Ebola Zaire vaccine (live, attenuated)

Specification

• Cat#: VZV-422
• Product Name: Ebola Zaire vaccine (live, attenuated)
• Description: Ebola virus vaccine is a vaccine used to prevent Ebola virus disease caused by Zaire ebolavirus in adults, prevent outbreaks, and reduce the extent of the virus spreading in case of outbreaks.6 Ebola virus disease, formerly known as Ebola hemorrhagic fever, is a rare but severe and often deadly disease. It is highly contagious: human to human transmission occurs from contact with body fluids from infected patients.4 It is characterized by fever, headache, myalgia, and gastrointestinal symptoms. These may be accompanied by hypotension and respiratory, kidney and liver failure, as well as internal and external bleeding.1,2 In the Filoviridae family, there are five unique Ebolavirus species that are each named after the geographical region where it was first identified. The mortality rate of the Zaire species is about 80%.2Confirmed outbreaks of Ebola virus disease have been documented since the 1970s, mostly in Sub-Saharan Africa, where Ebola first appeared in 1976 near the Ebola River in Zaire (presently referred to as the Democratic Republic of the Congo) and Sudan.1 Between 2014 and 2016, Ebola outbreaks occurred in West Africa, leading to more than 11,310 total deaths during this time in Guinea, Liberia, and Sierra Leone.2 In 2016, this epidemic was exhausted after these countries were declared Ebola-free by 2016, and the World Health Organization (WHO) lifted the Public Health Emergency of International Concern (PHEIC) status on the West Africa Ebola outbreak.9The first live, attenuated Ebola virus vaccine was developed by a team of Canadian researchers at Canada’s National Microbiology Laboratory and was later patented by the Canadian government.8 In non-human primate clinical trials, the vaccine was effective in inducing an immune response against the Ebola viruses.3 This vaccine was later sold to NewLink Genetics, a biotech company that held the license to the vaccine from 2010 to 2014, although the vaccine was not marketed.8 In 2014, Merck Inc. signed a licensing agreement with NewLink for further development and marketing. Ervebo, the marketed Ebola virus vaccine by Merck, was first approved by the European Commission in November 2019 after the European Medicines Agency recommended it be licensed. In December 2019, Ervebo was approved by the FDA in the United States. Ervebo consists of an envelope glycoprotein of the Zaire ebolavirus (Kikwit 1995 strain) fused into a vesicular stomatitis virus (VSV) backbone.6 By introducing the relatively inactive viral protein to the patient, the patient’s immune system learns to recognize and attack the virus if he or she is exposed to it in the future.
• Species: Ebola Virus
• Biologic Classification: Vaccines Attenuated

Pharmaceutical Information

• Pharmacodynamics: As with other live attenuated vaccines, Ebola virus vaccine is speculated to undergo nonspecific cellular degradation.
• Mechanism of action: Ebola virus disease occurs when the virus comes into contact with the host tissue and invades the tissue by breaking in the mucosa or skin. Exposure can occur through animal-to-human or human-to-human transmission from blood and other bodily fluids of the virus-infected animal or human.4 The viral genome then replicates inside the cell, causing gene modulation in host cells - including monocytes, macrophages, and dendritic cells - and promote cell apoptosis, releasing the viral particles to extracellular tissue.2 The virus can further disseminate the infection by migrating to the regional lymph nodes, liver, and spleen to cause lymphadenopathy, hepatocellular necrosis, and lymphopenia.2,4 Ebola virus can cause dysregulation of the host immune system by inducing the host expression and release of pro-inflammatory mediators, including interferons, interleukins (IL-2, IL- 6, IL-8, and IL-10), and tumour necrosis factor α (TNF-α).4 These inflammatory processes promote endothelial activation and reduced vascular integrity. Furthermore, the release of tissue factors and increased nitric oxide levels lead to disseminated intravascular coagulation (DIC) and hypotension seen in the Ebola virus disease, respectively.2,4 The incubation period after the Ebola virus infection is 1-21 days.4By introducing the attenuated viral protein to the patient, the Ebola Zaire vaccine elicits strong cellular and antibody responses against the virus. The vaccine produces a long-term immunity and protects the patient from Ebola virus infection and disease when he or she is exposed to Zaire ebolavirus in the future.5 However, the relative contributions of innate, humoral and cell-mediated immunity to protection from Zaire ebolavirus is not fully understood.6