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Scientists have intentionally infected people with the Zika virus to test vaccines and found that infected participants had mild symptoms and did not become pregnant. This raises hopes for testing vaccines in controlled settings during low Zika incidence. This development was presented at a medical conference.
Scientists gave doses of Zika virus (red; artificially coloured) to healthy volunteers in the hope that a similar protocol could be used to trial vaccines.Credit: Dennis Kunkel Microscopy/Science Photo Library
For the first time, scientists have deliberately infected people with Zika virus to learn whether such a strategy could help to test vaccines against the pathogen.
The virus can cause severe birth abnormalities in babies born to parents infected during pregnancy. It also has been associated with neurological problems in adults, although those cases are rare. But infected study participants had only mild symptoms, and none became pregnant during or immediately after the trial. The results raise hopes that ‘human challenge’ programmes — in which volunteers are exposed to a pathogen in a controlled setting — could make it feasible to test vaccines at a time when Zika incidence is low.
“This is a great scientific gain in terms of the development of a vaccine,” said Rafael Franca, an immunologist at the Oswaldo Cruz Foundation in Ribeirão Preto, Brazil. The results are scheduled to be presented today at the annual meeting of the American Society of Tropical Medicine and Hygiene in Chicago, Illinois.
Zika’s rise and fall
A surge of neurological congenital problems associated with Zika, which is spread by mosquitoes, led the World Health Organization (WHO) to declare a public-health emergency of international concern