Black people in the United States were making slight progress towards equality, but even that is being undone by the economic and social impacts of the coronavirus, according to an index of American equality released on Thursday.

Research by the National Urban League, a civil rights organization, found Black Americans' levels of equality with white people had risen slightly since 2018, aided by improvements in health and social justice.

But the calculations were made before the outbreak of COVID-19, which is wiping out Black gains in wealth and jobs, while killing about twice as many Black people as white, said the National Urban League report, "2020 State of Black America".

On a scorecard gauged with white people at 100%, Black Americans scored 74% on economics, health, education, social justice and civic engagement, up 1.6 percentage points from 2018, the League said.

Since those calculations were made, the United States has grappled with the impact of the pandemic and the Black Lives Matter movement, which was sparked in large part by the death of George Floyd, a Black man, in police custody.

"America is in crisis. Black America is in a doubly difficult crisis," said Marc Morial, National Urban League president.

"You've got the health issues related to COVID and the disproportionality of deaths and disease, and you've got the economic fallout, disproportionality in terms of unemployment, the impact on businesses.

"The you've got the racial justice crisis, which was put into plain sight by the death of George Floyd," he told the Thomson Reuters Foundation in an interview.

Even before the coronavirus and the economic recession, the study's findings "reflect longstanding racial and ethnic disparities across nearly every area of American life," the report said.