Less than one week after cases of Ebola were confirmed to have reached an urban area the Democratic Republic of Congo (DRC), health authorities, led by the World Health Organization, began a new effort to control the outbreak [1]. For the first time, a vaccine is being used in an effort to control an Ebola outbreak.
Concerns about the current outbreak were solidified when a new case of Ebola was confirmed in Mbandaka, a city of approximately 1.2 million people [2]. Previously, the cases had been identified only in a rural area. As of May 27th, there have been 19 suspected or probable cases and 35 confirmed cases of Ebola in the DRC [3]. 25 deaths have been reported from this outbreak. The majority of cases have been reported in Iboka and Bikoro, both rural areas, while four cases have been confirmed in Mbandaka [3].
While there are a few Ebola vaccines in the testing stages by pharmaceutical companies, Merck’s rVSV-EBOV was chosen by WHO to be the one used in this campaign [4,5]. The vaccine is not currently licensed, but clinical trials conducted in Guinea in 2016 found that vaccine was 100% effective [6]. Development of an Ebola vaccine began in the early 2000s but didn’t move to a clinical trial phase due to a lack of both funding and the rarity of the disease [5]. However, interest in continued development for an Ebola vaccine picked up again after the 2014 outbreak in West Africa, in which more than 11,300 people died [7].
The Ministry of Health in DRC has implemented a ring vaccination campaign, the same method used to control smallpox [4,8]. Last Monday, healthcare workers in Mbandaka became the first to receive the vaccine [7]. After healthcare workers are vaccinated, efforts will shift toward those who came in contact with confirmed cases, as well as contacts of contacts [4]. The campaign will also move into the Bikoro and Iboko health zones [7]. Merck has donated the vaccines for this campaign, and more than $4 million USD has been donated for operational costs by Gavi, the Vaccine Alliance, the British and US governments, and the Wellcome Trust [4,7,9].
There are a few challenges associated with implementing this vaccination campaign. First, the vaccine must be stored between -60 and -80 degrees Celsius [4]. WHO has provided special carriers which are able to keep vaccines at the appropriate temperatures for up to a week and have also set up freezers in Bikoro and Mbandaka for vaccine storage. Additionally, transportation infrastructure in the DRC is limited, with some areas only accessible by motorbike [10]. WHO hopes to establish an air bridge to bring the supplies to more remote areas via helicopter.
Despite these challenges, WHO is confident that the use of vaccines will represent a “paradigm shift” in the fight against Ebola [11]. WHO Director-General Dr Tedros Adhanom Ghebreyesus believes that "vaccination will be key to controlling this outbreak" [4].
Sources
[1] http://www.cbc.ca/news/health/ebola-vaccine-congo-1.4665655
[3] http://www.who.int/ebola/situation-reports/drc-2018/en/
[6] https://www.scientificamerican.com/article/everything-you-need-to-know-about-the-ebola-vaccine/
[7] https://www.washingtonpost.com/world/africa/nurse-dead-in-congo-as-ebola-vaccination-campaign-starts/2018/05/21/1b71082e-5ce7-11e8-b656-236c6214ef01_story.html?utm_term=.45139fb376f2
[8] https://www.cdc.gov/smallpox/bioterrorism-response-planning/public-health/ring-vaccination.html
[10] https://www.statnews.com/2018/05/11/who-merck-ebola-vaccine-congo/
