UPDATE 3-Zika virus set to spread across Americas, spurring vaccine hunt
* Mosquito-borne virus linked to birth defects in Brazil
* Brazil's Butantan Institute aims to develop vaccine
* GSK and Sanofi reviewing vaccine possibilities
* More research needed into potential sexual transmission (Adds comment from GlaxoSmithKline and Sanofi, graphic link)
By Tom Miles and Ben Hirschler
GENEVA/LONDON, Jan 25 (Reuters) - The mosquito-borne Zika virus, which has been linked to brain damage in thousands of babies in Brazil, is likely to spread to all countries in the Americas except for Canada and Chile, the World Health Organization said on Monday.
Zika transmission has not yet been reported in the continental United States, although a woman who fell ill with the virus in Brazil later gave birth to a brain-damaged baby in Hawaii.
Brazil's Health Ministry said in November that Zika was linked to a foetal deformation known as microcephaly, in which infants are born with smaller-than-usual brains.
Brazil has reported 3,893 suspected cases of microcephaly, the WHO said last Friday, over 30 times more than in any year since 2010 and equivalent to 1-2 percent of all newborns in the state of Pernambuco, one of the worst-hit areas. Continued...