Two Zika vaccine candidates discovered

Back in February the World Health Organisation declared the zika virus epidemic in Brazil to be a public health emergency of international concern. At the top of the list was the link between Zika infection and babies being born with microcephaly or an abnormally small head. Now scientists in the US have taken the first steps towards developing a much-needed vaccine, which they've so far tested successfully on mice. Dan Barouch from Harvard University spoke to Chris Smith...