Western African Ebola virus epidemic

Epidemiology

Outbreak

The 2013–2016 outbreak, caused by the Ebola virus (EBOV), was the first anywhere in the world to reach epidemic proportions. Extreme poverty, dysfunctional healthcare systems, distrust of government after years of armed conflict, and the delay in responding for several months, all contributed to the failure to control the epidemic. Other factors, per media reports, included local burial customs of washing the body and the unprecedented spread of Ebola to densely populated cities.

It is generally believed that a one or two-year-old boy, later identified as Emile Ouamouno, who died in December 2013 in the village of Méliandou in Guinea, was the index case. His mother, sister, and grandmother later became ill with similar symptoms and also died; people infected by these initial cases spread the disease to other villages. These early cases were diagnosed as other conditions more common to the area and the disease had several months to spread before it became recognised as Ebola.

On 25 March 2014, the WHO indicated that Guinea's Ministry of Health had reported an outbreak of Ebola virus disease in four southeastern districts and that suspected cases in the neighbouring countries of Liberia and Sierra Leone were being investigated. In Guinea, a total of 86 suspected cases, including 59 deaths, had been reported as of 24 March. By late May, the outbreak had spread to Conakry, Guinea's capital—a city of about two million people. On 28 May, the total number of reported cases had reached 281, with 186 deaths.

In Liberia, the disease was reported in four counties by mid-April 2014 and cases in Liberia's capital Monrovia were reported in mid-June. The outbreak then spread to Sierra Leone and progressed rapidly. By 17 July, the total number of suspected cases in the country stood at 442, surpassing those in Guinea and Liberia. By 20 July, additional cases of the disease had been reported by the media in the Bo District, while the first case in Freetown, Sierra Leone's capital, was reported in late July.

As the epidemic progressed, a small outbreak occurred in Nigeria that resulted in 20 cases and another in Mali with seven cases. Four other countries (Senegal, Spain, the United Kingdom and the United States) also reported cases imported from Western Africa, which were quickly isolated and led to no other infections, with the exception of the US.

Countries that experienced widespread transmission

On 25 March 2014, the WHO reported an outbreak of Ebola virus disease in four southeastern districts of Guinea with a total of 86 suspected cases, including 59 deaths. MSF assisted the Ministry of Health by establishing Ebola treatment centres in the epicentre of the outbreak. On 31 March, the U.S. Centers for Disease Control and Prevention (CDC) sent a team to assist in the response. Thinking that the spread of the virus had been contained, MSF closed its treatment centres in May, leaving only a skeleton staff to handle the Macenta region. However, in late August, according to media reports, large numbers of new cases reappeared in the region.

In February 2015, Guinea recorded a rise in cases; health authorities stated that this was related to the fact that they "were only now gaining access to faraway villages", where violence had previously prevented them from entering. On 14 February, violence erupted and an Ebola treatment centre near the centre of the country was destroyed. Guinean Red Cross teams said they had suffered an average of 10 attacks a month over the previous year; MSF reported that acceptance of Ebola education remained low and that further violence against their workers might force them to leave.

Resistance to interventions by health officials among the Guinean population remained greater than in Sierra Leone and Liberia, per media reports, raising concerns over its impact on ongoing efforts to halt the epidemic; in mid-March, there were 95 new cases, and on 28 March, and a 45-day "health emergency" was declared in five regions of the country. On 25 May, six persons were placed in prison isolation after they were found travelling with the corpse of an individual who had died of the disease. On 1 June, it was reported that violent protests in a north Guinean town at the border with Guinea-Bissau had caused the Red Cross to withdraw its workers.

In late June 2015, the WHO reported that "weekly case incidence has stalled at between 20 and 27 cases since the end of May, whilst cases continue to arise from unknown sources of infection, and to be detected only after post-mortem testing of community deaths". On 29 July, a sharp decline in cases was reported; the number of cases eventually plateaued at one or two cases per week in early August.

On 28 October, an additional three cases were reported in the Forécariah Prefecture by the WHO. On 6 November, a media report indicated Tana village to be the last known place with Ebola in the country, and on 11 November, WHO indicated that no Ebola cases were reported in Guinea; this was the first time since the epidemic began that no cases had been reported in any country. On 17 November, the last Ebola patient in Guinea had recovered, and was discharged from the hospital on 28 November. On 29 December 2015, the WHO declared Guinea Ebola-free.

Western African countries with limited local cases

In March 2014, Senegal closed its southern border with Guinea, but on 29 August, the health minister announced the country's first case, who was being treated in a Dakar hospital. The patient was a native of Guinea who had travelled to Dakar, arriving on 20 August. On 28 August 2014, authorities in Guinea issued an alert that a person who had been in close contact with an Ebola-infected patient had escaped their surveillance system. The alert prompted testing for Ebola at the Dakar laboratory, and the positive result launched an investigation, triggering urgent contact tracing. On 10 September, it was reported that the initial case had recovered. No further cases were reported, and on 17 October 2014, the WHO officially declared that the outbreak in Senegal had ended.

The first case in Nigeria was a Liberian-American, who flew from Liberia to Nigeria's most populated city of Lagos on 20 July 2014. On 6 August 2014, the Nigerian health minister told reporters that one of the nurses who attended to the Liberian had died from the disease. Five newly confirmed cases were being treated at an isolation ward.

On 22 September 2014, the Nigerian health ministry announced, "As of today, there is no case of Ebola in Nigeria." According to the WHO, 20 cases and 8 deaths were confirmed, including the imported case, who also died. Four of the dead were health workers who had cared for the index case.

The WHO's representative in Nigeria officially declared the country Ebola-free on 20 October 2014, stating it was a "spectacular success story". Nigeria was the first African country to be declared Ebola-free. This was largely due to the early quarantine efforts of Dr. Ameyo Stella Adadevoh.

On 23 October 2014, the first case of Ebola virus disease in Mali was confirmed in the city of Kayes—a two-year-old girl who had arrived from Guinea and died the next day. Her father had worked for the Red Cross in Guinea and also in a private health clinic; he had died earlier in the month, likely from an Ebola infection contracted in the private clinic. It was later established that several family members had also died of Ebola. The family had returned to Mali after the father's funeral. All contacts were followed for 21 days, with no further spread of the disease reported.

Other countries with limited local cases

On 29 December 2014, Pauline Cafferkey, a British aid worker who had just returned to Glasgow from Sierra Leone, was diagnosed with Ebola. She was treated and released from hospital on 24 January 2015. On 8 October, she was readmitted for complications caused by the virus. On 14 October, her condition was listed as "critical" and 58 individuals were being monitored and 25 received an experimental vaccination, being close contacts.

On 21 October, she was diagnosed with meningitis caused by the virus persisting in her brain. On 12 November, she was released from hospital after making a full recovery. On 23 February, Cafferkey was admitted for a third time, "under routine monitoring by the Infectious Diseases Unit ... for further investigations".

On 12 May 2015, it was reported that a nurse, who had been working in Sierra Leone, had been diagnosed with Ebola after returning home to the Italian island of Sardinia. He was treated at Spallanzani Hospital, the national reference centre for Ebola patients. On 10 June, it was reported that he had recovered and was released from the hospital.

On 5 August 2014, the Brothers Hospitallers of Saint John of God confirmed that Brother Miguel Pajares, who had been volunteering in Liberia, had become infected. He was evacuated to Spain and died on 12 August. On 21 September it was announced that Brother Manuel García Viejo, another Spanish citizen who was medical director at the St John of God Hospital Sierra Leone in Lunsar, had been evacuated to Spain from Sierra Leone after being infected with the virus. His death was announced on 25 September.

In October 2014, a nursing assistant, Teresa Romero, who had cared for these patients became unwell and on 6 October tested positive for Ebola, making this the first confirmed case of Ebola transmission outside of Africa. On 19 October, it was reported that Romero had recovered, and on 2 December the WHO declared Spain Ebola-free.

On 30 September 2014, the CDC declared its first case of Ebola virus disease. Thomas Eric Duncan became infected in Liberia and travelled to Dallas, Texas, on 20 September. On 26 September, he fell ill and sought medical treatment, but was sent home with antibiotics. He returned to the hospital by ambulance on 28 September and was placed in isolation and tested for Ebola. He died on 8 October. Two cases stemmed from Duncan, when two nurses that had treated him tested positive for the virus; they were declared Ebola-free on 24 and 22 October, respectively.

Countries with medically evacuated cases

Many people who had become infected with Ebola were medically evacuated for treatment in isolation wards in Europe or the US. They were mostly health workers with one of the NGOs in Western Africa. Except for a single isolated case in Spain, no secondary infections occurred as a result of the medical evacuations. The US accepted four evacuees and three were flown to Germany.

France, Italy, the Netherlands, Norway, Switzerland, and the United Kingdom received two patients (and five who were exposed).

Unrelated outbreak in the Democratic Republic of the Congo

In August 2014, the WHO reported an outbreak of the Ebola virus in the Boende District, part of the northern Équateur province of the Democratic Republic of the Congo (DRC), where 13 people were reported to have died of Ebola-like symptoms. Genetic sequencing revealed that this outbreak was caused by the Zaire Ebola species, which is native to the DRC; there have been seven previous Ebola outbreaks in the country since 1976. The virology results and epidemiological findings indicated no connection to the epidemic in Western Africa. The WHO declared the outbreak over on 21 November 2014, after a total of 66 cases and 49 deaths.

Virology

Of the four disease-causing viruses in the genus Ebolavirus, Ebola virus (or the Zaire Ebola virus) was the virus responsible for the epidemic in Western Africa.

Since the discovery of the Ebola viruses in 1976, Ebola virus disease has been confined to areas in Middle Africa, where it is native. The epidemic was initially thought to be caused by a new species native to Guinea, rather than being imported from Middle to Western Africa. Further studies have shown that the outbreak was likely caused by an Ebola virus lineage that spread from Middle Africa via an animal host within the last decade, with the first viral transfer to humans in Guinea. and with 341 genetic changes in the virion.

In a report released in August 2014, researchers tracked the spread of Ebola in Sierra Leone from the group first infected—13 women who had attended the funeral of the traditional healer, where they contracted the disease. This provided "the first time that the real evolution of the Ebola virus [could] be observed in humans." The research showed that the outbreak in Sierra Leone was sparked by at least two distinct lineages introduced from Guinea at about the same time. It is not clear whether the traditional healer was infected with both variants or if perhaps one of the women attending the funeral was independently infected. As the Sierra Leone epidemic progressed, one virus lineage disappeared from patient samples, while a third one appeared.

In January 2015, the media stated researchers in Guinea had reported mutations in the virus samples that they were looking at. According to them, "We've now seen several cases that don't have any symptoms at all, asymptomatic cases. These people may be the people who can spread the virus better, but we still don't know that yet. A virus can change itself to [become] less deadly, but more contagious and that's something we are afraid of." A 2015 study suggested that accelerating the rate of mutation of the Ebola virus could make the virus less capable of infecting humans. In this animal study, the virus became practically non-viable, consequently increasing survival.

Transmission

Animal to human transmission

The initial infection is believed to occur after an Ebola virus is transmitted to a human by contact with an infected animal's body fluids. Evidence strongly implicates bats as the reservoir hosts.

Bats drop partially eaten fruit and pulp, and then land mammals feed on this fallen fruit. This chain of events forms a possible indirect means of transmission from the natural host to animal populations. As primates in the area were not found to be infected and fruit bats do not live near the location of the initial zoonotic transmission event in Meliandou, Guinea, it is suspected that the index case occurred after a child had contact with an insectivorous bat from a colony near the village.

The continent of Africa has experienced deforestation in several areas or regions; this may contribute to recent outbreaks, including this epidemic, as initial cases have been in the proximity of deforested lands where fruit-eating bats' natural habitat may be affected, though 100% of evidence does not as yet exist.

Human-to-human transmission

Before this outbreak, it was believed that human-to-human transmission occurred only via direct contact with blood or bodily fluids from an infected person who is showing symptoms of infection, by contact with the body of a person who had died of Ebola, or by contact with objects recently contaminated with the body fluids of an actively ill infected person.

It is now known that the Ebola virus can be transmitted sexually. Studies have suggested that the virus can persist in seminal fluid, with a study released in September 2016 suggesting that the virus may survive more than 530 days after infection. EBOV RNA in semen is not the same as perseverance of EBOV in semen, however the "clinical significance of low levels of virus RNA in convalescent" healthy individuals is unknown.

In September 2014, the WHO reported: "No formal evidence exists of sexual transmission, but sexual transmission from convalescent patients cannot be ruled out. There is evidence that the live Ebola virus can be isolated in seminal fluids of convalescent men for 82 days after the onset of symptoms. Evidence is not available yet beyond 82 days." In April 2015, following a report that the RNA virus had been detected in a semen sample six months after a man's recovery, the WHO issued a statement: "Ebola survivors should consider correct and consistent use of condoms for all sexual acts beyond three months until more information is available."

The WHO based their new recommendations on a March 2015 case, in which a Liberian woman who had no contact with the disease other than having had unprotected sex with a man who had had the disease in October 2014, was diagnosed with Ebola. On 14 September 2015, the body of a girl who had died in Sierra Leone tested positive for Ebola and it was suspected that she may have contracted the disease from the semen of an Ebola survivor who was discharged in March 2015. According to some news reports, a new study to be published in the New England Journal of Medicine indicated that the RNA virus could remain in the semen of survivors for up to six months, and according to other researchers, the RNA virus could continue in semen for 82 days and maybe longer. Furthermore, Ebola RNA had been found up to 284 days post-onset of viral symptoms.

Containment and control

In August 2014, the WHO published a road map of the steps required to bring the epidemic under control and to prevent further transmission of the disease within Western Africa; the coordinated international response worked towards realising this plan.

Surveillance and contact tracing

Contact tracing is an essential method of preventing the spread of the disease. This requires effective community surveillance so that a possible case of Ebola can be registered and accurately diagnosed as soon as possible, and subsequently finding everyone who has had close contact with the case and tracking them for 21 days. However, this requires careful record-keeping by properly trained and equipped staff.

On 3 September 2014, WHO Assistant Director-General for Global Health Security Keiji Fukuda said, "We don't have enough health workers, doctors, nurses, drivers, and contact tracers to handle the increasing number of cases." There was a massive effort to train volunteers and health workers, sponsored by United States Agency for International Development (USAID). According to WHO reports, 25,926 contacts from Guinea, 35,183 from Liberia and 104,454 from Sierra Leone were listed and traced as of 23 November 2014.

Ebola control is hindered by the fact that current diagnostic tests require specialised equipment and highly trained personnel. Since there are few suitable testing centres in Western Africa, this delays diagnosis. As of February 2015 many rapid diagnostic tests were under trial. In September 2015, a new chip-based testing method that can detect Ebola accurately was reported. This new device allows for the use of portable instruments that can provide immediate diagnosis.

Difficulties in attempting to halt transmission have also included the multiple disease outbreaks across country borders. Dr Peter Piot, the scientist who co-discovered the Ebola virus, stated that the outbreak was not following its usual linear patterns as mapped out in earlier outbreaks—this time the virus was "hopping" all over the Western African epidemic region. Furthermore, most past epidemics had occurred in remote regions, but this outbreak spread to large urban areas, which had increased the number of contacts an infected person might have and made transmission harder to track and break. On 9 December, a study indicated that a single individual introduced the virus into Liberia, causing the most cases of the disease in that country.

Community awareness

To reduce the spread, the WHO recommended raising community awareness of the risk factors for Ebola infection and the protective measures individuals can take. These include avoiding contact with infected people and regular hand washing using soap and water. A condition of extreme poverty exists in many of the areas that experienced a high incidence of infections. According to the director of the NGO Plan International in Guinea, "The poor living conditions and lack of water and sanitation in most districts of Conakry pose a serious risk that the epidemic escalates into a crisis. People do not think to wash their hands when they do not have enough water to drink." One study showed that once people had heard of the Ebola virus disease, hand washing with soap and water improved, though socio-demographic factors influenced hygiene. Several organisations enrolled local people to conduct public awareness campaigns among the communities in Western Africa.

Denial in some affected countries also made containment efforts difficult. Language barriers and the appearance of medical teams in protective suits sometimes increased fears of the virus. In Liberia, a mob attacked an Ebola isolation centre, stealing equipment and "freeing" patients while shouting "There's no Ebola." Red Cross staff were forced to suspend operations in southeast Guinea after they were threatened by a group of men armed with knives. In September, in the town of Womey in Guinea, suspicious inhabitants wielding machetes murdered at least eight aid workers.

An August 2014 study found that nearly two-thirds of Ebola cases in Guinea were believed to be due to burial practices including washing of the body of one who had died.

In November, WHO released a protocol for the safe and dignified burial of people who die from Ebola virus disease. Speaking on 27 January 2015, Guinea's Grand Imam, the country's highest cleric, gave a very strong message saying, "There is nothing in the Koran that says you must wash, kiss or hold your dead loved ones," and he called on citizens to do more to stop the virus by practising safer burying rituals that do not compromise tradition.

During the height of the epidemic, most schools in the three most affected countries were shut down and remained closed for several months. During the period of closure UNICEF and its partners established strict hygiene protocols to be used when the schools were reopened in January 2015. Their efforts included installing hand-washing stations and distributing millions of bars of soap and chlorine and plans for taking the temperature of children and staff at the school gate. Their efforts were complicated by the fact that less than 50% of the schools in these three countries had access to running water.

Travel restrictions and quarantines

There was serious concern that the disease would spread further within Western Africa or elsewhere in the world. On 8 August 2014, a cordon sanitaire, a disease-fighting practice that forcibly isolates affected regions, was established in the triangular area where Guinea, Liberia, and Sierra Leone are separated only by porous borders and where 70 percent of the known cases had been found. This was subsequently replaced by a series of checkpoints for hand-washing and measuring body temperature on major roads throughout the region, staffed either by local volunteers or by the military.

Many countries considered imposing travel restrictions to or from the region. On 2 September 2014, WHO Director-General Margaret Chan advised against this, saying that they were not justified and that they would prevent medical experts from entering the affected areas. UN officials working on the ground also criticised the travel restrictions, saying the solution was "not in travel restrictions but in ensuring that effective preventive and curative health measures are put in place".

MSF also spoke out against the closure of international borders, calling them "another layer of collective irresponsibility". In December 2015, the CDC indicated that it would no longer make the recommendation for US citizens going to Sierra Leone to be extra careful. However, the CDC further indicated that individuals travelling to the country should take precautions with sick people and body fluids, and avoid contact with animals.

There was concern that people returning from affected countries, such as health workers and reporters, may have been incubating the disease and become infectious after arriving. Guidelines for returning workers were issued by a number of agencies, including the CDC, MSF, Public Health England, and Public Health Ontario.

Protective clothing

One of the primary reasons for the spread of the disease is the low-quality health systems in the parts of Africa where the disease occurs. The risk of transmission is increased among those caring for people infected. Recommended measures when caring for those who are infected include medical isolation via the proper use of boots, gowns, gloves, masks, goggles, and sterilizing all equipment and surfaces. One of the biggest dangers of infection faced by medical staff requires their learning how to properly suit up and remove personal protective equipment. Full training for wearing protective body clothing can take 10 to 14 days.

The Ebola epidemic caused an increasing demand for protective clothing. A full set of protective clothing includes a suit, goggles, a mask, socks and boots, and an apron. Boots and aprons can be disinfected and reused, but everything else must be destroyed after use. Health workers change garments frequently, discarding gear that has barely been used. This not only takes a great deal of time but also exposes them to the virus because, for those wearing protective clothing, one of the most dangerous moments for contracting Ebola is while suits are being removed.

The protective clothing sets that MSF uses cost about $75 apiece. Staff who have returned from deployments to Western Africa say the clothing is so heavy that it can be worn for only about 40 minutes at a stretch. A physician working in Sierra Leone has said: "At that point, you have to exit for your safety ... Here it takes 20–25 minutes to take off a protective suit and must be done with two trained supervisors who watch every step militarily to ensure no mistakes are made because a slip-up can easily occur and of course can be fatal." By October, there were reports that protective outfits were beginning to be in short supply and manufacturers began to increase their production.

USAID published an open competitive bidding for proposals that address the challenge of developing "new practical and cost-effective solutions to improve infection treatment and control that can be rapidly deployed; 1) to help health care workers provide better care and 2) transform our ability to combat Ebola". On 12 December 2014, USAID announced the result of the first selection in a press release.

On 17 December 2014, a team at Johns Hopkins University developed a prototype breakaway hazmat suit, and was awarded a grant from the USAID to develop it. The prototype has a small, battery-powered cooling pack on the worker's belt.

Treatment and management

No proven Ebola virus-specific treatment presently exists; however, measures can be taken to improve a patient's chances of survival. Symptoms usually begin with a sudden influenza-like illness characterised by feeling tired, and pain in the muscles and joints. Later symptoms often include severe vomiting and diarrhoea. In past outbreaks, it has been noted that some patients bleed internally and/or externally; however data published in October 2014 showed that this had been a rare symptom in the Western African outbreak.

Without fluid replacement, such an extreme loss of fluids leads to dehydration, which in turn may lead to hypovolaemic shock—a condition in which there is not enough blood for the heart to pump through the body. If a patient is alert and is not vomiting, oral rehydration therapy may be instituted, but patients who are vomiting or are delirious must be hydrated with intravenous (IV) therapy.

Administration of IV fluids is difficult in the African environment. Inserting an IV needle while wearing three pairs of gloves and goggles that may be fogged is difficult, and once in place, the IV site and line must be constantly monitored. Without sufficient staff to care for patients, needles may become dislodged or pulled out by a delirious patient. A patient's electrolytes must be closely monitored to determine correct fluid administration, for which many areas did not have access to the required laboratory services.

Treatment centres were overflowing with patients while others waited to be admitted; dead patients were so numerous that it was difficult to arrange for safe burials. MSF took a conservative approach. While using IV treatment for as many patients as they could manage, they argued that improperly managed IV treatment was not helpful and may even kill a patient. They also said that they were concerned about further risk to already overworked staff. In 2015 experts studied the mortality rates of different treatment settings, and given the wide differences in variables that affected outcomes, adequate information had not yet been gathered to make a definitive statement about what constituted optimal care in the Western African setting.

Paul Farmer of Partners in Health, an NGO that began to treat Ebola patients in January 2015, strongly supported IV therapy for all Ebola patients stating: "What if the fatality rate isn't the virulence of disease but the mediocrity of the medical delivery?" Farmer suggested that every treatment facility should have a team that specializes in inserting IVs, or better yet, peripherally inserted central catheter lines. In 2020, viewing the information gathered from the pandemic Farmer noted that there were almost no deaths in the U.S. and European patients because they had received optimal care.

Post-Ebola virus syndrome

There are at least 17,000 people who have survived infection from the Ebola virus in Western Africa; some of them have reported lingering health effects. In early November, a WHO consultant reported: "Many of the survivors are discharged with the so-called Post-Ebola Syndrome. We want to ascertain whether these medical conditions are due to the disease itself, the treatment given or chlorine used during disinfection of the patients. This is a new area for research; little is known about the post-Ebola symptoms." In August 2015, the WHO held a meeting to work out a "Comprehensive care plan for Ebola survivors" and identify research needed to optimise clinical care and social well-being. Stating that "the Ebola outbreak has decimated families, health systems, economies, and social structures", the WHO called the aftermath of the epidemic "an emergency within an emergency."

On 22 January, the WHO issued Clinical Care for Survivors of Ebola Virus Disease: Interim Guidance. The guidance covers specific issues like musculoskeletal pain, which is reported in up to 75% of survivors. The pain is symmetrical and more pronounced in the morning, with the larger joints most affected. There is also possible periarticular tenosynovitis affecting the shoulders. The WHO guidelines advise to distinguish non-inflammatory arthralgia from inflammatory arthritis. Concerning ocular problems, sensitivity to light and blurry vision have been indicated among survivors. Among the aftereffects of Ebola virus disease, uveitis and optic nerve disease could appear after an individual is discharged. Ocular problems could threaten sight in survivors, thus the need for prompt treatment. In treating such individuals, the WHO recommends urgent intervention if uveitis is suspected. Hearing loss has been reported in Ebola survivors 25% of the time.

In February 2015, a Sierra Leone physician said about half of the recovered patients she saw reported declining health and that she had seen survivors go blind. In May 2015, a senior consultant to the WHO said that the reports of eye problems were especially worrying because "there are hardly any ophthalmologists in Western Africa, and only they have the skills and equipment to diagnose conditions like uveitis that affect the inner chambers of the eye."

Level of care

As the outbreak progressed, the media reports, many hospitals, short on both staff and supplies, were overwhelmed and closed down, leading some health experts to state that the inability to treat other medical needs may have been causing "an additional death toll [that is] likely to exceed that of the outbreak itself". There were also reports that adequate personal protection equipment was not being provided for medical personnel. The Director-General of MSF said: "Countries affected to date simply do not have the capacity to manage an outbreak of this size and complexity on their own. I urge the international community to provide this support on the most urgent basis possible."

Hospital workers, who worked closely with the highly contagious body fluids of the victims, were especially vulnerable to contracting the virus; in August 2014, the WHO reported that ten percent of the dead had been healthcare workers. In late August, MSF called the situation "chaotic" and the medical response "inadequate." They reported that they had expanded their operations, but couldn't keep up with the rapidly increasing need for assistance, which had forced them to reduce the level of care: "It is not currently possible, for example, to administer intravenous treatments." Calling the situation "an emergency within the emergency", MSF reported that many hospitals had shut down due to a lack of staff or fears of the virus among patients and staff, which had left people with other health problems without any care at all. Speaking from a remote region, an MSF worker said that a shortage of protective equipment was making the medical management of the disease difficult and that they had limited capacity to safely bury bodies.

In September 2014, it was estimated that the affected countries' capacity for treating Ebola patients was insufficient by the equivalent of 2,122 beds. Speaking on 12 September, WHO Director-General, Margaret Chan, said: "In the three hardest hit countries, Guinea, Liberia and Sierra Leone, the number of new cases is moving far faster than the capacity to manage them in the Ebola-specific treatment centres. Today, there is not one single bed available for the treatment of an Ebola patient in the entire country of Liberia." According to a WHO report released on 19 September, Sierra Leone was meeting only 35% of its need for patient beds, while for Liberia it was just 20%.

By December 2014 there were enough beds to treat and isolate all reported cases, although the uneven distribution of cases was resulting in serious shortfalls in some areas. Similarly, all affected countries had sufficient and widespread capacity to bury reported deaths; however, because not all deaths were reported, it was possible that the reverse could have been the case in some areas. WHO also reported that every district had access to a laboratory to confirm cases of Ebola within 24 hours of sample collection and that all three countries had reported that more than 80% of registered contacts associated with known cases of Ebola virus disease were being traced, although contact tracing was still a challenge in areas of intense transmission and those with community resistance.

Healthcare settings

Several Ebola treatment centres were set up in the area, supported by international aid organisations and staffed by a combination of local and international staff. An important part of each centre is an arrangement for the safe burial or cremation of bodies, required to prevent further infection. In January 2015, a new treatment and research centre was built by Rusal and Russia in the city of Kindia in Guinea. It is one of the most modern medical centres in Guinea. Also in January, MSF admitted its first patients to a new treatment centre in Kissy, an Ebola hotspot on the outskirts of Freetown, Sierra Leone. The centre has a maternity unit for pregnant women with the virus.

Although the WHO does not advise caring for Ebola patients at home, in some cases it became a necessity when no hospital treatment beds were available. For those being treated at home, the WHO advised informing the local public health authority and acquiring appropriate training and equipment. UNICEF, USAID and Samaritan's Purse began to take measures to provide support for families that were forced to care for patients at home by supplying caregiver kits intended for interim home-based interventions. The kits included protective clothing, hydration items, medicines, and disinfectant, among other items. Even where hospital beds were available, it was debated whether conventional hospitals are the best place to care for Ebola patients, as the risk of spreading the infection is high. In October, the WHO and non-profit partners launched a program in Liberia to move infected people out of their homes into ad hoc centres that could provide rudimentary care. Health facilities with low-quality systems for preventing infection were involved as sites of amplification during viral outbreaks.

In the hardest hit areas there have historically been only one or two doctors available to treat 100,000 people and these doctors are heavily concentrated in urban areas. Ebola patients' healthcare providers, as well as family and friends, are at highest risk of getting infected because they are more likely to come in direct contact with their blood or body fluids. In some places affected by the outbreak, care may have been provided in clinics with limited resources, and workers could be in these areas for several hours with many Ebola-infected patients. According to the WHO, the high proportion of infected medical staff could be explained by a lack of adequate manpower to manage such a large outbreak, shortages of protective equipment or improper use of what was available, and "the compassion that causes medical staff to work in isolation wards far beyond the number of hours recommended as safe".

Experimental treatments

There is no confirmed medication or treatment for Ebola virus disease. A number of experimental treatments are undergoing clinical trials. During the epidemic some patients received experimental blood transfusions from Ebola survivors, but a later study found that the treatment did not provide significant benefit.

Vaccines

Several Ebola vaccine candidates had been developed in the decade before 2014 and had been shown to protect nonhuman primates against infection, but none had yet been approved for clinical use in humans. About 15 different vaccines were in preclinical stages of development, and there were two phase III studies being conducted with two different vaccines.

In July 2015, researchers announced that a vaccine trial in Guinea had been completed that appeared to give protection from the virus. The vaccine, rVSV-ZEBOV, had shown high efficacy in individuals, but more conclusive evidence was needed regarding its capacity to protect populations through herd immunity. The vaccine trial employed ring vaccination, in which health workers control an outbreak by vaccinating all suspected infected individuals within the surrounding area.

In December 2016, the results of the two-year Guinea trial were published announcing that rVSV-ZEBOV had been found to protect people who had been exposed to cases of Ebola. In addition to showing high efficacy among those vaccinated, the trial also showed that unvaccinated people were indirectly protected from the Ebola virus through herd immunity. The vaccine has not yet had regulatory approval, but it is considered to be so effective that 300,000 doses have already been stockpiled. Not yet known is the length of time that a vaccination will be effective and whether it will prove effective for the Sudan virus.

In April 2018, rVSV-ZEBOV Ebola vaccine was used to stop an outbreak for the first time, the 2018 Équateur province Democratic Republic of the Congo Ebola virus outbreak. In 2019, the rVSV-ZEBOV vaccine received regulatory approval, including from the U.S. FDA.

Outlook

From the beginning of the outbreak, there existed considerable difficulty in getting reliable estimates—both of the number of people affected and of its geographical extent. The three most affected countries—Guinea, Liberia and Sierra Leone—are among the poorest in the world, with extremely low levels of literacy, few hospitals or doctors, low-quality physical infrastructure, and weakly functioning government institutions. One study yielded results of the spatio-temporal evolution of the viral outbreak. With the use of heat maps, it was determined that the outbreak did not uniformly unfold over the affected community areas, indicating that monitoring the outbreak at the district level was important. The study showed that accurate predictions of growth were improbable.

Calculating the case fatality rate (CFR) accurately is difficult in an ongoing epidemic due to differences in testing policies, the inclusion of probable and suspected cases, and the inclusion of new cases that have not run their course. Ebola virus disease has a high CFR, which in past outbreaks varied between 25% and 90%, with an average of about 50%. In August 2014, the WHO made an initial CFR estimate of 53%, though this included suspected cases.

In September and December 2014, the WHO released revised and more accurate CFR figures of 70.8% and 71% respectively, using data from patients with definitive clinical outcomes. The CFR among hospitalised patients, based on the three intense-transmission countries, was between 57% and 59% in January 2015. Care settings that have access to medical expertise may increase survival by providing good maintenance of hydration, circulatory volume, and blood pressure.

The disease affects males and females equally and the majority of those who contract Ebola disease are between 15 and 45 years of age. For those over 45 years, a fatal outcome was more likely in the Western African epidemic, as was also noted in preceding outbreaks. Only rarely do pregnant women survive—a midwife who worked with MSF in a Sierra Leone treatment centre stated that she knew of "no reported cases of pregnant mothers and unborn babies surviving Ebola in Sierra Leone."

The basic reproduction number, R0, is a statistical measure of the average number of people infected by a single infectious individual in a population with no prior immunity. If the basic reproduction number is less than 1, the epidemic will die out; if it is greater than 1, the epidemic will continue to spread—with exponential growth in the number of cases. In September 2014, the estimated values of R0 were 1.71 (95% CI, 1.44 to 2.01) for Guinea, 1.83 (95% CI, 1.72 to 1.94) for Liberia, and 2.02 (95% CI, 1.79 to 2.26) for Sierra Leone.

Projections of future cases

On 28 August 2014, the WHO released its first estimate of the possible total cases from the outbreak as part of its roadmap for stopping the transmission of the virus. It stated: This Roadmap assumes that in many areas of intense transmission, the actual number of cases may be two- to fourfold higher than that currently reported. It acknowledges that the aggregate caseload of Ebola could exceed 20,000 over the course of this emergency. The Roadmap assumes that a rapid escalation of the complementary strategies in intense transmission, resource-constrained areas will allow the comprehensive application of more standard containment strategies within three months. The report included an assumption that some country or countries would pay the required cost of their plan, estimated at half a billion US dollars.

When the WHO released these estimates, a number of epidemiologists presented data to show that the WHO projection of a total of 20,000 cases was likely an underestimate. On 9 September, Jonas Schmidt-Chanasit of the Bernhard Nocht Institute for Tropical Medicine in Germany, controversially announced that the containment fight in Sierra Leone and Liberia had already been "lost" and that the disease would "burn itself out". On 23 September 2014, the WHO revised their previous projection, stating that they expected the number of Ebola cases in Western Africa to be in excess of 20,000 by 2 November 2014. They further stated, that if the disease was not adequately contained it could become native in Guinea, Sierra Leone and Liberia, "spreading as routinely as malaria or the flu", and according to an editorial in the New England Journal of Medicine, eventually to other parts of Africa and beyond.

In a report released on 23 September 2014, the CDC analysed the impact of under-reporting, which required the correction of case numbers by a factor of up to 2.5. With this correction factor, approximately 21,000 total cases were estimated for the end of September 2014 in Liberia and Sierra Leone alone. The same report predicted that total cases, including unreported cases, could reach 1.4 million in Liberia and Sierra Leone by the end of January 2015 if no improvement in intervention or community behaviour occurred. However, at a congressional hearing on 19 November, the Director of the CDC said that the number of Ebola cases was no longer expected to exceed 1 million, moving away from the worst-case scenario that had been previously predicted.

A study published in December 2014 found that transmission of the Ebola virus occurs principally within families, in hospitals, and at funerals. The data, gathered during three weeks of contact tracing in August, showed that the third person in any transmission chain often knew both the first and second person. The authors estimated that between 17% and 70% of cases in Western Africa were unreported—far fewer than had been estimated in prior projections. The study concluded that the epidemic would not be as difficult to control as feared if rapid, vigorous contact tracing and quarantines were employed.

Economic effects

In March 2015, the United Nations Development Group reported that due to a decrease in trade, the closing of borders, flight cancellations, and a drop in foreign investment and tourism activity fuelled by stigma, the epidemic had resulted in vast economic consequences in both the affected areas in Western Africa and other African nations with no cases of Ebola. A September 2014 report in the Financial Times suggested that the economic impact of the Ebola outbreak could kill more people than the disease itself.

Concerning Ebola and economic activity in the country of Liberia, a study found that 8% of automotive firms, 8% of construction firms, 15% of food businesses, and 30% of restaurants had closed due to the Ebola outbreak. Montserrado County experienced up to 20% firm closure. This indicated a decline in the Liberian national economy during the outbreak, as well as an indication that the county of Montserrado was hardest hit economically.

The capital city Monrovia suffered the most construction and restaurant unemployment. Outside the capital, the food and beverage sectors suffered economically. The World Bank had projected an estimated loss of $1.6 billion in productivity for all three affected Western African countries combined for 2015. In Liberian counties that were less affected by the outbreak, the number of individuals employed fell by 24%. Montserrado saw a 47% decline in employment per firm from before the Ebola outbreak.

Another study showed that the economic effect of the Ebola outbreak would be felt for years due to preexisting social vulnerability. The economic effects were being felt nationwide in Liberia, such as the termination of expansions in the mining business. Initial scenarios had placed expected economic losses at $25 billion. Subsequent World Bank estimates were much lower, at about 12% of the combined GDP of the three worst hit countries.

Despite the end of civil violence in 2003 and inflows from international donors, the reconstruction of Liberia had been very slow and non-productive—water delivery systems, sanitation facilities, and centralised electricity were practically non-existent, even in Monrovia. Even before the outbreak, medical facilities did not have potable water, lighting, or refrigeration. The authors indicated that lack of food and other economic effects would probably continue in the rural population long after the Ebola outbreak had ended.

Responses

In July 2014, the WHO convened an emergency meeting of health ministers from eleven countries and announced collaboration on a strategy to coordinate technical support to combat the epidemic. In August they published a road map to guide and coordinate the international response to the outbreak, aiming to stop ongoing Ebola transmission worldwide within 6–9 months, and formally designated the outbreak as a Public Health Emergency of International Concern. This is a legal designation used only twice before (for the 2009 H1N1 (swine flu) pandemic and the 2014 resurgence of poliomyelitis) that invokes legal measures on disease prevention, surveillance, control, and response, by 194 signatory countries.

In September 2014, the United Nations Security Council declared the Ebola virus outbreak in Western Africa "a threat to international peace and security" and unanimously adopted a resolution urging UN member states to provide more resources to fight the outbreak. In October, WHO and the UN Mission for Ebola Emergency Response announced a comprehensive 90-day plan to control and reverse the Ebola epidemic. The ultimate goal was to have capacity in place for the isolation of 100% of Ebola cases and the safe burial of 100% of casualties by 1 January 2015 (the 90-day target). Many nations and charitable organisations cooperated to realise the plan, and a WHO situation report published mid-December indicated that the international community was on track to meet the 90-day target.

On 5 November 2014, Australian Prime Minister Tony Abbott announced that Australian health services company Aspen Medical would be staffing a 100-bed hospital in Sierra Leone after an agreement was reached with the United Kingdom to treat any infected Australian workers.

From 2014 to 2015, China's People's Liberation Army deployed 524 medical staff on a rotational basis to combat the outbreak in Liberia, Sierra Leone, Guinea, and Guinea-Bissau.

In May 2015, Dr. Margaret Chan indicated, "demands on WHO was more than ten times greater than ever experienced in the almost 70-year history of this Organization" and on 23 March, she stated that "the world remains woefully ill-prepared to respond to outbreaks that are both severe and sustained."

Criticism of WHO

The WHO has been widely criticised for its delay in taking action to address the epidemic. By September 2014, Médecins Sans Frontières/Doctors Without Borders (MSF), the non-governmental organisation with the largest working presence in the affected countries, had grown increasingly critical of the international response. Speaking on 3 September, the International President of MSF spoke out concerning the lack of assistance from United Nations (UN) member countries: "Six months into the worst Ebola epidemic in history, the world is losing the battle to contain it."

In a 26 September statement, the WHO stated that "[t]he Ebola epidemic ravaging parts of Western Africa is the most severe acute public health emergency seen in modern times" and its Director-General called the outbreak "the largest, most complex and most severe we've ever seen". In October 2014, the Associated Press reported in an internal draft document that the WHO admitted "nearly everyone" involved in the Ebola response failed to notice factors that turned the outbreak into the largest on record, and that they had missed chances to stop the spread of Ebola due to "incompetent staff, bureaucracy and a lack of reliable information".

Peter Piot, co-discoverer of the Ebola virus, called the WHO regional office in Africa "really not competent." In April 2015, the WHO admitted very serious failings in handling the crisis and indicated reforms for any future crises; "we did not work effectively in coordination with other partners, there were shortcomings in risk communications and there was confusion of roles and responsibilities". The Ebola crisis was discussed at the June 2015 G7 meeting. The leaders pledged to assist in carrying out WHO regulations. Critics criticised the G7 leaders, saying they were not committed enough in the fight against the possibility of future pandemics.

In 2015, a panel of experts looked at the ways of preventing small outbreaks from becoming large epidemics. According to the panel, the epidemic had exposed problems in the national and international institutions responsible for protecting the public from the human consequences of infectious disease outbreaks such as the Ebola epidemic. The panel was highly critical of the WHO's management of the Ebola crisis noting that it took them months to respond and when they did they were slow to act, poorly co-ordinated and inadequately informed.

The report pointed out that the committee responsible for checking the WHO's actions during the outbreak (i.e. the WHO Ebola Interim Assessment Panel) had delayed responses due to worries about political resistance from the Western African leaders, economic consequences, and a system within the WHO that discouraged open debate about issues such as emergency declarations. The WHO may also have hesitated because it was criticised for creating panic by declaring a public health emergency during the relatively mild 2009 H1N1 pandemic. This, the report states, showed the risks of having such consequential decision-making power in one individual—a risk made worse when there was no mechanism of responsibility for such leadership failure.

Notable patients

Patrick Sawyer—index case for Nigeria; died on 24 July 2014.

Sheik Umar Khan—Sierra Leonean doctor, died on 29 July 2014.

Ameyo Adadevoh—curbed spread of the virus in Nigeria; died on 19 August 2014.

Thomas Eric Duncan—first Ebola patient diagnosed in U.S.; died on 8 October 2014.

Salome Karwah—survived Ebola in 2014 and became a nurse; named co-Person of the Year by Time magazine.

Ian Crozier—contracted the disease in September 2014, and was treated at Emory University from 9 September to 19 October of that year.

Pauline Cafferkey—A British nurse and aid worker, infected in 2014, recovered but was subsequently readmitted to the hospital several times.

Samuel Brisbane—a former adviser to the Liberian Ministry of Health and Social Welfare, described as "one of Liberia's most high-profile doctors".

Mbalu Fonnie—a licensed nurse-midwife and nursing supervisor at the Kenema hospital in Sierra Leone who died after contracting Ebola while caring for a fellow nurse who was pregnant and had the disease.