It was just a few months ago that the Zika virus was declared a global health threat, but already there are five potential vaccines close to being tested. Recent technical and scientific innovations have accelerated the ability to fight emerging infectious diseases as they develop.
One of the latest signs of progress came in April 2016 when the World Health Organisation recommended that countries consider using Sanofi’s vaccine to combat dengue fever. Products are now in development to fight other more obscure diseases, for which the prospects of a treatment or a vaccine have so far seemed scant, from the Marburg and West Nile viruses to Ebola.
“These are very exciting times,” says Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases. “We have made big advances with vaccines.”
Dr Fauci gives the example of a DNA platform enabling researchers to create genes from a range of microbes and develop prototype vaccines for diseases quickly. The US Department of Defence is one of several sponsors that has provided funding for this as it tries to tackle the threat of bioterrorism.
That funding has allowed researchers to prepare for naturally occurring lethal threats as well as bio-warfare. Mr Fauci says that, with support from the US National Institutes of Health, one experimental Zika vaccine will begin tests by September for both safety and its ability to generate an immune response in healthy volunteers.
“If it looks safe, with a reasonably good immune response, we’ll prepare for mid-stage trials in 2017,” he says. “It could prove efficacy within a year or so. And a couple of other candidate vaccines are not too far behind.”
Innovation is not only taking place in the development of new vaccines, however. Without a more efficient system of delivery and administration new vaccines are useless, especially in remote parts of poor countries, where the burden is greatest. Inadequate infrastructure, hot climates and lack of access to refrigeration risk spoiling a vaccine’s fragile contents.
These are very exciting times. We have made big advances with vaccines for which our body makes a good immune response
Among the efforts to make delivery easier is one by Etisalat, the United Arab Emirates-based telecoms operator, which has launched a programme to deliver vaccines by drone. Flying cool boxes can travel to remote areas across Africa and Asia, recharging their batteries at mobile telephone base stations.
New technology is also being employed in vaccine delivery in Pakistan. To address suspicions that doses of dengue were being intercepted by corrupt local officials before they could reach their targets, Punjab state has developed a system linking its staff by GPS. An app allows health workers to geo-tag sightings of the dengue-bearing mosquito, and also to send digitally stamped pictures of themselves carrying out fieldwork with a time and a GPS location.
But not all diseases can be tackled rapidly. There are some microbes, viruses and parasites for which the body does not naturally build an effective immunity, including, most notably, the HIV virus. “For [these] we have to go through a lot of kinds of tricks,” Dr Fauci says.
Mark Feinberg, head of the International AIDS Vaccine Initiative, a public-private partnership, acknowledges the size of the challenge of fighting HIV. “I don’t think you’d be working in the field unless you were an optimist. I remain an optimist, but this is perhaps the most complicated scientific challenge in vaccine development,” he says.
Johan Van Hoof, head of infectious diseases and vaccines at Janssen, part of the Johnson & Johnson pharmaceuticals group, says he also has cause for optimism. “For HIV, we have extremely promising data in very stringent monkey models,” he says. “We think we have a breakthrough approach in the clinic, and we hope to start testing it in South Africa by the end of 2017.”