Persistence of the immune response after Ebola vaccine immunisation
Research type
Research Study
Full title
Evaluating the long term immunogenicity of Ebola Virus Vaccines Ad26-ZEBOV and MVA-BN-Filo
IRAS ID
219153
Contact name
Matthew Snape
Contact email
Sponsor organisation
University of Oxford
Duration of Study in the UK
0 years, 6 months, 15 days
Research summary
Summary of Research
The Ebola Virus Disease (EVD) outbreak in West Africa in 2014 was followed by a major boost for vaccine development. A number of Ebola virus vaccines developed on various platforms are at different stages of clinical study. Four of these vaccines had their first human in trial at Oxford. The Phase 1 trial with two vaccines called Ad26-ZEBOV and MVA-BN-Filo used in combination have shown to be effective in eliciting an immune response to the virus. These vaccines have been shown to produce, antibodies and white blood cells against a surface protein on the Ebola virus. Our studies to date have shown that the immune responses to the vaccines are sustained for twelve months after the administration of the primary vaccine. It is important to determine the duration of the persistence of this immune response to establish the clinical use of the vaccines and whether or not booster dose will be required in susceptible population. We propose to undertake this follow-on study on participants of the Phase 1 trial to investigate the persistence of the immune response over an extended period. We will test the participants for Ebola glycoprotein (GP) specific antibody and white blood cell response in their blood. All participants from the Phase 1 study who had received the two Ebola virus vaccines mentioned before will be invited to take part in the study. Following consenting and enrolment in the study, all participants will will undergo a blood test.
Summary of Results
In this study we directly compared the durability of the antibody and T-cell responses induced by a prime-boost regimen of Ebola vaccines Ad26.ZEBOV followed by MVA BN-Filo (and vice – versa) with different time periods between doses, and by a single-dose prime regimen of r-VSV-ZEBOV.
We were able to show that there was no significant difference in magnitude of antibody titre induced by the three vaccine regimes: approximately 75% of recipients of MVA BN Filo / Ad26.ZEBOV or rVSV remained seropositive at least 2 years post-vaccination. There was no loss of persistence between 2 and 3 years with MVA BN Filo / Ad26.ZEBOV: this is likely to achieve target product profile criteria of 2-year protection described in CIDRAP/WHO TPP (Ebola Virus Disease (EVD) Vaccine Target Product Profile) report, 2014.
The study results also showed that the frequency of T cells specific to Ebola glycoprotein were significantly higher after the two-dose regimens than with single dose vaccines in these cohorts, and this applied regardless of which order the Ad26.ZEBOV and MVA BN-Filo vaccines were given. Testing against the Sudan Ebolavirus (as opposed to the Zaire Ebolavirus) revealed that antibodies induced by AD26.ZEBOV/MVA-Bn-Filo were cross reactive against this strain; this was not the case with the rVSV vaccine.
In summary, these viral vector prime-boost regimes, can be flexibly deployed and induce potent cellular and humoral immune responses that persist for 3-5 years post-prime. These data are crucial for understanding the potential duration of protection provided by these vaccines for populations at ongoing risk of exposure, for example those living in endemic areas or rapid-response health care workers.
REC name
South Central - Oxford A Research Ethics Committee
REC reference
17/SC/0169
Date of REC Opinion
25 Apr 2017
REC opinion
Favourable Opinion