When we think of killer diseases of global health importance, iron-deficiency anemia (IDA) is not something that immediately comes to mind. Yet the December 2014 publication of leading causes of death by the Global Burden of Disease Study 2013 reveals that IDA kills an estimated 183,400 people annually. To put this number in perspective, in the year 2013, IDA killed more people worldwide than ovarian cancer. In terms of years of life lost, IDA ranked higher than cervical cancer.
The fact that we compared IDA to two other well-known threats to the health of women is no accident. Because women of child-bearing age have low underlying iron reserves, they are at great risk of becoming deficient in iron and progressing to IDA. Pregnant women are especially vulnerable to IDA because of the high iron demands of the growing fetus. Growing children represent another important group who develop IDA.
Human Hookworm Infection
While several factors contribute to IDA, including dietary deficiencies and iron losses through menstruation and pregnancy, human hookworm infection has been identified as one of the leading causes in impoverished countries, especially in sub-Saharan Africa, Southeast Asia, and Oceania. Hookworms are parasitic worms that attach to the inside of the intestines of children and women. Hookworms are long-lived parasites, extracting blood every day to produce sufficient blood loss that results in IDA.
Although drugs are available to treat and remove hookworms from the intestines of a young girl or woman living in poor areas of the tropics, the medicines do not always work well; even when they do work, they do not prevent hookworm reinfection within a few months to a year, allowing a terrible, dangerous, and costly cycle of infection and treatment to repeat over many years.
Developing a Vaccine
In response to this threat, the Sabin Vaccine Institute Product Development Partnership developed the first-ever human hookworm vaccine, now being advanced through a European consortium of partners—HOOKVAC—based at the Amsterdam Institute for Global Health and Development, and funded by the European Union, in addition to the Dutch Ministry of Foreign Affairs, the Bill & Melinda Gates Foundation, and the Michelson Medical Research Foundation. Through HOOKVAC, the vaccine is now in clinical testing in Gabon where more than one in four people are infected with hookworms.
HOOKVAC represents a critical enabling mechanism to advance the testing of the human hookworm vaccine. Otherwise, it is unlikely a major or multinational pharmaceutical company would initially undertake such a project, given the fact that hookworm mostly strikes only the poorest of the poor in developing countries.
HOOKVAC helps to create a path to navigate around the market failures linked to most neglected tropical disease products. The HOOKVAC Consortium has begun clinical testing in Gabon (in collaboration with the Lambarene Research Centre linked to the Albert Schweitzer Hospital) where hookworm is widespread. HOOKVAC is working to pioneer the conduct of clinical trials in resource poor settings where hookworm infection occurs.
Success in the clinical testing of the human hookworm vaccine in Gabon could lead to the development of the first vaccine that specifically targets IDA in low- and middle-income countries where hookworm infection is widespread. Indeed, another analysis linked to the Global Burden of Disease study estimates almost half a billion people are infected with hookworms, indicating that it is one of the most ubiquitous infections of the poor.
In addition to clinical trials, the HOOKVAC consortium is tasked with identifying partners in the pharmaceutical industry who can undertake the industrial-scale production of the human hookworm vaccine. Among the exciting opportunities for industrial partnering is a group of innovative developing countries, including India, Brazil, and other middle-income countries, which have a rapidly growing capacity for producing new biotechnologies, including vaccines.
While not a panacea, a vaccine to combat the hookworm could represent an important technological breakthrough in global efforts to prevent IDA. It would be a key tool alongside other measures, such as the human papillomavirus (HPV) vaccine to prevent cervical cancer, to improve the health of girls and women living in extreme poverty.