RVSV-ZEBOV-GP

rVSV-ZEBOV-GP, also known by its trade name Ervebo, is a vaccine used to prevent Ebola virus disease caused by the Zaire ebolavirus. It is a recombinant, replication-competent vaccine that uses a vesicular stomatitis virus (VSV) backbone, into which the glycoprotein (GP) of the Zaire ebolavirus has been inserted.

Development and Approval

The development of rVSV-ZEBOV-GP was a collaborative effort involving multiple organizations, including the Public Health Agency of Canada, which initially developed the vaccine, and Merck & Co., which later acquired the rights to further develop and commercialize it. The vaccine underwent extensive clinical trials in West Africa during the 2014–2016 Ebola outbreak.

In November 2019, the European Medicines Agency (EMA) recommended granting a conditional marketing authorization for Ervebo, and it was subsequently approved by the European Commission. In December 2019, the U.S. Food and Drug Administration (FDA) approved Ervebo for use in individuals 18 years of age and older.

Mechanism of Action

The rVSV-ZEBOV-GP vaccine works by using a live attenuated virus, the vesicular stomatitis virus, which has been genetically engineered to express the glycoprotein of the Zaire ebolavirus. This glycoprotein is the primary antigen that elicits an immune response in the vaccinated individual. When administered, the vaccine stimulates the immune system to produce antibodies against the Ebola virus, providing protection against future infections.

Clinical Trials and Efficacy

Clinical trials conducted in Guinea during the 2014–2016 Ebola outbreak demonstrated that rVSV-ZEBOV-GP was highly effective in preventing Ebola virus disease. The vaccine was administered using a "ring vaccination" strategy, where contacts and contacts of contacts of confirmed Ebola cases were vaccinated. This approach was shown to be 100% effective in preventing Ebola virus disease in those who received the vaccine.

Safety and Side Effects

The rVSV-ZEBOV-GP vaccine is generally well-tolerated. Common side effects include pain at the injection site, headache, fatigue, fever, and muscle pain. These side effects are typically mild to moderate in intensity and resolve within a few days. Serious adverse events are rare.

Distribution and Use

The rVSV-ZEBOV-GP vaccine has been used in outbreak settings to control the spread of Ebola virus disease. It is particularly useful in emergency situations due to its rapid onset of immunity and the ability to be used in a ring vaccination strategy. The vaccine is stored at -80°C, which poses logistical challenges in resource-limited settings.

Also see

• Ebola virus disease
• Zaire ebolavirus
• Vesicular stomatitis virus
• Ring vaccination
• 2014–2016 Ebola outbreak