In a commentary on the Uganda trial findings that appears in the same Lancet issue, Saranya Sridhar, MBBS, DPhil, with the Jenner Institute at the University of Oxford in the United Kingdom, wrote that West Africa's Ebola epidemic is a sobering reminder of the devastating effects of filovirus outbreaks.
He said a crucial question, as with other vaccines, is whether they are as safe and immunogenic when used in Africa as elsewhere. The Ugandan trial sheds some light on the issue, he said, yielding results similar to those of an American trial of the same vaccines and providing a glimpse of what might be expected from ongoing trials of virus-vectored Ebola vaccines in Africa.
However, Sridhar urged cautious interpretation of the results, given the small number of people in the Ugandan trial and results from tuberculosis vaccine trials that showed lower vaccine immunogenicity in African populations. He also said the low proportion of Ugandan participants who showed an immune response to the Ebola vaccine alone or combined with the Marburg virus vaccine raises the question of whether a low response to the ChAd3would affect vaccination strategies for use in West Africa's outbreak. "Will it be necessary to give higher doses, multiple doses, or a modified vaccinia Ankara booster?" he wrote.
Sridhar said that in light of the Ebola epidemic, researchers and policymakers should ask themselves if a filovirus vaccine should have been further along in development. He added that the response shows how quickly vaccine developments can progress: "This study is the first step on the aspirational road towards the deployment of filovirus vaccines in Africa and must serve to shake the metaphorical cobwebs that can stall our advance towards this destination.