What is Ebola?

The Ebola virus disease (EVD), is a severe, and often fatal, disease.

The Ebola virus first emerged in 1976 with two simultaneous outbreaks in Nzara, Sudan and Yambuku, Democratic Republic of Congo, near tropical forests.

Ebola viruses belong to the Filoviridae family and cause Ebola Viral Disease (EVD), which can induce severe hemorrhagic fever in humans and non-human primates (NHPs). Patients with EVD have a mortality rate ranging from 50% to 90% according to the World Health Organization (WHO).

How is it transmitted?

It’s transmitted from wild animals to people. It then spreads among humans via direct contact through broken skin or mucous membranes with the blood, secretions, organs or other bodily fluids of infected people and with surfaces and materials (e.g. bedding, clothing) contaminated with these fluids. www.who.int

What is the status of the current epidemic?

The 2014–2016 outbreak in West Africa was the largest Ebola outbreak since the virus was first discovered in 1976. The outbreak started in Guinea and then moved across land borders to Sierra Leone and Liberia. After an initial declaration in November 2015, Sierra Leone announced a new case of EVD in January 2016 and declared it was Ebola-free on March 17, 2016. In Guinea, the first end of outbreak declaration was in December 2015, but additional cases were discovered in March and April of 2016. Guinea was finally declared Ebola-free in June 2016. Two and a half years after the first case was discovered, the outbreak ended with more than 28,600 cases and 11,325 deaths.

The 10th outbreak occurred from 2018-2020 in eastern Democratic Republic of the Congo (DRC) and was highly complex, with insecurity adversely affecting public health response activities. The 10th Ebola outbreak was declared over on 25th June 2020. From 1 August 2018 to 25 June 2020, a total of 3470 EVD cases were reported from 29 health zones including 3317 confirmed cases and 153 probable cases. Of the total confirmed and probable cases, 57% (n=1974) were female, 29% (n=1006) were children aged less than 18 years and 5% (n=171) were health care workers.

The Democratic Republic of the Congo’s 11th Ebola virus disease (EVD) outbreak was announced on 1 June 2020 after a cluster of cases was detected in the Mbandaka area of Équateur Province. The WHO regional office for Africa reported on 25 July 2020, that there were a total of 67 cases (63 confirmed and four probable) including 31 deaths (case fatality ratio 46.3%). The 11th Ebola outbreak in Equateur Province was declared over on 18th November 2020.

The 12th EVD outbreak in the DRC was declared on 7 February 2021. On 3 May 2021, the Minister of Health of the DRC declared the end of the EVD outbreak that affected four health zones Biena, Musienene, Katwa, and Butembo within North Kivu province. Overall, 12 cases were reported (11 confirmed and 1 probable). Of these 12 cases, eight (73%) were known and followed contacts at time of detection, and all were linked epidemiologically within a unique chain of transmission.

From www.who.int, WHO report – 26 June 2020 and WHO regional office for Africa -25 July 2020 https://www.cdc.gov/vhf/ebola/history/2014-2016-outbreak/index.html

What are the symptoms of Ebola?

The incubation period is 2 to 21 days. Initial symptoms include fever, fatigue, muscle, pain, headache and sore throat. This is followed by vomiting, diarrhea, rash, symptoms of impaired kidney and liver function, and in some cases, both internal and external bleeding. The average case fatality rate ranges from 25% to 90%. In the current epidemic, an average of 36% of cases are fatal. In Guinea, however, 60% of cases end in death, while in Liberia and Sierra Leone, the rate is 42% and 22% respectively.

What are the possible treatments for Ebola?

Supportive care-rehydration with oral or intravenous fluids- and treatment of specific symptoms, improves survival. There is as yet no proven treatment available for EVD. However, a range of potential treatments including blood products, immune therapies and drug therapies are currently being evaluated. No licensed vaccines are available yet, but potential vaccines are undergoing or will soon undergo human safety testing.

Is a vaccine available?

On December 19th, 2019, the FDA announced approval of Merck & Co.’s Ervebo vaccine, the first FDA-approved vaccine for the prevention of Ebola virus disease. Additionally, the Janssen Ebola vaccine regimen received marketing authorization by the European Medicines Agency (EMA) in July 2020.

What is the approach for developing the Janssen Ebola vaccine regimen?

The monovalent vaccine based on adenovirus type 26 (Ad26) vector expressing the glycoprotein (GP) of the Ebola virus Mayinga variant (Ad26.ZEBOV) was developed by the Sponsor (Janssen Vaccines & Prevention B.V.), as well as the multivalent Modified Vaccinia Virus Ankara (MVA) strain containing ZEBOV, SEBOV, Marburg Virus GP and Tai Forest nucleoprotein inserts (MVA-BN®-Filo). These candidate vaccines will be used in a heterologous two-dose vaccine regimen in which one vector is used to prime a filovirus-specific immune response and the other vector is used to boost the immune response four to 12 weeks later. Janssen Ebola vaccine regimen received marketing authorization by the European Medicines Agency (EMA) on 1July2020.