In the context of an unprecedented West African epidemic which started in December 2013 in Guinea and spread to Liberia and Sierra Leone, Ebola has rightfully occupied the media and public attention.
Last week the Parliamentary and Scientific Committee held a discussion meeting, ‘Ebola virus – an update’, giving parliamentarians and other attendants the opportunity to raise questions and concerns to a panel of UK experts, including the UK Chief Medical Officer (Professor Dame Sally Davies), an epidemiologist (Professor John Edmunds), a microbiologist, and representatives of Public Health England.
In today’s post I’ve summarised the information relayed by the panel.
Should we be worried about getting Ebola in Western countries?
Alongside coverage of the Ebola outbreak, media attention has sometimes lingered on the potential threat it might pose to Western countries. When asked how she deals with scare stories of outbreaks in the UK, Professor Sally Davies made clear that such speculations are not based on evidence and that her best response is to provide scientific truths and advice.
Professor Sally Davies assured attendees that Guinea, Liberia and Sierra Leone international airports have excellent screening facilities. In addition, the entrance screening procedures in the UK are highly effective. This benefits everyone, including potentially infected people who can be offered treatment earlier.
She explained that people cannot transmit the virus in the early days of the infection, and that they start being contagious only when they begin having fever. Besides, the Ebola virus is fragile – it dies within one hour on hard surfaces eg a dry table. The virus has no history of spreading through the air, and experts have advised the Chief Medical Officer that Ebola is highly unlikely to mutate into an airborne virus.
The real concern, however, is that the virus continues spreading in West Africa, making it harder and harder to control.
Epidemiologists have studied the way Ebola spreads. A key figure is the reproduction number of the virus, ie how many people a person with the disease is likely to infect. Professor John Edmunds, epidemiologist at the London School of Hygiene and Tropical Medicine, explained that the current reproduction number of Ebola in West Africa is 1.4, and that unless it falls below 1 the infection will continue to spread. Weak, unprepared regional health systems and densely populated areas, as well as local customs such as burial practices are factors that have contributed to the virus spreading in West Africa.
So far the number of Ebola cases has grown exponentially, ie it is roughly doubling every three weeks. As of late September, the US Center for Disease Control and Prevention (CDC) estimated that without further action there could be up to 1.4 million cases by mid-January.
Is there any hope to contain the disease?
Effective and fast actions will be key especially in these areas: diagnosis, isolation, and vaccines.
According to Professor Edmunds, the best way to control the current epidemic is to diagnose and isolate new cases as fast as possible. He explained that rapid diagnosis is essential as, while waiting for their results, people are kept together in isolation wards, which increases risks of cross-contamination. Thus there is a need for easy-to-use diagnostic tests that take minutes rather than hours or days, as well as more diagnosis centres in West Africa.
The panel highlighted that the UK government has led the way in providing aid, and in particular piloted diagnosis and care centres in Sierra Leone. Facilities have been set up and run with the support of the military and of many NGOs and volunteers.
High hopes are also placed on the accelerated development of treatments and vaccines. Contrary to a widespread belief, research into Ebola drugs and vaccines has been well supported in particular in the US – one of the motivations being to protect the army from tropical haemorrhagic fevers. Professor Sally Davies emphasised that three potential Ebola vaccines are particularly promising and already proven efficient in animals. Two of these vaccines are currently being tested for safety in humans (phase I clinical trials).
While it usually takes years from initial clinical trials to market release, the emergency situation prompted international institutions to fast-track experimental trials of new treatments in West Africa. The Chief Medical Officer and Public Health England said there are also ongoing worldwide discussions on methodologies, including ethical trial designs. Given the severity of the disease, experts have largely ruled out giving placebos in randomised control trials.
Perhaps, as the Washington Post reported about US state-specific ‘Right to Try’ laws, progress was inspired by past crises such as the HIV epidemic in the 1980s, recently dramatised in the Dallas Buyers Club. The film conveys the idea that US regulators should have allowed non-traditional trial designs recognising the lethal nature of the condition and the need to speed new treatments.
In the first place, vaccinating care workers in West Africa will greatly help contain the disease. Professor Sally Davies said that, ultimately, ring vaccinations around outbreaks could be used to halt future epidemics.
In brief, the West African Ebola outbreak has posed complex challenges for science and society. The discussion panel acknowledged that the initial reaction to the outbreak was too slow. But faced with the evidence, the world now seems to be gearing up to pass the real test – controlling this outbreak but also preventing future outbreaks. If local and global authorities keep the momentum and learn the lessons from this crisis, then they can make our global health systems stronger ahead of future challenges.