“We think that the Zika virus will be around for three to four years and it will probably disappear and then reappear in people being born after that, who will be susceptible again. So there's an urgency to have a vaccine for women, who may get pregnant during this four-year time. We have to be very quick,” says Jorge Kalil, head of Brazil’s Butantan Institute and president of the International Union of Immunological Societies.
“We are working on an inactivated vaccine in which you produce the virus, kill the virus and use the entire killed virus to obtain the antibodies that will neutralise the live virus. The advantage of such a vaccine is it doesn’t have many problems but I think this kind of vaccine will take a long time. In my opinion, it should be used for youngsters who might be threatened by the second wave of Zika in 10 to 15 years,” Kalil tells SciDev.Net.
“We are working on an inactivated vaccine in which you produce the virus, kill the virus and use the entire killed virus to obtain the antibodies that will neutralise the live virus.”
Jorge Kalil, Butantan Institute
He adds that during the southern hemisphere winter, the mosquitoes have disappeared in Brazil (the epicentre of the virus) and “in week 25 as of 8 June, we didn’t report a single case, but the virus may reappear in our summer season in November-December”.
Butantan Institute is Brazil's largest producer of immunobiological products. It has worked for nearly a decade with the US National Institutes of Health on a vaccine for dengue and believes it can piggy-back on that research to reach a solution for the Zika virus. The institute is cultivating the virus in quantities sufficient to start tests in isolating antibodies in rodents. Researchers will then attempt to produce them in larger quantities in horses, purifying the antibodies in the laboratory before starting tests on humans.
Giovanna Barba-Spaeth, in collaboration with Imperial College London (United Kingdom) and the University of Vienna (Austria), has identified antibodies able to efficiently neutralise both the dengue virus and the Zika virus. The description of the binding site for these antibodies identical for both viruses could lead to the development of a universal vaccine offering simultaneous protection against both dengue and Zika diseases.
Cameron Simmons from the Peter Doherty Institute for Infection and Immunity in Melbourne spoke of how Zika has highlighted the absence of good tools to fight viral infections transmitted by Aedes aegypti mosquitoes. He is involved in a large programme using Wolbachia bacteria. “Wolbachia makes the Aedes aegypti mosquito resistant to virus — Zika, dengue and chikungunya. Essentially, it makes the main vector of these viruses non-permissive for infection with those viruses. We are soon going to begin gold standard cluster randomised controlled trials in Vietnam and Indonesia to establish the efficacy of the Wolbachia technology to stop transmission of these viruses,” Simmons says.
Meantime, he notes, “Global public health will require old-fashioned tools such as vector control and advising personal protection as mainstays of healthcare until we have first generation vaccines, hopefully in the next two years.”
This piece was produced by SciDev.Net’s South-East Asia & Pacific desk.