’s statistical body.
The ONS analysis — which goes up until the end of March — crunched the data of every coronavirus victim aged 30-100 listed on the 2011 census.
It showed Black African Britons, a group distinct from people with Black Caribbean backgrounds, were 3.7 times more likely to die than white people in the first wave, up to September 11. That dropped to 1.62 in the second wave, considered as starting the day after.
For comparison, the risk among Bangladeshi Brits went from three to 4.96.
The ONS offered no explanation as to why coronavirus deaths were higher in BAME people, or why the second wave hit certain communities harder.
Scientists investigating the topic have repeatedly claimed a number of factors are behind the link, including ethnic minorities being more likely to be key workers who come into contact with more people.
Other included living in crowded housing, where transmission is more likely, as well as having underlying conditions that raise the risk of getting seriously ill.
Experts had previously found a stretch of DNA could double the risk of dying in adults aged 65 and above but were not aware of the exact gene that was causing the effect.
Professor Jim Hughes, a genetics expert who co-lead the study, said: ‘The reason this has proved so difficult to work out, is that the previously identified genetic signal affects the ‘dark matter’ of the genome.
‘We found that the increased risk is not because of a difference in gene coding for a protein, but because of a difference in the DNA that makes a switch to turn a gene on.
‘It’s much harder to detect the gene which is affected by this kind of indirect switch effect.’
The team used a newly-developed, highly accurate technique to analyse people’s DNA and pinpoint the exact gene behind the effect.
LZTFL1 was found to cause more severe disease by blocking a protein that allows the lungs to fight off the virus.
It makes it easier for the virus to enter the lung cells and multiply, causing them to deteriorate.
The fact the gene works in this way means it has no impact on how well vaccines protect people against Covid, the researchers said.
Scientists had feared the gene was impacting people’s immune systems, which could have meant jabs would not work as well on them.
Professor James Davies, one of the co-leads of the study, told a press briefing: ‘If this gene hit the immune system, you would be really worried that people with this genotype would not respond to the vaccine.
‘The way this gene affects the lung is a completely different mechanism to the way the vaccine works against the virus.
‘The effect is in the biology of the lungs, which means people with the higher risk version of the gene should respond fully to vaccination.’
He added: ‘The higher risk DNA code is found more commonly in some black and minority ethnic communities but not in others.
‘Socioeconomic factors are also likely to be important in explaining why some communities have been particularly badly affected by the Covid pandemic.
‘Although we cannot change our genetics, our results show that the people with the higher risk gene are likely to particularly benefit from vaccination.
‘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.’
Dr Raghib Ali, an infectious disease expert at the University of Cambridge, said the discovery of the gene has helped understanding of why death rates have been so high in South Asian communities.
But Dr Ali, who is also an independent adviser on Covid and ethnicity to the Race Disparity Unit in the Cabinet Office, said it was important not to brush over other factors, including deprivation.
But he added: ‘There has been an unexplained residual excess risk in South Asians even after taking these risk factors into account.
‘Other studies have also shown that South Asians and Bangladeshis in particular — but not black groups — have worse survival than whites.
‘This study, as well as others, show that this may be due to them being more likely to carry this gene which increases their risk of death once infected.
‘Vaccine uptake has been high in South Asian groups but this study reinforces the importance of taking the booster doses now to maximise their protection and reduce their risk as immunity is now waning.’