While the pace of the Ebola epidemic that has raged across Liberia, Guinea and Sierra Leone since March 2014 appears to be slowing, researchers are rushing to roll out Phase III trials for vaccines against the disease.
However with the official death toll across the region at nearly 9,000, and the three worst-affected economies looking at GDP losses in the billions, critics claim the investment in research and prevention may have come too late - at least, for this outbreak.
The first batch of one vaccine, developed by UK-based drug major GlaxoSmithKline (GSK) and the US National Institute of Allergy and Infectious Disease (NIAID), arrived in Liberia on 23 January. The second vaccine, developed by the the government of Canada and licensed to NewLinks Genetics Corporation, has shown promising signs of resistance to the virus in Phase I trials, though that research has yet to be published.
The model used to roll out the vaccine trials at this accelerated rate is unusual. Under normal circumstances, vaccine development takes years. However, the severity of this Ebola outbreak has prompted a coalition of researchers, pharmaceutical companies, governments and regulatory bodies such as the World Health Organization (WHO) to take unprecedented steps to fast track development.
“The Ebola outbreak is an unusual and fast moving situation and demands an accelerated response,” Catherine Hartley, a spokesperson for GSK, tells This Is Africa.
“We have only been able to achieve this thanks to incredible cooperation between various different partners. There will be lessons we can take from this for the future, in particular how we better prepare ourselves to respond to future outbreaks of disease.”
Trial candidates will be divided at random into three groups, and administered either one of the two candidate vaccines or a placebo. Recipients will not know which group they are assigned to. The trial will recruit from among the general population, as well as at-risk groups such as frontline health care workers.
A slow start?
While the accelerated trials demonstrate the commitment of drug developers and researchers to finding a means to prevent another outbreak, stakeholders have been subject to criticism for a slow response to the early signs of the outbreak, and for failure to develop vaccines and treatments preemptively.
“There was a slow response locally, out of ignorance and under-estimation, and the international community also was slow – except for Médecins Sans Frontières. But you cannot expect an NGO to be in charge of a whole country,” Professor Peter Piot, director of the London School of Hygiene and Tropical Medicine and the microbiologist who first discovered the Ebola virus in 1976, said in December.
Part of the problem is that diseases such as Ebola tend to be under-researched and under-funded by drug companies and regulatory bodies alike. Ebola only has sporadic outbreaks and, despite its severity, the disease does not have the widespread prevalence of others like malaria or tuberculosis. For drug companies, this might make it a less lucrative area to invest in. For the public sector, this makes it less of a priority.
“Perhaps for this reason, compared to the focus given to the WHO’s 17 neglected tropical diseases, malaria, HIV and TB which also affect poor countries, Ebola has so far not been prioritised by the international community as an area for research and vaccine development,” GSK’s Ms Hartley argues.
Another challenge is the highly lethal nature of Ebola, making research on the disease difficult and dangerous. According to the WHO, mortality from the disease after infection averages 50 percent, although that has ranged from 25 to 90 percent in past outbreaks.
Despite these hurdles, the NIH-run trial in Liberia is not the only vaccine research underway. Another trial is due to begin in Guinea at the end of February 2015 through a collaboration between the WHO, Doctors Without Borders, the Norwegian Institute of Public Health, and other partners.
According to Dr John-Arne Røttingen, professor of global health at Harvard and one of the lead researchers on the Guinea trial, researchers will identify new Ebola cases and offer vaccination for those in close contact. This method aims to minimise the disease’s spread while maximising researchers’ ability to identify the vaccines’ efficacy in preventing transmission. This technique, called “ring vaccination”, was previously used to eradicate smallpox.
“This would hopefully require a smaller number of people needing to be vaccinated to evaluate the study, and a shorter time required to complete evaluation of whether the vaccine is protecting against Ebola viral disease or not,” Dr Røttingen explains.
However, as infection rates across west Africa have fallen, what has spelled good news from a public health perspective may make research efforts even more difficult. Vaccine trials require that healthy candidates be exposed to the disease in question - otherwise researchers will not be able to tell whether the vaccine is working. Sourcing enough candidates for both trials may prove challenging.
Another recurring obstacle health workers and researchers combatting Ebola have encountered is the distrust and resistance of at-risk populations to medical advice, founded on long-standing skepticism of public services and institutions in underserved communities. Dr Røttingen anticipates the vaccine trials will need to work to counteract these beliefs.
“A strong engagement of the communities in the study area will be required to overcome the understandable skepticism towards clinical testing of new forms of treatment,” he says.
Researchers on both trials credit the unprecedented level of cooperation across sectors and geographies in bringing the vaccines to trial so quickly. Hopefully these coalitions will be able to carry the momentum generated by these advances so that the response to the next outbreak can preempt another crisis on this scale.
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