BAME: Genetic variation ‘unlikely to influence Covid-19 mortality’

Black, Asian, and minority ethnic (BAME) people are not genetically more at-risk of dying from Covid-19, a new study has concluded.  

Scientists in Japan and the US found no differences in seven genes associated with viral entry of SARS-CoV-2 – the virus that causes Covid-19 – across ethnic groups.

Pre-existing medical conditions and environmental factors are more likely to blame for people of ethnic minorities being more likely to die of the disease, they say.  

BAME communities are two to three times more likely to die from coronavirus than other members of the population, it was previously revealed, based on analysis of NHS data.

Public Health England also reported the mortality rate – the number of people dying with the coronavirus out of each 100,000 people – is more than three times as high for black men than other groups. 

Although BAME people are not considered genetically more at risk of Covid-19, it’s been suggested minority ethnic people have had less access to medical resources during the pandemic and live in densely populated areas, causing fast transmission. 

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‘Morbidity and mortality vary significantly around the globe between populations and ethnic groups,’ the researchers say in Infection, Genetics and Evolution. 

‘Disproportionately high incidence and mortality rates in African Americans in the US could be due to non-genetic factors.’

The team admit that a genetic predisposition may play a role for severe cases with respiratory failure, which is one of the main symptoms of Covid-19. 

African Americans in the US and ethnic minorities in the UK are disproportionately affected by Covid-19.  

BAME people are more likely to develop severe symptoms and also show higher mortality compared with other regional and ethnic groups. 

To investigate if this disparity could be caused by genetic variation, the team of researchers from Harvard University and Hokkaido University in Japan surveyed publicly available databases of genomic variants.

They used gnomAD, the Korean Reference Genome Database, TogoVar, a Japanese genetic variation database, and the 1000 Genomes Project – all adding up to thousands of individuals. 

They studied variants across multiple regional and ethnic groups in seven genes known to play roles in viral entry into host cells and recognition of viral RNA in host cells. 

Coronaviruses belong to the class of ‘enveloped viruses’, meaning they are covered by a fatty layer. 

SARS-CoV-2 has spiked protein (S protein) on its envelope, which allows it to bind with the ACE2 receptor on the cell surface, which allows it access to human cells.  

ACE2, which is attached to membranes of cells located in the lungs, heart and other organs, has already been found to be the ‘gateway’ for coronavirus infection.

It is then broken into two pieces by the enzymes TMPRSS2 and cathepsin B and L.

After the virus enters the cells, the viral RNA binds with proteins such as TLR3, TLR7 and TLR8, triggering an innate immune response. 

The researchers found genetic variants in these seven proteins, with the largest number of variants in ACE2 receptor. 

However, very few of these variations alter the functions of these proteins, they found. 

Since the overall variation frequency was extremely low (less than 0.01 percent), the scientists determined there is no significant difference across populations or ethnic groups in the functions of the seven proteins involved in infection. 

Differences in morbidity and mortality are not the result of genetic variations in genes for viral entry across populations, they have concluded. 

Pre-existing medical conditions, individual medical histories, environmental factors and healthcare disparities, likely play a bigger role in death rates.  

The main databases used in the study were also mostly representing Asian populations – for example, gnomAD consists of 1,909 Korean, 76 Japanese, and 7,212 other east Asian individuals.  

The team also pointed out that a previous study from June found genetic factors may contribute to serious cases of Covid-19.  

Earlier this year, University College London researchers found the average risk of dying in hospital from Covid-19 was around two to three times higher for BAME groups in in England, when compared to the general population.    

The study, published in Wellcome Open Research, used NHS data on age, region and ethnicity from patients with a positive Covid-19 test who later died in hospital. 

Adjusting for age and region, the risk of death from Covid-19 for Black African groups was 3.24 times higher than the general population, they found.

Pakistani people had a 3.29 times higher risk, Bangladeshi 2.41 times higher, Black Caribbean 2.21 times higher and Indian 1.7 times.

Another report from May found black people in England are 3.4 times more likely to test positive for Covid-19 than people from white British backgrounds. 

This study, based on data from nearly 400,000 participants in the UK Biobank database, also found South Asian people were 2.4 times more likely to have a positive test. 

The study authors said socio-economic differences, such as finances and access to resources, are likely key to the findings.

‘There is unlikely to be a single factor underlying these differences,’ Dr. S Vittal Katikireddi at the Institute of Health and Wellbeing at the University of Glasgow told MailOnline at the time. 

‘I think an important part of the picture is socioeconomic differences – some ethnic groups are worse off financially and have less access to resources.’  

Ethnic minorities were also more likely to receive their diagnosis in a hospital setting, which suggests they were more severely impacted by Covid-19. 

‘One possibility that remains is that some ethnic and socioeconomic groups have a poorer prognosis and are therefore more likely to be admitted to hospital and therefore to be tested,’ the authors said. 

Black and Asian people may be more likely to die of Covid-19 in England and Wales because many of them live in polluted areas, according to another report from August. 

The Office for National Statistics (ONS) said it found a 7 per cent increase in the risk of dying of coronavirus in England’s most polluted areas.

As the percentage BAME people making up the population of a region increased, so did the exposure to nitrogen dioxide (NO2), they found.

NO2 causes respiratory symptoms such as shortness of breath, inflames the lining of the lungs and reduces immunity to lung infections such as bronchitis.  

Air pollution is one of many factors that may be driving disproportionate outcomes for BAME people and scientists said it was ‘very plausible that higher exposure to air pollution will be a contributory factor’. 

It’s possible minority ethnic people are poorer and therefore in worse health, and more likely to work in public-facing jobs where they are more likely to catch the illness.