I dislike the term “neglected tropical diseases.” This collection of communicable diseases is neglected — a pejorative term — only by countries unaffected by them. They aren’t neglected by the 1 billion or more individuals afflicted with them, the millions who die from them, or the countries in which they live.
The World Health Organization initially listed 13 diseases as “neglected.” Gaining consensus around what constitutes these diseases is as difficult as pronouncing dracunculiasis, schistosomiasis, or chromoblastomycosis. What’s more, there are diseases that kill tens or hundreds of thousands of people every year that don’t make the list, like hepatitis E, which kills 70,000 pregnant women a year, and group A streptococcus (the cause of strep throat), which kills 500,000 people a year.
Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine, has argued that many of the neglected diseases aren’t exclusively “tropical” or even relegated to developing countries: dengue and Chagas disease have certainly been problems in the United States.
An alternative designation, poverty-associated infectious diseases (PAID), better captures the essence of this hodgepodge. But it doesn’t do much to help define, prioritize, fund, and create incentives for action to reduce the burden of PAID around the world.
What should be done to remedy this systematic failure, including the failure to promptly develop vaccines, the most cost-effective approach to infectious diseases and an essential part of the comprehensive solution to these diseases?
Given the wide variety of these diseases, their symptoms, and the populations they affect, there is no face, no poster child that can be used to excite the sympathy of donors, engage the imagination of funders, or raise the specter of global contagion.
At the most basic level, the global health community isn’t certain of the magnitude of some of these diseases. Does hepatitis E kill 70,000 people a year (the most widely quoted estimate) or 10,000 a year (the estimate provided by the Bill and Melinda Gates Foundation-funded Institute for Health Metrics Evaluation)? Does schistosomiasis kill 12,000 people a year or 200,000?
There isn’t consensus on how to prioritize work against poverty-associated infectious diseases. Should we pick low-hanging fruit such as guinea worm, which now afflicts a small number of people (30 cases worldwide) but is nearing eradication, or should we focus on non-typhoidal salmonella that may kill 680,000 this year?
If these diseases affected developed countries, incentives would exist for companies to develop new diagnostics, drugs, and vaccines. There would be funding to understand the critical elements of disease transmission and to implement effective prevention and control programs.
It seems remarkable that the G-FINDER public search tool, a source of information on research funding, indicates that $1 billion is spent each year on neglected tropical disease research. Yet 80 percent of that funding goes to HIV/AIDS, tuberculosis, and malaria, short-changing the other poverty-associated infectious diseases. Group A streptococcal disease, for example, received around $1 million in 2016 despite causing 500,000 deaths each year.
Incentives are the complement to government research funding. If the U.S. National Institutes of Health funding pushes innovation, the promise of a “big vaccine” — and with it the creation of shareholder value — serves as a lure. If major vaccine companies were given sufficient incentives, including the removal of risk-related disincentives, to develop vaccines for Mali or South Sudan, perhaps solutions would already be at hand for schistosomiasis.
Remarkable vaccines now exist against diseases like rotavirus diarrhea and cervical cancer that are problems in high-income as well as low-income countries. Getting those new products into vaccination programs has been a real achievement. But can we now flip the model and develop new vaccines against diseases that are a bigger problem in developing countries that might also be useful in high-income countries as well?
From a pharmaceutical company’s perspective, it may cost $500 million to $1 billion to develop a vaccine, and only 1 in 10 new vaccines eventually reach the commercial market. In short, vaccines are expensive to develop and have a high risk of failure. That investment of time and money may pay off for a vaccine against pneumonia — Pfizer’s Prevenar brought in nearly $6 billion in 2017 — but it doesn’t for vaccines against dysentery, strep throat, or schistosomiasis that afflict people whose average income is less than a dollar a day.
In the United States, the Food and Drug Administration has a tropical disease program that grants a priority review voucher for a future (unspecified) product if a company licenses a vaccine against a particular poverty-associated infectious disease. These vouchers can be traded, and can have a value in the hundreds of millions of dollars. This is a start, but it hasn’t solved the problem.
Even for vaccines whose development has been substantially funded by philanthropy, such as GlaxoSmithKline’s malaria vaccine, the in-kind, opportunity, and delay-associated costs are risks borne by pharma with only a halo effect as an incentive. I am not defending multinational pharmaceutical companies, but we must recognize that they have a number of global health vaccines in early development they have decided not to proceed further with. Instead, they wait in company freezers.
Is this simply a lack of leadership? The horrors of Ebola led to a realization that the timely development of vaccines for particular epidemic diseases was impossible without a coordinated, international effort. Out of this was born the Coalition for Epidemic Preparedness Innovations, which launched in 2017 at the World Economic Forum with support from countries such as Norway, Germany, Britain, Japan, and India, and from philanthropic foundations such as the Gates Foundation and the Wellcome Trust. The coalition’s fund initially targeted vaccines for three diseases with outbreak potential — Middle East respiratory syndrome, Lassa fever, and Nipah — and it now has pledges of more than $740 million.
Neglected diseases should not be victims. They must find a voice to attract leadership, advocacy, and funding so we can put PAID to solving these pressing global health needs. One useful strategy would be to prioritize and incentivize the development of vaccines for diseases that are a bigger problem in developing countries but that could also be useful in high-income countries.
Health policy experts, politicians, CEOs, philanthropists, and others must step up and be the voice of the neglected. We know the problem and we have the solution in our hearts, our minds, and our wallets.
Jerome Kim, M.D., is the director general of the International Vaccine Institute, a South Korea-based nonprofit international organization devoted to the discovery, development, and delivery of vaccines for global health.
