UK Researchers: The immune response from three Ebola vaccines, including VSV-EBOV, lasts at least 2.5 years.
November 1st, 2018Durability of immune responses induced by three leading candidate Ebola vaccine regimes; rVSV ZEBOV, ChAd3 EBO Z-MVA BN-Filo and AdHu26.ZEBOV-MVA BN Filo
| October 29, 2018, 4:30 PM – 4:45 PM | Sheraton – Grand Ballroom A/B (5th Floor) |
- Authors
- Katie J. Ewer1, Catherine Smith2, Esha Sarkar2, Georgina Bowyer1, Thomas Rampling1, Catherine Mair1, Duncan Bellamy1, Suleman Sabir3, Christopher Davies3, Navin Venkatraman1, Rebecca Conway-Jones1, Danielle Campbell2, Charlotte Boyer2, Adrian V. Hill1, Emma Thomson3, Matthew D. Snape2
1The Jenner Institute, University of Oxford, Oxford, United Kingdom, 2Oxford Vaccine Group, University of Oxford, Oxford, United Kingdom, 3MRC-University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
“Of the vaccines developed in response to the 2014-16 Ebola outbreak in West Africa, three which encoded the Zaire Ebola glycoprotein, showed acceptable reactogenicity and promising immunogenicity in early-stage clinical trials – a single-dose approach based on a replicating vesicular-stomatitis virus (rVSV ZEBOV) and two heterologous prime-boost combinations using replication-deficient adenoviruses (ChAd3 and AdHu26) to prime and the multivalent MVA BN-Filo to boost. The rVSV ZEBOV vaccine showed 100% vaccine efficacy in a phase III ring vaccination trial in the short-term following exposure to Ebola virus disease (EVD) cases. However, durability of protective efficacy has not been assessed. Clinical trials were undertaken in Oxford of both prime-boost regimes and volunteers have been followed up to determine durability of both humoral and cellular immunity. This revealed that 91% of 43 recipients of AdHu26/MVA vector vaccine recipients had positive glycoprotein specific IgG titres at 2.5 years post immunisation, as did 54% of 13 recipients of Chad3/MVA vectored vaccines. Furthermore, in October 2015, rVSV ZEBOV was administered to 26 contacts of a UK health-care worker who had become infected with EVD in Sierra Leone, recovered and then subsequently relapsed. Using samples from this cohort, we will be able to undertake for the first time comparative immunogenicity measurements using a standardised ELISA and validated ELISPOT assay to determine humoral and cellular immunity against the Zaire ebolavirus glycoprotein induced by these three vaccine regimes. Samples taken 2.5 years post-vaccination will be compared to determine whether differences in quality, quantity and persistence of immunity are observed. These data are important for long-term strategic planning for prophylactic protection of front-line healthcare workers in regions at risk of future outbreaks.