Ebola vaccine

The Ebola vaccine is a vaccine used to prevent Ebola virus disease, a severe and often fatal illness in humans caused by the Ebola virus. The development of an effective vaccine has been a significant public health priority, especially following the 2014-2016 Ebola outbreak in West Africa.

Development and Approval

The first Ebola vaccine to be approved was Ervebo, developed by Merck. It is a recombinant, replication-competent vaccine that uses a vesicular stomatitis virus (VSV) as a vector to express a glycoprotein from the Zaire ebolavirus. This vaccine was approved by the European Medicines Agency (EMA) in November 2019 and by the U.S. Food and Drug Administration (FDA) in December 2019.

Electron micrograph of Ebola virions.

The vaccine was initially tested in clinical trials during the 2014-2016 outbreak, where it demonstrated high efficacy in preventing Ebola virus disease. The vaccine is administered as a single dose and is recommended for individuals at high risk of exposure, such as healthcare workers and those in outbreak areas.

Mechanism of Action

The Ebola vaccine works by using a viral vector to deliver a piece of the Ebola virus's genetic material into the body. This genetic material codes for the Ebola virus glycoprotein, which is expressed on the surface of the vector virus. The immune system recognizes this glycoprotein as foreign and mounts an immune response, producing antibodies and activating T-cells that can recognize and destroy the Ebola virus if the vaccinated individual is exposed in the future.

Diagram of recombinant DNA technology used in vaccine development.

Types of Ebola Vaccines

There are several types of Ebola vaccines under development or in use:

• Ervebo (rVSV-ZEBOV): A live attenuated vaccine using the VSV vector.
• Zabdeno and Mvabea: A two-dose regimen developed by Johnson & Johnson, using an adenovirus vector for the first dose and a modified vaccinia Ankara (MVA) vector for the second dose.

Challenges and Future Directions

While the development of the Ebola vaccine has been a major success, challenges remain. These include ensuring widespread access to the vaccine in affected regions, maintaining cold chain logistics for vaccine storage, and continuing research to improve vaccine efficacy and safety.

Also see

• Ebola virus disease
• Viral vector vaccine
• Vaccine development
• Public health