Ebola vaccine study results published: 100% protection in Ebola challenged rhesus macaques

Yesterday, GeoVax Labs, Inc. announced the publication of its manuscript entitled “A Single-Dose of Modified Vaccinia Ankara Expressing Ebola Virus Like Particles Protects Nonhuman Primates from Lethal Ebola Virus Challenge” in the peer-reviewed open access journal Scientific Reports by Nature Research, which shows that a single intramuscular (IM) dose of GeoVax’s Ebola vaccine (GEO-EM01) provided 100% protection in rhesus macaques challenged with a lethal dose of Ebola virus (EBOV).

GEO-EM01 is based on the Company’s novel Modified Vaccinia Ankara (MVA) Virus-Like Particle (VLP) platform, which generates noninfectious VLPs in the individual being vaccinated. VLPs mimic a natural infection, triggering the body to produce a robust and durable immune response with both antibodies and T cells.

This is the first report that a replication-deficient MVA vector can confer full protection against a lethal EBOV challenge after a single-dose vaccination in macaques.

In this study, GEO-EM01 was administered as either a single IM inoculation (prime) or as two IM inoculations at a four-week interval (prime-boost) to groups of four rhesus macaques each. A control group received the MVA vector without Ebola virus protein inserts. Four weeks after inoculation, animals in all three groups were exposed to a lethal dose of Ebola virus. Three of the four unvaccinated animals died within 12 days, while all of the vaccinated animals survived. Researchers at Rocky Mountain Laboratories, part of the National Institute of Allergy and Infectious Diseases (NIAID), collaborated in the study.

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GEO-EM01 is one component of a tetravalent hemorrhagic fever virus vaccine being developed by GeoVax. The other vaccine components are for protection against Sudan virus (SUDV), Marburg virus (MARV), and Lassa virus (LASV). These vaccines are envisioned as either individual monovalent vaccines in epidemic situations or combined as a tetravalent vaccine for the protection of the millions of individuals who live in at-risk areas, travelers, military personnel, healthcare workers, and others.

Farshad Guirakhoo, PhD, GeoVax’s Chief Scientific Officer, commented, “GEO-EM01 uses GeoVax’s proven MVA-VLP vaccine platform that has been shown to be safe and to induce durable antibody and T-cell responses in multiple human clinical trials for GeoVax’s prophylactic HIV vaccine. Using the same platform, we have shown our Zika vaccine (GEO-ZM02) and our Lassa Fever vaccine (GEO-LM01) to provide single-dose 100% protection in mice against intracranial challenge. This study is unique because the immune response induced after a single dose of the vaccine not only provided full protection against a lethal challenge, but also eliminated the wild type Ebola challenge virus from the animal’s blood. No live virus could be recovered at any time point from any of the vaccinated animals compared to the controls, which had more than 100,000 live Ebola viruses per ml of blood.”





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