After testing positive for COVID-19, superstar actor Idris Elba, who's built a career playing tough, streetwise characters like Baltimore gangster Stringer Bell, went online to set the record straight: Your skin color, he warned, won't protect you from the coronavirus.

"Black people, please, please, please understand that coronavirus, you can get it," Elba said, trying to quash a rumor swirling through cyberspace. "There are so many stupid, ridiculous conspiracy theories about black people not being able to get it. That's dumb, stupid. All right? That is the quickest way to get more black people killed."

Some U.S. physicians and researchers who study the intersection of race and health are joining Elba in sounding the alarm: The highly contagious and potentially deadly virus sweeping across the country is going to hit hard in the black community. And the reasons will reach beyond dangerous rumor-mongering and racially based misinformation.

The documented health disparities between racial groups in the U.S. – including higher rates of chronic diseases and lower access to health care among blacks compared with whites – make some African Americans more vulnerable to COVID-19, experts warn.

At the same time, more insidious problems, such as hidden biases white doctors have toward black patients, and black Americans' historical mistrust of the medical system, could exacerbate an already bad situation, accelerating transmission of the virus in struggling communities.

"I expect the COVID-19 pandemic to impact African Americans to a greater extent than other more socially advantaged groups," says Dr. Lisa Cooper, an internist and social epidemiologist with the Johns Hopkins Bloomberg School of Public Health. "This is because as a group, African Americans in the U.S. have higher rates of poverty, housing and food insecurity, unemployment or underemployment, and chronic medical conditions, and disabilities."

Meanwhile, as cases in the U.S. continue to mount – surpassing 55,000 and topping 800 deaths as of Wednesday, according to a Johns Hopkins University COVID-19 tracker – some doctors are calling on the Centers for Disease Control and Prevention and the World Health Organization to release data that could indicate whether the nationwide shortage of coronavirus tests is leaving black communities further behind. Current CDC testing data does not include a demographic breakdown.

In the U.S., "there are great discrepancies in not only the diagnosis but the treatment that African Americans and other minorities are afforded," Dr. Ebony Hilton, an associate professor of anesthesiology and critical care medicine at the University of Virginia, told Buzzfeed News. "So I want to make sure that in this pandemic, that black and brown people are treated in the same way and that these tests are made 
available in the same pattern as for white people."

The concern that black communities presently hampered by health 
inequities could be devastated by the coronavirus is rooted in decades of research as well as the nation's checkered racial history.

African Americans suffer from higher rates of conditions like asthma, obesity, diabetes and kidney disease – problems that experts say could make COVID-19 more damaging if they get it.

African Americans "also have less access to health insurance and paid sick leave, and poorer access to quality health care," Cooper notes. Research indicates African Americans are more likely than whites to rely on hospital emergency rooms for primary care – departments that soon may be overwhelmed with anticipated surges of COVID-19 patients.

What's more, because many black Americans hold hourly, low-wage jobs, "fear of lost wages or loss of employment may lead African Americans and other vulnerable Americans to try to work when they are ill, contributing to further spread of the disease within their communities," Cooper says.

Melody Goodman, associate dean for research at the New York University School of Global Public Health, says the potential impact will go beyond sick leave and time off.

"It is projected that post-coronavirus unemployment rates may hit 20%. Which groups are most likely to lose their jobs?" says Goodman, who also teaches biostatistics at NYU.

The country, she says, also "still has a high degree of residential segregation by race, ethnicity and socioeconomic status. That means many African Americans live in communities with subpar social determinants of health, including struggling education systems, scarce access to healthy food and a dearth of places to safely get outside and exercise or enjoy nature.

Such problems stand to be magnified in light of the coronavirus crisis, which Goodman says already "is demonstrating our country's lack of investment in public health and the fundamental public health 
infrastructure."

"If supermarkets and pharmacies are the only places to stay open, what happens if your community doesn't have either one of these businesses?" she asks. "What happens to the people with chronic conditions who are already living check to check? Can they really afford to stock up on food and medication? For people in households where toilet tissue was already a major household expense, what happens when the prices go up because there is limited supply? How do you socially distance, self-isolate or even quarantine if you live in a house with several other people?"

Then there's the social and cultural divide between African Americans and the predominantly white medical system. Researchers have found that some white doctors have a subconscious bias against black patients, likely fueling poor health outcomes and persistent racial disparities.

Cooper says African Americans' historic mistrust of the health system – fomented in part by the notorious Tuskegee experiment, the secret harvesting of cells from cancer patient Henrietta Lacks and segregated, unequal medical treatment during the Jim Crow era – can lead them to avoid seeking care, even though they may need it to avoid spreading the virus or becoming seriously ill.

The mistrust, Cooper says, can lead some to "ignore the advice of public health professionals who recommend practices such as social distancing and self-quarantining behaviors, thus worsening the impact of the 
epidemic on our community."

Also exacerbating the situation: a lack of minority doctors, says Gail Christopher, executive director of the National Collaborative for Health Equity.

As the crisis grinds on, front-line physicians "are having to decide who gets treated and who doesn't," Christopher says. "That's where the shadow of racial hierarchy and racial bias can come into play. Their decisions will be influenced by the shadow that we all live with, but we don't have the systems in place" to combat it.That, she says, "adds to the vulnerability" of black communities.

Still, Cooper says the only thing scientists truly know is how easily the virus is transmitted; there's limited data about COVID-19, as well as huge knowledge gaps about whether it affects black patients differently and how high the transmission rates are in black communities.

That lack of information – coupled with the federal government's 
stumbling, inconsistent response to the crisis – has created conditions ripe for misinformation, fueling the transmission of race-based rumors like the one Elba confronted.

"It's not unusual for myths and misinformation to be associated with a health crisis, particularly a pandemic, particularly one that didn't start here," Cooper says. And "it's not unusual for these myths to take on racial overtones," especially with a new virus that can be unpredictable.

Cooper, Christopher, Goodman and others agree that the coronavirus outbreak will expose the racial fault lines in the U.S. health care system, but it could also present an opportunity to bridge the gaps. They say the federal government should focus at least part of its massive relief and economic stimulus efforts on shoring up community health care systems, tackling generational disparities between African Americans and whites, and clearly communicating the dangers of the virus to the black community. Notably, the Trump administration this week said it had awarded $100 million to health centers across the country to help them cope with COVID-19.

The messaging, meanwhile, "should take into consideration the specific concerns and fears that may be prevalent in the community," Cooper says. 
"The communication should be frequent, clear, transparent and credible. The messages should convey empathy and respect for the wisdom and experience that exists within these communities. Specific falsehoods should be corrected."