The analysis, conducted by government agency Public Health England (PHE), found that people of Bangladeshi heritage who tested positive for the virus were around twice as likely to die as their white British peers.
People from other minority communities, including those of Chinese, Indian, Pakistani and Caribbean descent, also had a 10% to 50% higher risk of death when compared to white Britons, the report found.
Those from black ethnic groups were also more likely to be diagnosed with Covid-19. The diagnosis rate per 100,000 of the population was 486 for black females and 649 for black males, compared to 220 for white females and 224 for white males.
The document was published Tuesday -- after the UK government denied British media reports that its release had been delayed due to protests in the US over the killing of George Floyd.
Commissioned by England's Chief Medical Officer Chris Whitty in April, amid fears the coronavirus pandemic was "disproportionately" affecting black and ethnic minority communities, the analysis was due to be published at the end of May, according to PHE.
In response to questions from CNN on Tuesday morning about why the report had been delayed, a government health department spokesperson said: "Ministers received initial findings yesterday [Monday]. They are being rapidly considered and a report will be published this week."
"It is not true to say this has been delayed due to global events," the spokesperson added.
In an address to parliament later Tuesday, UK Health Secretary Matt Hancock said: "Being black or from a minority ethnic background is a major [Covid-19] risk factor."
Hancock admitted that there was "much more work to do to understand the key drivers of these disparities, the relationships between the different risk factors and what we can do to close the gap."
The health secretary said he was "determined that we continue to develop our understanding and shape our response."
Hancock also stressed that the report did not just look at ethnicity but also found that age was the biggest Covid-19 risk factor, with older patients more likely to die than younger ones.
Among those who tested positive for the virus, those over 80 years old were deemed 70 times more likely to die than those under 40.
Combination of factors
The PHE analysis found that the link between ethnicity and health was "complex and likely to be the result of a combination of factors."
"Firstly, people of BAME [Black and minority ethnic] communities are likely to be at increased risk of acquiring the infection," it states.
"This is because BAME people are more likely to live in urban areas, in overcrowded households, in deprived areas, and have jobs that expose them to higher risk."
"People of BAME groups are also more likely than people of white British ethnicity to be born abroad, which means they may face additional barriers in accessing services that are created by, for example, cultural and language differences," it added.
The groups are "also likely to be at increased risk of poorer outcomes once they acquire the infection," the agency's report found.
"For example, some co-morbidities [the simultaneous presence of two diseases or conditions in a patient] which increase the risk of poorer outcomes from Covid-19 are more common among certain ethnic groups."
"People of Bangladeshi and Pakistani background have higher rates of cardiovascular disease than people from white British ethnicity, and people of black Caribbean and black African ethnicity have higher rates of hypertension compared with other ethnic groups," the report said.
The PHE analysis looked at the effect of sex, age, deprivation and region on survival among confirmed Covid-19 cases, but did not account for the effect of occupation, obesity or co-morbidities.
Its publication came as UN High Commissioner for Human Rights Michelle Bachelet warned that Covid-19 had exposed inequalities within society and was having a major disproportionate impact on racial and ethnic minorities, including people of African descent.
"The data tells us of a devastating impact from Covid-19 on people of African descent, as well as ethnic minorities in some countries, including Brazil, France, the United Kingdom and the United States," Bachelet said.
"In many other places, we expect similar patterns are occurring, but we are unable to say for sure given that data by race and ethnicity is simply not being collected or reported," she added.