Why Neglected Tropical Diseases Should Matter to Americans
Daisy Hernández was five years old when one of her favorite aunts was struck with a mysterious illness. Tía Dora had stayed behind in Colombia when Daisy's mother immigrated to Union City, New Jersey. A schoolteacher in her late 20s, she began suffering from fevers and abdominal pain, and her belly grew so big that people thought she was pregnant. Exploratory surgery revealed that her large intestine had swollen to ten times its normal size, and she was fitted with a colostomy bag. Doctors couldn't identify the underlying problem—but whatever it was, they said, it would likely kill her within a year or two.
Tía Dora's sisters in New Jersey—Hernández's mother and two other aunts—weren't about to let that happen. They pooled their savings and flew her to New York City, where a doctor at Columbia-Presbyterian Medical Center with a penchant for obscure ailments provided a diagnosis: Chagas disease. Transmitted by the bite of triatomine insects, commonly known as kissing bugs, Chagas is endemic in many parts of Latin America. It's caused by the parasite Trypanoma cruzi, which usually settles in the heart, where it feeds on muscle tissue. In some cases, however, it attacks the intestines or esophagus. Tía Dora belonged to that minority.
In 1980, U.S. immigration laws were more forgiving than they are today. Tía Dora was able to have surgery to remove a part of her colon, despite not being a citizen or having a green card. She eventually married a legal resident and began teaching Spanish at an elementary school. Over the next three decades, she earned a graduate degree, built a career, and was widowed. Meanwhile, Chagas continued its slow devastation. "Every couple of years, we were back in the hospital with her," Hernández recalls. "When I was in high school, she started feeling like she couldn't swallow anything. It was the parasite, destroying the muscles of her esophagus."
When Tía Dora died in 2010, at 59, her niece was among the family members at her bedside. By then, Hernández had become a journalist and fiction writer. Researching a short story about Chagas disease, she discovered that it affected an estimated 6 million people in South America, Central America, and Mexico—as well as 300,000 in the United States, most of whom were immigrants from those places. "I was shocked to learn it wasn't rare," she says. "That made me hungry to know more about this disease, and about the families grappling with it."
Hernández's curiosity led her to write The Kissing Bug, a lyrical hybrid of memoir and science reporting that was published in June. It also led her to another revelation: Chagas is not unique. It's among the many maladies that global health experts refer to as neglected tropical diseases—often-disabling illnesses that afflict 1.7 billion people worldwide, while getting notably less attention than the "big three" of HIV/AIDs, malaria, and tuberculosis. NTDs cause fewer deaths than those plagues, but they wreak untold suffering and economic loss.
Shortly before Hernández's book hit the shelves, the World Health Organization released its 2021-2030 roadmap for fighting NTDs. The plan sets targets for controlling, eliminating, or eradicating all the diseases on the WHO's list, through measures ranging from developing vaccines to improving healthcare infrastructure, sanitation, and access to clean water. Experts agree that for the campaign to succeed, leadership from wealthy nations—particularly the United States—is essential. But given the inward turn of many such countries in recent years (evidenced in movements ranging from America First to Brexit), and the continuing urgency of the COVID-19 crisis, public support is far from guaranteed.
As Hernández writes: "It is easier to forget a disease that cannot be seen." NTDs primarily affect residents of distant lands. They kill only 80,000 people a year, down from 204,000 in 1990. So why should Americans to bother to look?
Breaking the circle of poverty and disease
The World Health Organization counts 20 diseases as NTDs. Along with Chagas, they include dengue and chikungunya, which cause high fevers and agonizing pain; elephantiasis, which deforms victims' limbs and genitals; onchocerciasis, which causes blindness; schistosomiasis, which can damage the heart, lungs, brain, and genitourinary system; helminths such as roundworm and whipworm, which cause anemia, stunted growth, and cognitive disabilities; and a dozen more. Such ailments often co-occur in the same patient, exacerbating each other's effects and those of illnesses such as malaria.
NTDs may be spread by insects, animals, soil, or tainted water; they may be parasitic, bacterial, viral, or—in the case of snakebite envenoming—non-infectious. What they have in common is their longtime neglect by public health agencies and philanthropies. In part, this reflects their typically low mortality rates. But the biggest factor is undoubtedly their disempowered patient populations.
"These diseases occur in the setting of poverty, and they cause poverty, because of their chronic and debilitating effects," observes Peter Hotez, dean of the National School of Tropical Medicine at Baylor University and co-director of the Texas Children's Hospital for Vaccine Development. And historically, the everyday miseries of impoverished people have seldom been a priority for those who set the global health agenda.
That began to change about 20 years ago, when Hotez and others developed the conceptual framework for NTDs and early proposals for combating them. The WHO released its first roadmap in 2012, targeting 17 NTDs for control, elimination, or eradication by 2020. (Rabies, snakebite, and dengue were added later.) Since then, the number of people at risk for NTDs has fallen by 600 million, and 42 countries have eliminated at least one such disease. Cases of dracunculiasis—known as Guinea worm disease, for the parasite that creates painful blisters in a patient's skin—have dropped from the millions to just 27 in 2020.
Yet the battle is not over, and the COVID-19 pandemic has disrupted prevention and treatment programs around the globe.
A new direction — and longstanding obstacles
The WHO's new roadmap sets even more ambitious goals for 2030. Among them: reducing by 90 percent the number of people requiring treatment for NTDs; eliminating at least one NTD in another 100 countries; and fully eradicating dracunculiasis and yaws, a disfiguring skin infection.
The plan also places an increased focus on "country ownership," relying on nations with high incidence of NTDs to design their own plans based on local expertise. "I was so excited to see that," says Kristina Talbert-Slagle, director of the Yale College Global Health Studies program. "No one is a better expert on how to address these situations than the people who deal with it day by day."
Another fresh approach is what the roadmap calls "cross-cutting" targets. "One of the really cool things about the plan is how much it emphasizes coordination among different sectors of the health system," says Claire Standley, a faculty member at Georgetown University's Center for Global Health Science and Security. "For example, it explicitly takes into account the zoonotic nature of many neglected tropical diseases—the fact that we have to think about animal health as well as human health when we tackle NTDs."
Whether this grand vision can be realized, however, will depend largely on funding—and that, in turn, is a question of political will in the countries most able to provide it. On the upside, the U.S. has ended its Trump-era feud with the WHO. "One thing that's been really encouraging," says Standley, "has been the strong commitment toward global cooperation from the current administration." Even under the previous president, the U.S. remained the single largest contributor to the global health kitty, spending over $100 million annually on NTDs—six times the figure in 2006, when such financing started.
On the downside, America's outlay has remained flat for several years, and the Biden administration has so far not moved to increase it. A "back-of-the-envelope calculation," says Hotez, suggests that the current level of aid could buy medications for the most common NTDs for about 200 million people a year. But the number of people who need treatment, he notes, is at least 750 million.
Up to now, the United Kingdom—long the world's second-most generous health aid donor—has taken up a large portion of the slack. But the UK last month announced deep cuts in its portfolio, eliminating 102 previously supported countries and leaving only 34. "That really concerns me," Hotez says.
The struggle for funds, he notes, is always harder for projects involving NTDs than for those aimed at higher-profile diseases. His lab, which he co-directs with microbiologist Maria Elena Bottazzi, started developing a COVID-19 vaccine soon after the pandemic struck, for example, and is now in Phase 3 trials. The team has been working on vaccines for Chagas, hookworm, and schistosomiasis for much longer, but trials for those potential game-changers lag behind. "We struggle to get the level of resources needed to move quickly," Hotez explains.
Two million reasons to care
One way to prompt a government to open its pocketbook is for voters to clamor for action. A longtime challenge with NTDs, however, has been getting people outside the hardest-hit countries to pay attention.
The reasons to care, global health experts argue, go beyond compassion. "When we have high NTD burden," says Talbert-Slagle, "it can prevent economic growth, prevent innovation, lead to more political instability." That, in turn, can lead to wars and mass migration, affecting economic and political events far beyond an affected country's borders.
Like Hernández's aunt Dora, many people driven out of NTD-wracked regions wind up living elsewhere. And that points to another reason to care about these diseases: Some of your neighbors might have them. In the U.S., up to 14 million people suffer from neglected parasitic infections—including 70,000 with Chagas in California alone.
When Hernández was researching The Kissing Bug, she worried that such statistics would provide ammunition to racists and xenophobes who claim that immigrants "bring disease" or exploit overburdened healthcare systems. (This may help explain some of the stigma around NTDs, which led Tía Dora to hide her condition from most people outside her family.) But as the book makes clear, these infections know no borders; they flourish wherever large numbers of people lack access to resources that most residents of rich countries take for granted.
Indeed, far from gaming U.S. healthcare systems, millions of low-income immigrants can't access them—or must wait until they're sick enough to go to an emergency room. Since Congress changed the rules in 1996, green card holders have to wait five years before they can enroll in Medicaid. Undocumented immigrants can never qualify.
Closing the great divide
Hernández uses a phrase borrowed from global health crusader Paul Farmer to describe this access gap: "the great epi divide." On one side, she explains, "people will die from cancer, from diabetes, from chronic illnesses later in life. On the other side of the epidemiological divide, people are dying because they can't get to the doctor, or they can't get medication. They don't have a hospital anywhere near them. When I read Dr. Farmer's work, I realized how much that applied to neglected diseases as well."
When it comes to Chagas disease, she says, the epi divide is embodied in the lack of a federal mandate for prenatal or newborn screening. Each year, according to the Centers for Disease Control and Prevention, up to 300 babies in the U.S. are born with Chagas, which can be passed from the mother in utero. The disease can be cured with medication if treated in infancy. (It can also be cured in adults in the acute stage, but is seldom detected in time.) Yet the CDC does not require screening for Chagas—even though newborns are tested for 15 diseases that are less common. According to one study, it would be 10 times cheaper to screen and treat babies and their mothers than to cover the costs related to the illness in later years. Few states make the effort.
The gap that enables NTDs to persist, Hernández argues, is the same one that has led to COVID-19 death rates in Black and Latinx communities that are double those elsewhere in America. To close it, she suggests, caring is not enough.
"When I was working on my book," she says, "I thought about HIV in the '80s, when it had so much stigma that no one wanted to talk about it. Then activists stepped up and changed the conversation. I thought a lot about breast cancer, which was stigmatized for years, until people stepped forward and started speaking out. I thought about Lyme disease. And it wasn't only patients—it was also allies, right? The same thing needs to happen with neglected diseases around the world. Allies need to step up and make demands on policymakers. We need to make some noise."
Blood Money: Paying for Convalescent Plasma to Treat COVID-19
Convalescent plasma – first used to treat diphtheria in 1890 – has been dusted off the shelf to treat COVID-19. Does it work? Should we rely strictly on the altruism of donors or should people be paid for it?
The biologic theory is that a person who has recovered from a disease has chemicals in their blood, most likely antibodies, that contributed to their recovery, and transferring those to a person who is sick might aid their recovery. Whole blood won't work because there are too few antibodies in a single unit of blood and the body can hold only so much of it.
Plasma comprises about 55 percent of whole blood and is what's left once you take out the red blood cells that carry oxygen and the white blood cells of the immune system. Most of it is water but the rest is a complex mix of fats, salts, signaling molecules and proteins produced by the immune system, including antibodies.
A process called apheresis circulates the donors' blood through a machine that separates out the desired parts of blood and returns the rest to the donor. It takes several times the length of a regular whole blood donation to cycle through enough blood for the process. The end product is a yellowish concentration called convalescent plasma.
Recent History
It was used extensively during the great influenza epidemic off 1918 but fell out of favor with the development of antibiotics. Still, whenever a new disease emerges – SARS, MERS, Ebola, even antibiotic-resistant bacteria – doctors turn to convalescent plasma, often as a stopgap until more effective antibiotic and antiviral drugs are developed. The process is certainly safe when standard procedures for handling blood products are followed, and historically it does seem to be beneficial in at least some patients if administered early enough in the disease.
With few good treatment options for COVID-19, doctors have given convalescent plasma to more than a hundred thousand Americans and tens of thousand of people elsewhere, to mixed results. Placebo-controlled trials could give a clearer picture of plasma's value but it is difficult to enroll patients facing possible death when the flip of a coin will determine who will receive a saline solution or plasma.
And the plasma itself isn't some uniform pill stamped out in a factory, it's a natural product that is shaped by the immune history of the donor's body and its encounter not just with SARS-CoV-2 but a lifetime of exposure to different pathogens.
Researchers believe antibodies in plasma are a key factor in directly fighting the virus. But the variety and quantity of antibodies vary from donor to donor, and even over time from the same donor because once the immune system has cleared the virus from the body, it stops putting out antibodies to fight the virus. Often the quality and quantity of antibodies being given to a patient are not measured, making it somewhat hit or miss, which is why several companies have recently developed monoclonal antibodies, a single type of antibody found in blood that is effective against SARS-CoV-2 and that is multiplied in the lab for use as therapy.
Plasma may also contain other unknown factors that contribute to fighting disease, say perhaps signaling molecules that affect gene expression, which might affect the movement of immune cells, their production of antiviral molecules, or the regulation of inflammation. The complexity and lack of standardization makes it difficult to evaluate what might be working or not with a convalescent plasma treatment. Thus researchers are left with few clues about how to make it more effective.
Industrializing Plasma
Many Americans living along the border with Mexico regularly head south to purchase prescription drugs at a significant discount. Less known is the medical traffic the other way, Mexicans who regularly head north to be paid for plasma donations, which are prohibited in their country; the U.S. allows payment for plasma donations but not whole blood. A typical payment is about $35 for a donation but the sudden demand for convalescent plasma from people who have recovered from COVID-19 commands a premium price, sometimes as high as $200. These donors are part of a fast-growing plasma industry that surpassed $25 billion in 2018. The U.S. supplies about three-quarters of the world's needs for plasma.
Payment for whole blood donation in the U.S. is prohibited, and while payment for plasma is allowed, there is a stigma attached to payment and much plasma is donated for free.
The pharmaceutical industry has shied away from natural products they cannot patent but they have identified simpler components from plasma, such as clotting factors and immunoglobulins, that have been turned into useful drugs from this raw material of plasma. While some companies have retooled to provide convalescent plasma to treat COVID-19, often paying those donors who have recovered a premium of several times the normal rate, most convalescent plasma has come as donations through traditional blood centers.
In April the Mayo Clinic, in cooperation with the FDA, created an expanded access program for convalescent plasma to treat COVID-19. It was meant to reduce the paperwork associated with gaining access to a treatment not yet approved by the FDA for that disease. Initially it was supposed to be for 5000 units but it quickly grew to more than twenty times that size. Michael Joyner, the head of the program, discussed that experience in an extended interview in September.
The Centers for Medicare and Medicaid Services (CMS) also created associated reimbursement codes, which became permanent in August.
Mayo published an analysis of the first 35,000 patients as a preprint in August. It concluded, "The relationships between mortality and both time to plasma transfusion, and antibody levels provide a signature that is consistent with efficacy for the use of convalescent plasma in the treatment of hospitalized COVID-19 patients."
It seemed to work best when given early in infection and in larger doses; a similar pattern has been seen in studies of monoclonal antibodies. A revised version will soon be published in a major medical journal. Some criticized the findings as not being from a randomized clinical trial.
Convalescent plasma is not the only intervention that seems to work better when used earlier in the course of disease. Recently the pharmaceutical company Eli Lilly stopped a clinical trial of a monoclonal antibody in hospitalized COVID-19 patients when it became apparent it wasn't helping. It is continuing trials for patients who are less sick and begin treatment earlier, as well as in persons who have been exposed to the virus but not yet diagnosed as infected, to see if it might prevent infection. In November the FDA eased access to this drug outside of clinical trials, though it is not yet approved for sale.
Show Me the Money
The antibodies that seem to give plasma its curative powers are fragile proteins that the body produces to fight the virus. Production shuts down once the virus is cleared and the remaining antibodies survive only for a few weeks before the levels fade. [Vaccines are used to train immune cells to produce antibodies and other defenses to respond to exposure to future pathogens.] So they can be usefully harvested from a recovered patient for only a few short weeks or months before they decline precipitously. The question becomes, how does one mobilize this resource in that short window of opportunity?
The program run by the Mayo Clinic explains the process and criteria for donating convalescent plasma for COVID-19, as well as links to local blood centers equipped to handle those free donations. Commercial plasma centers also are advertising and paying for donations.
A majority of countries prohibit paying donors for blood or blood products, including India. But an investigation by India Today touted a black market of people willing to donate convalescent plasma for the equivalent of several hundred dollars. Officials vowed to prosecute, saying donations should be selfless.
But that enforcement threat seemed to be undercut when the health minister of the state of Assam declared "plasma donors will get preference in several government schemes including the government job interview." It appeared to be a form of compensation that far surpassed simple cash.
The small city of Rexburg, Idaho, with a population a bit over 50,000, overwhelmingly Mormon and home to a campus of Brigham Young University, at one point had one of the highest per capita rates of COVID-19 in the current wave of infection. Rumors circulated that some students were intentionally trying to become infected so they could later sell their plasma for top dollar, potentially as much as $200 a visit.
Troubled university officials investigated the allegations but could come up with nothing definitive; how does one prove intentionality with such an omnipresent yet elusive virus? They chalked it up to idle chatter, perhaps an urban legend, which might be associated with alcohol use on some other campus.
Doctors, hospitals, and drug companies are all rightly praised for their altruism in the fight against COVID-19, but they also get paid. Payment for whole blood donation in the U.S. is prohibited, and while payment for plasma is allowed, there is a stigma attached to payment and much plasma is donated for free. "Why do we expect the donors [of convalescent plasma] to be the only uncompensated people in the process? It really makes no sense," argues Mark Yarborough, an ethicist at the UC Davis School of Medicine in Sacramento.
"When I was in grad school, two of my closest friends, at least once a week they went and gave plasma. That was their weekend spending money," Yarborough recalls. He says upper and middle-income people may have the luxury of donating blood products but prohibiting people from selling their plasma is a bit paternalistic and doesn't do anything to improve the economic status of poor people.
"Asking people to dedicate two hours a week for an entire year in exchange for cookies and milk is demonstrably asking too much," says Peter Jaworski, an ethicist who teaches at Georgetown University.
He notes that companies that pay plasma donors have much lower total costs than do operations that rely solely on uncompensated donations. The companies have to spend less to recruit and retain donors because they increase payments to encourage regular repeat donations. They are able to more rationally schedule visits to maximize use of expensive apheresis equipment and medical personnel used for the collection.
It seems that COVID-19 has been with us forever, but in reality it is less than a year. We have learned much over that short time, can now better manage the disease, and have lower mortality rates to prove it. Just how much convalescent plasma may have contributed to that remains an open question. Access to vaccines is months away for many people, and even then some people will continue to get sick. Given the lack of proven treatments, it makes sense to keep plasma as part of the mix, and not close the door to any legitimate means to obtain it.
Vaccines Without Vaccinations Won’t End the Pandemic
COVID-19 vaccine development has advanced at a record-setting pace, thanks to our nation's longstanding support for basic vaccine science coupled with massive public and private sector investments.
Yet, policymakers aren't according anywhere near the same level of priority to investments in the social, behavioral, and data science needed to better understand who and what influences vaccination decision-making. "If we want to be sure vaccines become vaccinations, this is exactly the kind of work that's urgently needed," says Dr. Bruce Gellin, President of Global Immunization at the Sabin Vaccine Institute.
Simply put: it's possible vaccines will remain in refrigerators and not be delivered to the arms of rolled-up sleeves if we don't quickly ramp up vaccine confidence research and broadly disseminate the findings.
According to the most recent Gallup poll, the share of U.S. adults who say they would get a COVID-19 vaccine rose to 58 percent this month from 50 percent in September, with non-white Americans and those ages 45-65 even less willing to be vaccinated. While there is still much we don't understand about COVID-19, we do know that without high levels of immunity in the population, a return to some semblance of normalcy is wishful thinking.
Research from prior vaccination campaigns such as H1N1, HPV, and the annual flu points us in the right direction. Key components of successful vaccination efforts require 1) Identifying the concerns of particular segments of the population; 2) Tailoring messages and incentives to address those concerns, and 3) Reaching out through trusted sources – health care providers, public health departments, and others in the community.
Research during the H1N1 flu found preparing people for some uncertainty actually improved trust, according to Dr. Sandra Crouse Quinn, professor and chair, Family Science, University of Maryland. Dr. Crouse Quinn's research during that period also underscored the need to address the specific vaccine concerns of racial and ethnic groups.
The stunning scientific achievement of COVID-19 vaccines anticipated to be ready in record time needs to be backed up by an equally ambitious and evidence-based effort to build the public's confidence in the vaccines.
Data science has provided crucial insight about the social media universe. Dr. Neil Johnson, a scientist at George Washington University, found that despite having fewer followers, anti-vaccination pages are more numerous and growing faster than pro-vaccination pages. They are more often linked to in discussions on other Facebook pages – such as school parent associations – where people are undecided about vaccination.
We've learned about building vaccine confidence from earlier campaigns. Now, however, we are faced with a unique and challenging set of obstacles to unpack quickly: How do we communicate the importance of eventual COVID-19 vaccines to Americans in light of the muddled-to-poor messaging from political leaders, the weaponizing of relatively simple public health recommendations, the enormous disproportionate toll on people of color, and the torrent of online misinformation? We urgently need data reflective of today's circumstances along with the policy to ensure it is quickly and effectively disseminated to the public health and clinical workforce.
Last year prompted in part by the measles outbreaks, Reps. Michael C. Burgess (R-TX) and Kim Shrier (D-WA), both physicians, introduced the bipartisan Vaccines Act to develop a national surveillance system to monitor vaccination rates and conduct a national campaign to increase awareness of the importance of vaccines. Unfortunately, that legislation wasn't passed. In response to COVID-19, Senate HELP Committee Ranking member Patty Murray (D-WA) has sought funds to strengthen vaccine confidence and combat misinformation with federally supported communication, research, and outreach efforts. Leading experts outside of Congress have called for this type of research, including the Sabin-Aspen Vaccine Science Policy Institute. Most recently, the National Academy of Sciences, in its report regarding the equitable distribution of the COVID-19 vaccine, included as one of its recommendations the need for "a rapid-response program to advance the science behind vaccine confidence."
Addressing trust in vaccination has never been as challenging nor as consequential. The stunning scientific achievement of COVID-19 vaccines anticipated to be ready in record time needs to be backed up by an equally ambitious and evidence-based effort to build the public's confidence in the vaccines. In its remaining days, the Trump Administration should invest in building vaccine confidence with current resources, targeting efforts to ensure COVID vaccines reduce rather than exacerbate racial and ethnic health disparities. Congress must also act to provide the additional research and outreach resources needed as well as pass the Vaccines Act so we are better prepared in the future.
If we don't succeed, COVID-19 will continue wreaking havoc on our health, our society, and our economy. We will also permanently jeopardize public trust in vaccines – one of the most successful medical interventions in human history.