Ebola vaccines are vaccines either approved or in development to prevent Ebola. The first vaccine to be approved in the United States was rVSV-ZEBOV in December 2019It had been used extensively in the Kivu Ebola epidemic under a compassionate use protocol. During the early 21st century, several vaccine candidates displayed efficacy to protect nonhuman primates against lethal infection.

An immune response is a reaction which occurs within an organism for the purpose of defending against foreign invaders. These invaders include a wide variety of different microorganisms including viruses, bacteria, parasites, and fungi which could cause serious problems to the health of the host organism if not cleared from the body. There are two distinct aspects of the immune response, the innate and the adaptive, which work together to protect against pathogens. The innate branch-the body's first reaction to an invader-is known to be a non-specific and quick response to any sort of pathogen. Components of the innate immune response include physical barriers like the skin and mucous membranes, immune cells such as neutrophils, macrophages, and monocytes, and soluble factors including cytokines and complement. On the other hand, the adaptive branch is the body's immune response which is catered against specific antigens and thus, it takes longer to activate the components involved. The adaptive branch include cells such as dendritic cells, T cell, and B cells as well as antibodies-also known as immunoglobulins—which directly interact with antigen and are a very important component for a strong response against an invader.

The Kivu Ebola epidemic was an outbreak of Ebola virus disease (EVD) that ravaged the eastern Democratic Republic of the Congo in Central Africa from 2018 to 2020. Between 1 August 2018 and 25 June 2020 it resulted in 3,470 reported cases. The Kivu outbreak also affected Ituri Province, whose first case was confirmed on 13 August 2018. In November 2018, the outbreak became the biggest Ebola outbreak in the DRC's history, and had become the second-largest Ebola outbreak in recorded history worldwide, behind only the 2013–2016 Western Africa epidemic. In June 2019, the virus reached Uganda, having infected a 5-year-old Congolese boy who entered Uganda with his family, but was contained.

Ebola, also known as Ebola virus disease and Ebola hemorrhagic fever, is a viral hemorrhagic fever in humans and other primates, caused by Ebola viruses. Symptoms typically start anywhere between two days and three weeks after becoming infected with the virus. The first symptoms are usually fever, sore throat, muscle pain, and headaches. These are usually followed by vomiting, diarrhea, rash and decreased liver and kidney function, at which point, some people begin to bleed both internally and externally. The disease kills between 25% and 90% of those infected—about 50% on average. Death is often due to shock from fluid loss, and typically occurs between six and 16 days after the first symptoms appear.

Each species of the genus Ebola virus has one member virus, and four of these cause Ebola virus disease in humans, a type of hemorrhagic fever having a very high case fatality rate. The Reston virus has caused EVD in other primates. Zaire Ebola virus has the highest mortality rate of the Ebola viruses and is responsible for the largest number of outbreaks of the six known species of the genus, including the 1976 Zaire outbreak and the outbreak with the most deaths.