Chibuzo Enemchukwu
Photograph by Frank Veronsky

Becoming a scientist

Chibuzo Enemchukwu

How can medical advances be extended to those who need them most? An infectious disease doctor adds molecular virology and social psychology to her repertoire.

By Alexandra MacWade

She is comfortable with long silences. “It’s okay to sit and wait,” she says. And if she breaks the silence, it may seem like she’s just changing the subject. But it is in these moments, when she gently guides the conversation elsewhere, that Chibuzo Enemchukwu often reaches a diagnosis. With her, questions like “What are your symptoms?” and “How long have you had them?” aren’t as important as: “Where are you from?” “What do you enjoy doing?” and “Tell me about your family.”

Enemchukwu, an infectious disease doctor, has always been fascinated by people and driven to do work that helps others. As a fellow in Rockefeller’s Clinical Scholars Program, she splits her time between twin pursuits at two locations: In virologist Charles M. Rice’s lab at Rockefeller, she’s working to understand why certain people develop severe reactions to the yellow fever vaccine. In Sarit Golub’s lab at Hunter College, a few blocks away, she conducts social psychology research, seeking to improve HIV prevention within sexual, gender, and ethnic minority communities.

Merging virology and social psychology is unusual, but it doesn’t seem strange to Enemchukwu, who was a psychology major at Duke University. As an undergraduate, she thought she might become a psychiatrist until her coursework nudged her in different directions—she took courses in social medicine that got her interested in health disparities across ethnic communities, and was then drawn to infectious disease. Both topics eventually inspired her to earn her medical degree, from the University of North Carolina.

And in fact, Enemchukwu’s current projects are not as different as they may seem. Fundamentally, both ask how a patient’s characteristics—genetic or social—can lead to vastly different outcomes. In the context of yellow fever, Enemchukwu seeks to understand why in rare cases, a person may develop a life-threatening reaction to the vaccine. And in her HIV project, she focuses on a disease-prevention strategy called pre-exposure prophylaxis, or PrEP, trying to get to the bottom of why its prescription and use is subject to racial and ethnic disparities.

“Ultimately, we are asking the same question,” she says. “How does who you are affect your health?”

Since it became available five years ago, PrEP has been prescribed to tens of thousands of Americans at risk of contracting HIV. A pill sold under the brand name Truvada, it stops the virus from replicating and establishing itself in the body. When used correctly—it must be taken daily, and patients need to see their doctor for follow-ups—it is more than 90 percent effective.

Yet even as more and more prescriptions are being filled, health experts worry that the drug is not living up to its promise. Data shows that black people fill as little as 10 to 12 percent of all Truvada prescriptions, despite the fact that 44 percent of people receiving their first HIV diagnosis are black. Within both black and white communities, most new HIV diagnoses occur in men who have sex with other men (many but not all of whom identify as gay or as belonging to another sexual minority group).

“What we’re seeing is that the people who need PrEP the most aren’t on it,” Enemchukwu says. “We have an HIV epidemic that disproportionately affects black men who have sex with other men, and we have this great drug that these populations aren’t taking.”

A simple answer would be that black men who have sex with men don’t want PrEP. But that’s not usually the case, Enemchukwu has learned: when these men are offered the drug, most are in fact interested in taking it. Instead, she and others have found that stigma plays a big role, as does the fact that those who would benefit most from the regimen have limited access to it, due to lower rates of health insurance coverage or difficulty accessing the healthcare system in general.

“HIV stigma is real, as is gay stigma, particularly in black communities,” Enemchukwu says. “Studies have shown that black patients are often more reluctant to disclose they’re gay. If you’re not ‘out’ in that sense, you won’t be going to an LGBTQ center, and that’s historically where the drug has been prescribed the most.” Many community-based primary care clinics—which some ethnic minorities are more likely to rely on—lack either the resources or the expertise to provide it.

In researching PrEP use, Enemchukwu has learned that there is also stigma and misinformation surrounding the medication itself, and in some cases it is being perpetuated by doctors. Evidence suggests that if you’re a man who has sex with other men, your doctor will be less likely to prescribe PrEP if you’re black than if you’re white. Many assume that the reason rates of HIV infection are skyrocketing in some black communities is because black men tend to lead more promiscuous sex lives. But studies show the opposite: that high-risk black men have fewer sex partners and are more likely to use condoms than their white counterparts.
The research points to another factor: that your likelihood of encountering someone who’s HIV-positive is simply higher if you’re a black man. “It’s about probabilities and social networks,” Enemchukwu says.

In one of her projects, Enemchukwu is working with Golub and the New York City Department of Health to study PrEP implementation in the city’s clinics. They are looking at ways to make the drug accessible to everyone who needs it, and to ensure that providers have the tools they need to prescribe it.

“I want to take evidence and learn how to turn it into action. Here, the root of that idea is in every lab.”

The most challenging roadblock, she says, is changing prevalent attitudes about who should and should not be on PrEP. “We have to find a way to convince both providers and the public that it’s time to drop all preconceived notions about black gay men and PrEP users in general. Prescribing someone PrEP will not encourage irresponsible sexual behavior—it will simply offer an effective means of protection to the most vulnerable.”

Enemchukwu was born in Boston and grew up in central Florida, near Orlando. Her parents are from the same town in Nigeria but didn’t meet until they were both in Boston studying to be pharmacists. When Enemchukwu was young, they would take her and her five siblings to visit her grandparents in their home country. She was struck by how many people, not just her relatives, would come to her grandparents’ house when they learned that family from America was visiting.

“We’d bring tons of suitcases with us, packed full of medicine, shoes, clothes to give away,” she says. The visitors would often stay to talk, finding comfort in telling Enemchukwu’s family their problems.

Years after her childhood trips to Nigeria, Enemchukwu again found herself listening to similar stories. She took a leave of absence after her third year of medical school to join Karibu, a nonprofit organization based in Madrid that provides medical and other services to Sub-Saharan African immigrants. The work touched on a theme that interested her, particularly in light of her parents’ immigration to the U.S.—her attention was rapt each time someone spoke about what it had been like to leave their home and go someplace else to make a better life. The conversations were often challenging, and there were vast cultural divides between her and some of her patients, not to mention language barriers. The experience turned out to be invaluable.

In medical school, Enemchukwu had learned the basics of bedside manner: she and her fellow students were taught not only to sit when they interacted with patients, but to sit lower than their patients to appear less intimidating. They were told to make eye contact, and they learned how to clearly explain diagnoses and complicated procedures. From her sunken chair, Enemchukwu took great care to make eye contact with the immigrant patients she met in Madrid, but she also began developing her own style. For starters, she allowed long pauses to elapse in the conversation, and she figured out the kinds of questions she should be asking.

Many of the people she saw at Karibu complained of pain: back pain, shoulder pain, headaches. “I came to realize that many of these symptoms were physical manifestations of depression and stress,” she says, “which is not unusual in immigrant communities.” Her questions turned to the more essential: “Where are you sleeping at night?” “Are you getting enough food to eat?” and “Do you have work?”

Enemchukwu completed her fellowship in infectious disease at the Albert Einstein College of Medicine, and did a significant part of her clinical work at the Jacobi Medical Center in the Bronx, one of the poorest and most diverse places in the country and one greatly affected by HIV. At the end of her fellowship, she took another trip abroad, this time to Malawi for a month to help with a study on HIV and malaria. In the hospital where she worked, most of the adult patients she saw in the general wards had end-stage AIDS. It was emotionally overwhelming, and she was heartbroken to see how the modern healthcare she had been trained to deliver was glaringly absent from a part of the world where it was critically needed.

“The trip was absolutely life-changing,” she says. “When I came back, I was motivated to do something. I had to do something.” She thought about traveling to Malawi or other places for a few months every year while continuing to work as an infectious disease doctor in the U.S., but that “would have been putting a small Band-Aid on a gaping wound, and would really just have been a way of making myself feel better,” she says. Instead, she applied to be a clinical scholar, and join a rigorous multiyear training program in which clinicians add to their medical degree a master’s in clinical and translational research.

She liked that the program would prepare her for a career in patient-oriented research, and that she could create her own curriculum. But there was more: “I don’t want to do research for the sake of doing research,” she says. “I want to take evidence and learn how to turn it into action. At Rockefeller, the root of that idea is in every lab.”

Before working with Rice on a project to understand life-threatening reactions to the yellow fever vaccine, Enemchukwu hadn’t set foot in a basic science lab. “I made a lot of mistakes running experiments,” she says, “but I learned a lot.”

Chibuzo Enemchukwu
Chibuzo Enemchukwu

Like PrEP, the yellow fever vaccine is highly effective. With one dose, most people will be fully protected against the virus for life. But Enemchukwu and Rice are focusing on a small fraction of patients—four out of every million—who will develop severe reactions to the vaccine. Most of them have neurotropic disease, an illness resembling brain inflammation, which is severe but not usually life threatening. Others develop viscerotropic disease, which is similar to the yellow fever disease itself, and devastating—these patients, who may suffer from liver or kidney dysfunction, bleeding, and fever, rarely survive.

The Rice lab has shown that these fatal reactions are likely caused by a defect in the immune system. Together with collaborators in Brazil, where there was recently a yellow fever epidemic and a mass vaccination campaign, Enemchukwu has helped acquire tissue samples from viscerotropic disease patients. The lab is now trying to pinpoint what genes may be driving the condition and how the vaccine’s viral component interacts with an infected person’s cells.

Enemchukwu is beginning to understand the amount of meticulous work it takes to move basic science projects forward. “Working in the clinic, I didn’t fully appreciate all the challenges involved in getting new drugs to patients,” she says. Rice himself can attest to the Sisyphean aspect of the effort: it took him 30 years to replicate the virus that causes hepatitis C, a discovery that ultimately led to a cure for that disease.

“There are several barriers with this project, too,” Enemchukwu says, “including finding the tissue samples, which are extremely hard to come by. Once we have them, we hope that our experiments will work. And once we get the results, we hope they will put us on the right track.”

Her vision is that this work will help create methods to screen people with an increased risk for developing severe reactions—including the elderly, infants, and those with certain autoimmune diseases—before they are vaccinated against yellow fever.

Enemchukwu is a little more than a third of the way through the Clinical Scholars Program, and for the first time in her life, she doesn’t have a clear idea of what her next steps will be. “It’s both distressing and refreshing,” she says. She knows that she would like to start a research career that combines her interests in infectious diseases, minority and immigrant populations, and health disparities. And she is interested in collaborating on global health projects and continuing her work on HIV.

“I also know that I want to see patients, and I want to teach medical students and residents,” she says. “Those things I know. But other than that?” She takes a long pause and smiles. “That’s TBD.”