Vaccine and new drugs for Ebola virus are effective

Dr. Melvin Sanicas
Aug 20, 2019 · 3 min read
3D medical animation of Ebola virus. Image credits: Scientific Animations.

Ebola virus disease (EVD), formerly known as Ebola haemorrhagic fever, is a rare but severe, often fatal illness in humans. The virus is transmitted to people from wild animals and spreads in the human population through human-to-human transmission. The average EVD case fatality rate is around 50%. Case fatality rates have varied from 25% to 90% in past outbreaks.

It was recently reported that Ebola may now be curable as the first-ever multi-drug randomized trial for Ebola has proven extremely successful. The Pamoja Tulinde Maisha (meaning “together save lives”) study is a randomized, controlled trial of four investigational agents (ZMapp, remdesivir, mAb114 and REGN-EB3) for the treatment of patients with Ebola virus disease. As of August 9, 2019, the trial had enrolled 681 patients toward an enrollment total of 725. Patients were enrolled at four Ebola Treatment Centers (ETCs) in Beni, Katwa, Butembo and Mangina. The survival rate for people who received either drug shortly after infection, when levels of the virus in their blood were low, was 90%.

EGN-EB3, is a cocktail of three monoclonal antibodies against Ebola made by Regeneron Pharmaceuticals of Tarrytown, New York. The second, mAB114, is derived from a single antibody recovered from the blood of a person who survived Ebola in the DRC in 1995 and was developed by the US National Institute of Allergy and Infectious Diseases (NIAID). Both drugs outperformed two other experimental treatments in the multi-drug clinical trial in the DRC, according to the World Health Organization, Institut National de Recherche Biomédicale (INRB) and NIAID.

“From now on we will no longer say that Ebola is not curable. This advance will in the future help save thousands of lives that would have had a fatal outcome in the past,” Jean-Jacques Muyembe, Director general of the DR Congo’s Institut National de Recherche Biomedicale.

Ebola vaccine is 97.5% effective, protecting over 90K people.

Earlier this year, it was also reported that the Ebola vaccine (rVSV-ZEBOV-GP Ebola vaccine) tested in Africa was found to be 97.5% effective. Only 8.8% (60/679) of the vaccinated rings reported Ebola cases, and only 2.2% (15/679) reported Ebola cases 10 days or more after vaccination. Most cases among vaccinated people (76%, 54/71) occurred among high-risk contacts. Only 2 out of 68,279 vaccinated contacts of contacts developed Ebola. This indicates that the ring vaccination has an effect in preventing tertiary generation of cases. The estimated Ebola attack rate for vaccinated individuals was about 0.017%, compared with an estimated 0.656 % in unvaccinated individuals.

Ebola Virus Disease Democratic Republic of Congo: External Situation Report 54 / 2019

Ebola first emerged over 4 decades ago but it sparked global fear after massive outbreaks in West Africa between 2014 and 2016 that killed over 11,300 people. Smaller outbreaks have continued, including the ongoing crisis in DR Congo where 2,800 people have been diagnosed and more than 1,800 people have died.

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