With the number of reported Ebola cases still increasing everyday, Stephen Connolly looks at what is being done to halt the growth of this deadly virus.
Since the first reported case last March, the current Ebola epidemic in West Africa has over 8,200 lives with the total number of reported cases reaching 21,000. When the University Observer last reported in September 2014 on the outbreak, the Zaire species of the RNA virus, first described in 1976, had killed 2,500 people and the total number of cases was close to 5,000. A World Health Organisation (WHO) projection made in August last year estimated that the total number infected by the virus could reach 20,000 by July 2015. This amount however has already been outstripped despite efforts by governments and international organisations to implement best practices in confining the disease. An example is Freetown in Sierra Leone where all gatherings and parties over the Christmas period were banned.
Numbers reported by the Centres for Disease Control and Prevention imply that the rate of incidence has declined in Guinea, Libera, and to a lesser extent, Sierra Leone. The disease is far from being controlled however. Sierra Leone, Liberia and Guinea remain the principally-afflicted sites of the virus, while deaths from Ebola have also occurred in Germany, Norway, the US and Spain. Small outbreaks in geographically-vulnerable countries such as Senegal and Mali have been punctually silenced as was one Nigeria. More recent and perhaps alarming to some however has been the recent diagnosis in Ebola volunteer Pauline Cafferkey in Glasgow, who remained critically ill for over a week despite experimental treatments. She was given isolated plasma from British Ebola survivor, William Pooley, and an unspecified antiviral drug, likely to be either brincidofovir or favipiravir.
Coverage of Ebola in the past month or so has disproportionately fixated on the array of tantalising experimental treatments currently evolving. The earliest of these treatments to garner such hype was the monoclonal antibody drug, ZMapp, an expensive and laboriously-produced blend of purified antibodies grown to specifically target parts of the Ebola virus shell. Despite past success in animal models and the increased survival rate in several repatriated volunteers who fell ill, little can be ascertained from the treatment’s actual benefit. Much of this survival benefit could be credited to the heightened scrutiny and care such patients inevitably received. Indeed, this is true for the evidence surrounding most the Ebola’s experimental treatments: they have been given on compassionate basis, from which virtually no information of the effectiveness can be gleaned.
In an effort to address this problem clinical trials of favipiravir and brincidofovir – both antiviral agents believed to bridle the virus’s ability to duplicate its genetic code- started in December and January in West Africa. They hope to avoid ethical issues, such as the question of randomising ill patients to placebo, by giving the drug to recruited volunteers and comparing their condition to those who do not accept the treatment but receive the same supportive care. Such study designs are not perfect but are perhaps the best that can now be offered. Results of these trials should appear by March this year.
Two vaccines are currently being developed in parallel by Britain’s GlaxoSmithKline and MSD and Newlink in Canada. They both work by inserting key genes for recognisable proteins of the Ebola virus’s surface into comparatively harmless vectors like the chimpanzee adenovirus and VSV livestock virus. This will hopefully incite an immune response that will protect the unexposed against the actual virus. Both vaccines have been designed by WHO to have ‘an acceptable safety profile’ and are being readied to undergo large-scale trials, incorporating anything from 6,000 to 9,000 people in Guinea, Liberia and Sierra Leone. On top of this, a trial of a third vaccine, manufactured by Johnson &Johnson was announced in the first week of January. This one is in fact comprised of two vaccines developed separately, now intended to be administered one to two months apart, as part of what Johnson & Johnson call a ‘prime-boost strategy’. This vaccine, while at more primitive phase-1 trials compared to the other two, is stable at temperatures between 2°C and 8°C, while the others require refrigeration below -80°C. In countries with climates and power grids as adverse as Sierra Leone and Guinea, the implications of this are easy to appreciate.
These clinical trials are being propelled at a speed previously unheard of, showing ingenuity and efficiency not witnessed since antiretrovirals were developed for HIV in the 1980s. The swiftness of this development has been assisted by organisations such as The Wellcome Trust, Médecins Sans Frontières and WHO, the latter negotiating indemnity for drug companies in light of the hazards that rushing development can create.
It is becoming increasingly plain however that it will not be a pharmaceutical innovation that ultimately encumbers the virus’s spread but rather consistent sanitation methods and shrewd management. The spectrum of mortality when comparing regions as well as the brevity of the outbreaks in wealthy countries reveals the fact that the lethality of this outbreak comes down to sheer poverty. Biopharmaceutical advances will inevitably hold the media’s focus but poor infrastructure, facilities for treating and burying the dead, availability of protective equipment and lack of cohesive strategies to identify the sick are to blame for Ebola’s continuing spread ultimately. These challenges will have to be overcome if the spread of the virus is ever going to be curbed.