Frequently asked questions on Ebola virus disease vaccine

WHO:  1. Is there a vaccine for Ebola virus disease?

An experimental Ebola vaccine has shown to be highly protective against the Ebola virus. This product, called rVSV-ZEBOV. It was studied in several trials that involved more than 16,000 volunteers in Europe, Africa and the United States and has been judged safe for use in humans based on available results. In Guinea, the vaccine was tested in 7,500 adults in 2015 and found safe and protective against Ebola infection. This trial was conducted by WHO, with the Guinean Ministry of Health, Doctors Without Borders and the Norwegian Institute of Public Health, in collaboration with other international partners.
The Ebola vaccine, that has the technical name rVSVΔG-ZEBOV- GP, was developed by the Public Health Agency of Canada, licensed to NewLink Genetics, who in turn licensed it to Merck & Co. The vaccine works by replacing a gene from a harmless virus known as vesicular stomatitis virus (VSV) with a gene encoding an Ebola virus surface protein. The vaccine does not contain any live Ebola virus.

2. Is now the right time to use the candidate vaccine in DRC?

• The current outbreak is due to the Ebola Zaire. Strategic Advisory Group of Experts on Immunization (SAGE) recommended in 2017 that should an Ebola disease outbreak occur before the candidate vaccine is licensed, the rVSVΔG-ZEBOV- GP vaccine be promptly deployed under the Expanded Access framework, with informed consent and in compliance with Good Clinical Practice.
• Given the location and access challenges in the area, getting the vaccination teams to the affected area will be challenging but the Ministry of Health, MSF, WHO and partners are working together to address the logistics constraints.
• WHO has a small stockpile of rVSV-ZEBOV. Merck has provided this yet to be licensed vaccines and pledged to allow access to more.

3. Who authorized the use of this vaccine in DRC?

The protocol was reviewed and approved by the national regulatory authorities and the national ethics committee.

4. How will the candidate vaccine be administered and who will receive it?

Ring vaccination, is the recommended delivery strategy. This will be adapted to the social and geographic conditions of the outbreak areas and include people at risk including but not limited to: (i) contacts and contacts of contacts; (ii) local and international health-care and front-line workers in the affected areas and (iii) health-care and front-line workers in areas at risk of expansion of the outbreak. They constitute the “ring” for the vaccination. With their agreement and consent, the individuals in the ring will be considered for the vaccination. After receiving the candidate vaccine, they will be followed up for a set period of time.

5. Is participation in the ring vaccination voluntary?

Yes. Participation in this ‘expanded access’ or compassionate use of the Ebola vaccine is entirely free and voluntary. Each eligible person makes their own decision whether to participate or not and can withdraw at any time. Their rights will be respected. Disregard of whether the eligible person chooses to participate or not, it will not have an impact on their access to health services.

6. What will happen to people who will be included in the ring vaccination?

The team from the Ministry of Health, MSF and WHO will determine who is eligible to be vaccinated, depending on their level of risk and health condition. The following people will be considered for vaccination: (i) contacts and contacts of contacts, (ii) local and international health-care and front-line workers in the affected areas and (iii) health-care and front-line workers in areas at risk of expansion of the outbreak will receive an injection of the candidate vaccine in the arm. As a follow up, they will be visited in their homes to check their health six times – on days 3, 14, 21, 42, 63 and 84 after vaccination.
It is very important that the persons vaccinated continue to protect themselves from Ebola virus infection by not touching a patient's bodily fluids (blood, vomit, saliva, urine, feces), avoid being in direct physical contact with a patient's body (alive or dead), touching the sheets, clothes that may have been contaminated, practice hand hygiene and other preventive measures.

7. Can the vaccine cause side effects?

The vaccine can produce some side effects. People who are vaccinated may have a mild fever or cold like symptoms, malaise that can last 1-3 days. Among those vaccinated, one in five felt temporary swelling at the point of injection into the skin. Some people will have a mild and transient fever 1 to 2 weeks after the injection or some small blisters may appear. It is possible to have joint pain in the feet, hands or knees. Very rarely, vaccines can cause a serious allergic reaction immediately after the vaccine has been administered. This can cause breathing difficulties and weakness.

8. Can a person vaccinated be infected with Ebola by the vaccine?

The vaccine cannot cause the disease because there is no Ebola virus in the vaccine. The vaccine is manufactured according to international standards for vaccines. If a person receiving the vaccine has been infected with the Ebola virus before he/she is vaccinated, they could develop Ebola virus disease after they receive the vaccine. For those infected before the vaccination, the vaccine cannot provide protection. If they develop any symptom of illness, they should immediately contact the vaccination team.