World’s First Effective Ebola Vaccine Launched

The 2014 outbreak of Ebola in West Africa was the deadliest since the disease’s discovery nearly four decades ago. Though the outbreak caused over 11,000 deaths over the course of more than two years, there is now hope of an effective vaccine. The World Health Organization (WHO) developed and tested an Ebola vaccine that could prevent future outbreaks. Learn about this groundbreaking Ebola vaccine and how it could benefit at-risk populations around the world.

Origins of the Ebola Vaccine

 

Vaccination bottles.

Image via Flickr by Carlos Reusser Monsálvez

Though the deadly 2014 Ebola outbreak is credited for prompting researchers to create an effective vaccine against the disease, scientists have been working for decades to develop protection from Ebola. According to the New York Times, scientists have pursued several ultimately unsuccessful efforts at creating a vaccine since the disease emerged in the former Zaire in 1976. Despite over 1,500 Ebola-related deaths and reports of the devastating symptoms, Ebola vaccination developments stalled time and time again. In fact, by 2005, a group of North American researchers had developed and tested a vaccine that proved completely effective against Ebola in monkeys. Though the scientists suggested a five-year timeline for human testing and product licensing, developments stopped shortly after the initial announcement. Sometimes, the relative rarity of a disease works against it. In this case, because Ebola was considered somewhat rare and its outbreaks relatively limited, neither effort nor funding pushed for the release of the Ebola vaccine.

Ebola Outbreak Prompts Renewed Vaccination Testing

Until 2014, the Ebola virus had killed an average of fewer than 50 people per year. When the outbreak began to spread in West Africa, however, the number of both reported cases and deaths quickly skyrocketed. As the nearly 30,000 reported cases spread to five African countries and the United States, researchers revisited earlier Ebola research and restarted long-delayed tests and trials. As the New York Times reports, the vaccine featured in these tests was the one originally developed by the Public Health Agency of Canada and the United States Army in 2005. According to the WHO, vaccination trials took place in Guinea’s coastal Basse-Guinée region and included more than 11,000 test subjects, nearly 6,000 of whom received the test vaccine. When testing began in 2015, this area was still experiencing a moderate level of new Ebola cases. To select test subjects, WHO-led researchers monitored the area for new Ebola cases. When one emerged, researchers identified people who had been in close contact with the afflicted patients or their clothing within three weeks prior to diagnosis. On average, these groups numbered about 80 people, with 117 total groups, or rings. Researchers then randomized the rings, with some subjects receiving the vaccine right away or after a three-week delay. Though only adults over 18 received the vaccination at first, positive preliminary results led researchers to administer the vaccine immediately to all subjects over 6 years old. Among those who received the test vaccine, none contracted Ebola 10 or more days afterward. In contrast, 23 people who did not receive the test vaccine reported cases of Ebola within the same time frame. These results suggest that the vaccine is completely effective against Ebola. Ultimately, the trials reported no long-term effects from the Ebola vaccine. According to WHO, about half of the subjects reported mild symptoms like headaches and fatigue, but these dissipated quickly. Just one anaphylaxis reaction emerged from the study, but the subject did not have long-term effects.

Next Steps for the Ebola Vaccine

Though testing started and finished during the Ebola outbreak in West Africa, lengthy regulatory and licensing processes mean that the vaccine was not available to patients afflicted at that time. However, continued developments mean that the Ebola vaccine may soon be available. In the past, limited funding prevented the development process from moving forward, but $5 million in funding from Gavi, the Vaccine Alliance, suggests an optimistic conclusion to the testing process. This funding is designed to help Merck procure the vaccine once WHO approves and recommends it, and Merck has agreed to make 300,000 doses available for emergency use. The pharmaceutical company has also committed to moving forward with the vaccine licensing process by the end of 2017. In addition, further research may be required to provide even more robust Ebola vaccine options. While the vaccine currently under development targets the most common strain of Ebola, five subtypes of the disease exist. The New York Times reports that the current vaccine is not effective against all five subtypes, and a comprehensive vaccine based on the existing model would likely cause unacceptable side effects. While the vaccine offers an effective solution now, it may not ultimately eradicate Ebola.

Lessons Learned From the Ebola Vaccine

Sometimes, vaccines arrive too late to save the people who need them most. Since earlier attempts to test and produce an Ebola vaccine were not complete in time to save the 11,000 victims of the 2014 outbreak, researchers have taken steps to ensure that this doesn’t happen again. Though the vaccine is not yet licensed, it is part of the WHO’s Emergency Use and Assessment Listing, which means it could be used in case of another outbreak. In fact, as Nature reports, a 2017 outbreak in the Democratic Republic of the Congo (DRC) has prompted additional review of the vaccine. WHO and DRC government officials continue to assess whether the benefit of stamping out the relatively limited number of Ebola cases outweighs the cost of deploying the vaccine. Vaccines have the potential to save lives, and a career in public health may enable you to educate populations in need about the widespread benefits of these immunizations. Visit the Keck School of Medicine of USC to learn more about the online MPH program that could inspire you to make a positive difference in your community or around the globe. Sources: http://www.who.int/features/2017/ebola-guinea-photos/en/ http://www.who.int/mediacentre/news/releases/2016/ebola-vaccine-results/en/ https://www.nytimes.com/2016/12/22/health/ebola-vaccine.html https://www.nytimes.com/2014/10/24/health/without-lucrative-market-potential-ebola-vaccine-was-shelved-for-years.html https://www.nature.com/news/ebola-vaccine-approved-for-use-in-ongoing-outbreak-1.22024