Tropical Medicine focuses a group of chronic parasitic, viral and other infections that affect more than 1.4 billion people worldwide. Known as neglected tropical diseases (NTDs), these conditions are all too common among the world’s poorest people and contribute significantly to chronic ill-health and disability, particularly for children.
Texas Children’s Hospital and Baylor College of Medicine established the National School of Tropical Medicine to address the urgent need to improve healthcare strategies for the prevention, treatment and diagnosis of NTDs worldwide. Furthermore, Texas Children’s Hospital Center for Vaccine Development works with partners around the world to develop and test new vaccines against neglected and emerging infectious diseases.
Led by Dr. Peter J. Hotez, a world-renowned expert in NTDs, Texas Children’s tropical medicine program is expanding efforts to develop, manufacture and test vaccines against NTDs and other infectious diseases affecting low-income populations in the U.S. and worldwide.
The Center for Vaccine Development also supports U.S. vaccine diplomacy initiatives and public health emergency preparedness.
The National School of Tropical Medicine is the first school of its kind in the United States committed solely to addressing the world's most pressing tropical diseases. It offers a variety of basic, clinical and biotechnology educational programs to train a new generation of scientists, health professionals and public policy leaders.
Dr. Peter J. Hotez
Dean, National School of Tropical Medicine
Texas Children’s Endowed Chair of Tropical Pediatrics
Director, Texas Children’s Center for Vaccine Development
Dr. Maria Elena Bottazzi
Associate Dean, National School of Tropical Medicine
Deputy Director, Texas Children’s Center for Vaccine Development
The current approach to the control and elimination of the seven most common NTDs including the three major soil-transmitted helminth infections, schistosomiasis, lymphatic filariasis (LF), onchocerciasis, and trachoma relies on annual or twice yearly mass drug administration (MDA) in programs of so-called preventive chemotherapy. In an MDA campaign entire populations living in highly endemic areas are treated with a single dose of one or more NTDs.
Currently MDA for the major NTDs includes albendazole or mebendazole for the soil-transmitted helminth infections, praziquantel for schistosomiasis, ivermectin or diethylcarbamazine citrate for LF (together with albendazole), ivermectin for onchocerciasis, and azithromycin for trachoma. These medicines have an excellent biosafety profile and there is adequate safety data for the simultaneous administration of albendazole, ivermectin, and praziquantel. Mass drug administration has led to the elimination of LF as a public health problem in two dozen countries, as well as elimination of onchocerciasis in two countries, and trachoma in multiple countries. However, for the other major NTDs, such as for hookworm and schistosomiasis, MDA can only temporarily lower prevalence.
Today, the drugs targeting the seven most common NTDs are being combined in a "rapid impact package" using treatment algorithms shaped by the WHO, supplemented with programs for sanitation and clean water. Support from the U.S. Government (through USAID) and the UK Government (DFID) are providing health ministries in disease endemic countries medicines and technical support to implement national programs of preventive chemotherapy.
Current initiatives aimed at treating and preventing HIV/AIDS, malaria, and TB could provide an opportunity for the integration of these efforts with efforts to prevent and control NTDs. Furthermore, there is evidence that NTDs either promote susceptibility to the HIV virus or worsen the clinical course and progression of AIDS and malaria. The Center for Global Health, in collaboration with the National School of Tropical Medicine and Texas Children's Hospital Center for Vaccine Development will expand and incorporate new programs to address the prevention, care and treatment for NTDs within the already ongoing comprehensive programs nationally and worldwide. Read more.
For some of the most common NTDs, preventive chemotherapy is not considered a long-term strategy because post treatment re-infection can and usually does occur. Of particular concern are the re-infection rates for diseases such as hookworm and schistosomiasis. Moreover high rates of mebendazole failure have also been noted for hookworm. Other NTDs such as Chagas disease are not amenable to preventive chemotherapy. The long-term solution is to develop and use anthelmintic vaccines in areas of high transmission. Such "antipoverty vaccines" are under development at Texas Children's Hospital Center for Vaccine Development.
For NTDs such as Chagas and related kinetoplastid infections such as leishmaniasis and human African trypanosomiasis, case detection, management, and treatment are critical in addition to programs of integrated vector management. However, some of the medicines used for these conditions have toxic side effects and are contraindicated in pregnancy. Therefore, efforts to develop vaccines against Chagas and leishmaniasis are underway at the Center for Vaccine Development. Finally, parallel programs to develop new drugs or diagnostic tools should also be considered.
For the last decade, there has been a response from the non-profit sector to establish innovative models that would allow for the advancement of research & development that would ultimately lead to new products for the treatment, prevention and diagnosis of NTDs. These are the so-called “Product Develop Partnerships (PDPs)”, partnerships created among groups of private, public, governmental, educational, and non-profit organizations, with a goal to create innovation and advance new and inexpensive products to fight NTDs.
Among the well-established vaccine development PDPs, over the last 16 years the Center for Vaccine Development has led the development of new vaccines to combat NTDs such as hookworm infections and schistosomiasis. This work is done as part of the Human Hookworm Vaccine Initiative (HHVI) and the Schistosomiasis Vaccine Initiative (SVI), which are supported by the Bill & Melinda Gates Foundation, the Dutch Ministry of Foreign Affairs, the Brazilian Ministry of Health, the NIH, Blavatnik Charitable Foundation and Mort and Chris Hyman.
The Center for Vaccine Development uses a blueprint for the development of safe and effective vaccines against neglected tropical diseases by enhancing its capabilities to engage in antigen discovery, rapid development of scalable manufacturing processes (process development), quality control, and preclinical testing of suitable vaccine candidate antigens. In addition, it will build on the model of working with manufacturers in developing countries to transfer the technology and scale up developed processes for manufacture of pilot clinical lots under current good manufacturing practices (cGMP). The Center for Vaccine Development will continue to advance the hookworm and schistosomiasis programs and has recently initiated programs for the development of vaccines for Chagas disease and leishmaniasis, in collaboration with several key Mexican institutions and with support from the Carlos Slim Health Institute. Read more.