The Keystone Symposia organisation held a meeting entitled “New Approaches to Vaccines for Human and Veterinary Tropical Diseases” in Cape Town this week (May 22-26, 2016). A summary of the meeting was given as:
“Human and livestock vaccines can contribute to improved human welfare and income generation by maintaining human health and meeting the demand for meat, milk and fish in developing countries. All of these factors contribute to the growing importance of improving food safety, availability and nutritional security. An important component of this Keystone Symposia meeting will be to stimulate crosstalk between the human and veterinary vaccine communities by highlighting cross-cutting technical advances and new science and knowledge from laboratory and field research. The meeting will also provide a rare opportunity for scientists from the Northern and Southern hemispheres to interact and pool resources and knowledge in the common fight against tropical diseases.”
It succeeded admirably in a couple of these goals: there were delegates there from 31 African countries, as well as many Europeans, Brits and Americans; the juxtaposition of veterinary and medical talks on similar themes created an excited buzz among folk who hadn’t been exposed to the “other”; there was a wealth of dazzling new tech on display in talks, and intriguing insights into how similar – and sometimes, how different – human and animal responses to vaccines were. It was obvious that approaches used to develop malaria vaccines could benefit animal vaccinology, and indeed, Vish Nene and colleagues from ILRI in Kenya are following some of the same approaches in their work with the East Coast fever disease organism in cattle.
But, there were a couple of buts. An important one for me was that while there were many Africans there, they were not much exposed in talks, apart from several South Africans. While amazing results were displayed from deep sequencing of antibody gene repertoires of humans and animals and how these developed with affinity maturation; while grand predictions were made as to how bioinformatics and molecular design would revolutionise vaccinology – this was more of the same kind of thing we have got used to in HIV vaccine meetings over nearly twenty years, where Big Science is always going to provide a solution, but never quite gets to it. Why was there no mention of antibody therapy for Ebola, when this (OK, I’m biased) was the single most exciting thing to come out of the Ebola outbreak and the international response to it?
I hate to be cynical, but seriously: is there one single vaccine in advanced human trial right now that is a result of intelligent molecular design? Has ANYTHING that has been designed from crystallographic evidence or from cryoEM data actually proven useful in animals? Has dissection of the anti-HIV antibody response development actually, really, taught us anything useful about how we should develop vaccines?
I told you I was cynical – and my cynicism was reinforced by a couple of displays of “My Ebola vaccine is better than YOUR Ebola vaccine!”, by folk who shall remain nameless. Mind you, the tale of how Ebola vaccines were deployed so rapidly, and how what could have been a 15+ year saga was compressed to less than a year for the rVSV-ZEBOV and ChAdOx vaccines. was truly inspirational. It is indeed an object lesson in how to respond to an emerging disease that big companies and philanthropic organisations were able to make many thousand doses of different vaccine candidates in just a few months, and that these could be deployed in human “trials” – actually, genuine deployment in ring vaccination for the VSV candidate – almost immediately. Adrian Hill of Oxford asked the question, albeit outside the meeting at a seminar: if this was possible for an Ebola outbreak, why isn’t it possible for everything else too? Why can’t we do it for Zika virus, and for MERS-CoV too?
If there is a Big Lesson to come out of this meeting, why can’t it be – Let’s Make Vaccines Faster!
Oh, there were big plusses too. There were fascinating parallels to be drawn in the approaches to developing vaccines for malaria and TB and animal parasitic infections; some of the fancier techniques discussed for human vaccines could obviously find applications in veterinary vaccinology; there were even suggestions for vaccine candidates for animals that were drawn from homologous genes in human and animal apicomplexans (=malaria organisms).
And yet, and yet: I felt that the final address, by Chris Wilson of the Bill & Melinda Gates Foundation, on: “Cross-Disciplinary Science to Accelerate the Discovery of Vaccines for Global, Zoonotic and Emerging Infectious Diseases” exemplified some of the problems inherent in trying to marry up developed and developing world science, especially in vaccinology. Part of teh talk was great: he gave the best description I’ve yet heard of why it could be feasible to inoculate Aedes spp. with Wolbachia, and why it could significantly impact transmission of flavi- and other viruses. His description of gene drive technology for wiping out selected mosquito populations was also succinct, and masterly – and appropriate for a developing world audience. Then he got on to how dissection of antibody maturation pathways and flavivirus E protein design could provide paths to good vaccines, and the cynicism kicked in again.
We don’t need either technology to get to vaccines for HIV or for flaviviruses that we can test in the near future, and which could have very significant impacts on millions of people.
Really: we don’t. Extant HIV vaccine candidates are almost certainly better than the RV144 Thai trial vaccine components, and they had an efficacy of 60% in the first year. We already have YFV and dengue and JEV live vaccines – why don’t we use one or several of them in combination with an engineered YFV vaccine to protect against ALL epidemic flaviviruses? Given the Ebola example, we could deploy vaccines for HIV and for flaviviruses in a year or less, and they would have an impact that would tide us over while fancier products were being made. Seriously: we are always waiting for the next best thing; let’s just apply what we know and what we have NOW to make an impact – instead of, like theoretical physicists, perpetually considering the problem of the spherical horse instead of just going out and riding one.
And that should have been one of the Big Lessons, and we missed it.