It has never been possible before to do research so close to the Ebola virus

Article by Diana, doctor of the Tropical Medicine Unit of the Vall d'hebron/Drassanes, with experience in epidemics of Ebola in Angola, Uganda and Democratic Republic of Congo (with MSF). Collaborator of the Spanish Scientific Ebola Committee by training sanitary personnel. Member of the Committee of Ebola for analysis and follow-up in Catalonia:

On January 14, the World Health Organization declared that the biggest epidemic of Ebola in history had ended. A day after appeared a new a case in Sierra Leone. It seems that the virus resists to disappear, but one thing is clear, it is coming to its end ...

It's time to take stock. We leave behind 28,637 people infected and 11,316 dead. Three countries devastated by a virus that has not only brought death and suffering, but that has sunk the economy and the already precarious health system they had, collapsed trying to respond to the epidemic and leaving aside so many other priority health problems.

But it does not end here, let's not forget that there are still thousands and thousands of survivors. It is estimated that a 50% of them suffer and will suffer medical problems stemming from the disease, which is called the "post-Ebolavirus disease syndrome" (PEVDS). Thousands of people with symptoms that include chronic joint pain (87%), eye problems such as uveitis, loss of visual acuity, blurred vision (25%), headache (22%), fatigue, anorexia (98%), alteration of recent memory (27%), insomnia (19%), persistent abdominal pain (32%), sexual dysfunction (20%) *, etc. And many others, without forgetting the social consequences as the stigma and psychological conditions, such as depression or post traumatic stress, that will stay with them for long time.

The duration in time of the epidemic (over two years) as well as its huge dimensions and the high number of survivors has been a great opportunity from the scientific point of view. It has never been possible before to do research so close to the Ebola virus and its consequences. We have advanced our knowledge of the virus and in the possible experimental treatments and vaccines.

Two vaccines in phase III trials are the most advanced, the vaccine using the vesicular stomatitis virus as a vector (VsV-EBOV) and the one using the chimp adenovirus (ChAd3-ZEBOV). The two are in phase III trials and still in the phase of evaluation of results, but it is already known that they are well tolerated and that they provide a good protection against the virus. Everything seems to indicate that it might be a good option to apply in an epidemic context and especially following the ring vaccination strategy (from each infected case every contact that this generates is vaccinated, protecting the contacts directly and at the same time creating a protective circle that prevents the spread of the virus).

Regarding the treatments, some substances already used for other indications (and therefore safe) that had proven to be effective against the virus in vitro are being used in clinical trials that still last: the case of the interferons or favipiravir (Toyama, Japan). The initial findings of the latter suggest that it has some efficacy in the early stages of the infection even though there is still a lot to be researched. We also have the case of amodiaquine, anti-malaria that, according to MSF (Doctors Without Borders), has given some improvement to their Ebola patients (N Engl J Med 2016; 374:23-32). Other new substances are still in less advanced phases (phase I) as is the case of the combination of ZMapp monoclonal antibodies (Leafbio, USA) or MIL 77 (MabWorks, China), as well as other substances still in preclinical stage. With regard to the use of the serum of convalescent patients, we also have several clinical trials under way, some in stage II/III, as is the case of Sierra Leone and Guinea, where 150 patients already have been transferred. Data from these trials is currently being analysed and there are no conclusive results yet.

It has also been discovered a lot more about the virus itself. We know that the virus can remain for long in the body even after clinical recovery. It has been proved the presence of virus in semen and breast milk even months after healing. It has also been isolated in the vitreous humour of patients who have survived. It is not known yet how long these viruses can persist in certain tissues, or whether they are viable or capable of transmitting the disease to other people.

The follow up of Ebola cured men patients for months has shown in some cases the presence of virus in semen even 9 months after the healing. These viruses do not seem able to reactivate the disease in the same patient but can pose a risk of infection to others via sexual contact. The viruses are protected from the immune system by the testicular tissue. The same happens with breast milk. The recommendations in Africa are to promote the use of condoms until a year after the men patient's healing, and to recommend surviving mothers to avoid breastfeeding as long as they have other appropriate options for their babies.

The WHO, along with the CDC and the Ministry of health in Sierra Leone, work together on the project of monitoring the persistence of the virus in the survivors ("Virus Persistence Study") which includes periodic tests among both men and women to determine the durability and viability (and ability to spread by bodily fluids) of the virus in the body once the disease is overcome.

All these challenges are still on the table and the prospect of a "normal" life for these populations is still very far away. Fortunately there are actors who are still on the ground. We hope that they continue not only because of the scientific interest, but also to help the physical and moral recovery of so many thousands and thousands of people who still suffer the consequences.

The most recent studies show that the Ebola virus leaves an immunity that can last up to ten years, it is unknown if it can protect for life, and in any case it does not protect against other strains.

Epidemics of Ebola will continue popping up in Africa as they have done for many years before this latest epidemic that was all over the media. They will also continue to cause deaths. What is much less likely is that it touches the Western world as closely as this last time. Organizations such as Doctors Without Borders and others will follow in the first line, we will have to see if the international community still remembers.

Concerning us. We hope that all the efforts made to train and prepare both the healthcare structures and the professionals against the appearance of possible cases were not in vain. They should learn from the mistakes, improve the capacity to react, and know to manage the fear and the lack of knowledge in a more efficient way. Diseases are global, and new viruses and emerging diseases will appear again and again. Will we be ready?

*Qureshi AI, Chughtai M, Loua TO, et al. Study of Ebola Virus Disease Survivors in Guinea. Clin Infect Dis 2015.

Watch the pictures taken by Dr. Diana Pou