Public health experts around the world are grappling with the question of why minority ethnic people appear more likely to become victims of Covid-19, but there are few signs the answers will come quickly.
UK authorities have started tracking cases by ethnicity to try to understand the reasons behind the apparent disparity. The government has ordered a review led by a public health expert.
The numbers are most marked within the country's state-run health service and social services, where the deaths of more than 100 workers and shortages of protective equipment have put the government under pressure to respond.
Nearly two thirds of deaths from fatalities within the health service are from black, Asian or minority ethnic backgrounds, an analysis published by the Health Service Journal shows.
Only one in five workers in the National Health Service are from the ethnic minorities, it said.
Other research suggests that ethnic minorities in the UK are worse hit than other sections of the population but the figures are less stark than among healthcare workers.
Hospital data from intensive care units in England, Wales and Northern Ireland suggests that 34 per cent of the most seriously ill were from those backgrounds.
UK census data from 2011 suggests that these minorities only make up 14 per cent of the population in England and Wales.
“Initial reports suggest there could be a disproportionate impact of Covid-19 on black, Asian and minority ethnic groups, in particular health and care professionals and other key workers,” said the UK’s Chief Medical Officer, Prof Chris Whitty.
The question of why has yet to be answered.
The illness is already known to have a disproportionately large impact on men and the elderly.
British authorities have called for researchers to propose new studies on ethnicity by May 11 to fill the gap in data.
A study published by The Lancet last week found that none of the 10 countries with the highest numbers of Covid-19 cases reported data related to ethnicity.
Researchers led by Manish Pareek, from the department of respiratory sciences at the University of Leicester, said the omission seemed stark in the UK, given the high numbers of health service deaths.
“If ethnicity is found to be associated with adverse Covid-19 outcomes, this must directly, and urgently, inform public health interventions globally,” their research said.
Researchers suggest there may be several factors including genetic, cultural and religious differences and environmental issues.
Some ethnic groups are known to be at greater risks of some diseases, such as diabetes and heart problems, which put them at risk of dying from Covid-19.
One consultancy brought in to advise public health experts has highlighted flaws in some of the key theories to explain the differences in death rates between communities.
Trevor Phillips, the former head of an equalities body who is on the UK government’s advisory panel, said there was “little reliable” information on the topic.
The rudimentary data showed that 13 of 17 Covid-19 hotspots had higher than average numbers of non-white residents.
Yet he cited the comparatively low level of coronavirus infections in Tower Hamlets, a London borough with the highest proportion of Pakistani and Bangladeshi Muslim residents.
It compared with high rates of infection in some areas where minorities were dominated by those of Indian descent.
Mr Phillips was criticised by some MPs for airing one theory that repeated handwashing before prayers among Muslim communities could have decreased the risk from coronavirus infection.
He also raised the question of whether some groups were more at risk because their jobs put them in greater danger, such as Indian doctors or ethnic minority bus drivers.
About half of transport staff in London are white and 26 per cent from black and ethnic minority backgrounds, says a 2018 report by their employer, Transport for London.
It confirmed on Wednesday that 35 transport staff had died from Covid-19.
The death rate, one for every 800 employees, is three times that of the general population, government figures show.
The Nuffield Trust health think tank suggested that the differences in deaths between ethnic groups was not so stark as the figures suggested.
Cases are greater in the country’s two biggest cities, London and Birmingham, which have higher rates of ethnic minorities. Forty per cent of Londoners have those backgrounds.
When the trust carried out analysis to reflect the uneven distribution of cases, “the apparent excess [ethnic] deaths due to Covid-19 disappears", researchers Theo Georghiou and John Appleby wrote in a blog.