The Zika virus linked to a microcephaly outbreak in Latin America could spread to Africa and Asia, the continents with the world's highest birth rates, the World Health Organization (WHO) warned as it launched a global response unit against the emergency. Anthony Costello, a WHO expert and paediatrician, added that the disease could have potentially devastating effects for families.

"The problem is that the complications of this relatively mild illness do have potentially devastating effects for families. To have a child with microcephaly and to have a tenfold increase in numbers, and the potential for spread not just across Latin America but into Africa [and] into Asia – which have the highest birth rates in the world – we believe is a matter of public health concern and constitutes an international emergency," Costello said.

Costello also said that the commitment of communities was extremely important as shown during the spread of the Ebola virus last year. "We need mass-community engagement here – mobilisation of women's groups, anti-natal groups and of partners who are going to do a lot to control the vector. So removing stagnant pools of water in urban areas. Looking at upturned flower pots, at rubbish, at tyres. At all the kinds of things that you can do to get rid of breeding sites for the mosquitos and going out and actually killing larvae and mosquitos. Blocking off windows, blocking off doors so that you are not exposed to the biting agent. Now that's not foolproof, but there is an awful lot that you could do to mobilise communities. And if we learned one thing from ebola, mobilising communities is absolutely critical public health measure," Costello told journalists at a news conference in Geneva.

Costello added that one should keep in mind that developing a vaccine against the Zika virus could take years. "I think we have to proceed with the view that the vaccine [is] maybe years not months away. But getting diagnostics is extremely important to look at public health issues here, and generally speaking diagnostics are developed more rapidly than vaccines," Costello said.

French drugmaker Sanofi has launched a project to develop a vaccine against the Zika virus in the most decisive commitment yet by a major vaccine producer to fight the disease. Sanofi said its Sanofi Pasteur vaccines division would use its expertise in developing vaccines for similar viruses such as yellow fever, Japanese encephalitis and, most recently, dengue.