Combating Poverty Through Vaccine Development and Distribution
By Regina McEnery
In some ways, vaccine development has never looked more promising. A report released last year by the World Health Organization (WHO), the World Bank, and the United Nations Children’s Fund (UNICEF), declared that the last 10 years were the most productive ever in the history of vaccine development. Then, in January, at the World Economic Forum’s annual meeting in Davos, Switzerland, the Bill & Melinda Gates Foundation announced they were committing US$10 billion over 10 years to fund the research and development of new vaccines, and distribution of existing vaccines to people in the world’s poorest countries.
US President Barack Obama and his administration have also placed renewed emphasis on vaccine development. In a memo circulated in May, the Obama administration mentioned “seeking and then scaling up potential game-changers, such as vaccines,” as a way to solve longstanding challenges such as poverty.
While global health organizations and many public health researchers say vaccines are one of the most cost-effective ways of saving children’s lives and reducing poverty, the WHO estimates that only about 18% of the $6 billion annual global vaccine market is spent in developing countries, a point underscored at the 13th Annual Conference on Vaccine Research, which took place in Bethesda, Maryland from April 26-28.
The 400 researchers and public health workers who gathered at the meeting, which was organized by the National Foundation for Infectious Diseases, emphasized how difficult vaccine discovery and distribution can be. Vaccines typically take many years and a hefty investment of between $200 million and $500 million to develop, noted Don Francis, founder of the nonprofit organization Global Solutions for Infectious Diseases, during his keynote speech. And even when vaccines do get licensed, it can take decades until the disease is eradicated because of the logistical difficulties and expenses involved in distributing vaccines on a global scale. Although the first polio vaccine was licensed in 1955, it took 36 years for the virus to be eradicated in North America, and 50 years for it to be eradicated in all but four countries where it is still endemic, Francis noted.
Despite these obstacles, vaccine researchers are increasingly focusing on the link between poverty and disease, and the conference opened with an array of talks about the vital role human and animal vaccines can play in reducing poverty and in strengthening economic and political security, particularly in developing countries.
One area of focus is scaling up distribution of the recently licensed vaccines against rotavirus, which causes diarrheal disease, and pneumococcal bacteria, which cause pneumonia, in developing countries, where the death rate from these infections is highest. There is also more attention being given to an array of 13 so-called neglected tropical diseases (NTDs) that cause about 530,000 deaths annually and afflict about one billion of the world’s poorest people.
A number of scientists at the recent vaccine conference are hoping the emphasis on vaccines as a way to combat poverty will translate into increased funding for vaccine research and development. Though NTDs receive much less treatment and prevention funding than HIV/AIDS, tuberculosis, and malaria, they have devastating consequences on maternal and child health, and may increase susceptibility to HIV/AIDS and malaria or worsen disease progression in those already infected.
“NTDs impair intellectual and physical development in children, cause adverse pregnancy outcomes, and reduce worker productivity,” said Peter Hotez, chairman of microbiology, immunology, and tropical medicine at George Washington University Medical Center in Washington, DC.
A number of vaccine candidates against NTDs, so-called anti-poverty vaccines, are in the clinical pipeline. Hotez, who also heads up The Sabin Vaccine Institute, said they are hoping to soon begin a Phase IIb test-of-concept trial in Brazil of a vaccine candidate against hookworm, a parasitic worm that lives in the small intestine and infects about 576 million people, mostly in developing countries. Hookworm infection typically occurs when the larvae from hookworm eggs penetrate a person’s skin. The larvae eventually latch onto the intestinal wall, where they mature into adult hookworms and produce more eggs. Hookworm infection can cause, most seriously, anemia and iron deficiency due to severe blood loss. Prolonged, untreated hookworm infections can also result in mental retardation.
The Sabin Institute is also hoping to begin clinical trials of a vaccine candidate against schistosomiasis, another parasitic disease which infects approximately 207 million people worldwide, most of them in Africa. Both the Sabin Institute and the Institut Pasteur in France are developing vaccines against two different parasites that trigger schistosomiasis. The vaccines would be used along with drug treatment to reduce or delay disease progression.
Schistosomiasis is referred to as snail fever because the parasitic worms that spread the disease live in snails. People become infected when they come in contact with fresh water contaminated by the parasites that the snails excrete. The worms grow inside a person’s blood vessels and produce eggs, which then travel to the intestines or bladder. Like hookworm, repeated bouts of schistosomiasis can cause anemia and malnutrition. In rare instances, the eggs can be found in the brain or spinal cord, causing brain damage and paralysis.
More effort is also being given to control of foot-and-mouth disease, a highly contagious disease of cattle, buffalo, sheep, and pigs. The disease rarely affects humans, but the speed in which it spreads through livestock can seriously reduce milk and meat production, and the trade bans that result after outbreaks seriously affect the economies of food-exporting nations.
Researchers are excited about a novel livestock vaccine for foot-and-mouth disease developed by researcher Martin Grubman at the Plum Island Animal Research Center in New York in collaboration with the US Department of Homeland Security and GenVec, a biopharmaceutical company in Maryland. Luis Rodriguez, research leader at the Plum Island Animal Research Center, said studies of the vaccine candidate showed it was able to prevent clinical disease in cattle when they were challenged with the virus that causes foot-and-mouth disease.