By: Charles Ebikeme
Last month, the results of the largest malaria study of its kind was published in the New England Journal of Medicine, spelling out the possibility of new hope for fighting a disease that accounts for 800,000 lives lost on a yearly basis – most of them children under the age of 5. This sparked a promise of hope in controlling a disease that causes so much human death and suffering. But it is by no means the last word. As we all take a step back from the ground-breaking news of the most advanced new malaria vaccine in the field so far – the pros and cons, drawbacks and potential of the RTS,S vaccine is being debated. Those of us interested in NTDs are drawn to the next logical question: how far along are we in vaccine development for NTDs?
With NTDs a heady mix of infections caused by bacterial and parasitic agents, vaccine development for many of the NTDs will have to overcome much of the same problems of the malaria vaccine – both technically and clinically.
The benefit of a vaccine is clear for all to see, and may be complemented with drug administrations as part of a total strategy to eliminate or eradicate many of these diseases. But despite the lack of research and development that plagues the NTDs, there is some progress at hand – or, at least, there is a realization and drive for developing more ‘antipoverty’ vaccines.
Of all the NTDs on the list, only rabies is vaccine-preventable with Buruli ulcer coming in a far second (the current Bacille Calmette-Guérin (BCG) vaccine appears to offer some short-term protection). A vaccine for hookworm, the almost vampiric parasite that ingests enough blood to cause anaemia, is in development. Schistosomiasis, arguably the most important human helminth infection in terms of mortality, has one antigen vaccine in clinical trials and a number in preclinical studies. The situation is promising – many have suggested that schistosomiasis could be the next disease to be ‘consigned to history’ by the next time the MDGs have to be rewritten. We wait in hope.
Onchocerciasis, leishmaniasis, trypanosomiasis, and dengue fever are some of the other NTDs with active vaccine research and development by various non-profit entities, with a Chagas initiative in its infancy stage.
Currently there is no vaccine to protect against dengue. “We need a dengue vaccine” as proclaimed by Dr. Zulfiqar Bhutta, of the Aga Khan University Medical Center in Karachi, Pakistan, and Dr. Ciro de Quadros, of the Sabin Vaccine Insitute.
The need for a dengue vaccine is clear. With incidences of the disease increasing over 30 fold in the last half century, mosquito vector control is proving to be not enough. More tools are needed. Even though dengue vaccines have been in development in one form or another since the 1940s, it has been in a languished state. Today, several vaccines are in various stages of advanced development, with clinical trials currently underway on five candidate vaccines, with the hopes of licensing a leading candidate vaccine as early as 2015.
Many of the most at risk are usually the last to get vaccines. Even though we are not quite there yet on some of the NTD vaccines, feasible options exist to ensure access to the potential vaccines by the poorest communities. The expertise and funds exists to provide access, as well as the possibility of piggy-backing on other health services, not to mention the programs of the “big three disease” of HIV/AIDS, tuberculosis and malaria. This time it seems, for once, only our science and not our will is lacking.
Charles Ebikeme has worked for many years as a research scientist on African Sleeping Sickness. Possessing a MSc from the London School of Hygiene & Tropical Medicine, and a PhD in Parasitology from the University of Glasgow, Charles currently blogs and writes for the All Results Journals – a new publication system focusing on negative results – covering topics on the hidden side of the scientific publication process.