WHO emergency committee to meet on Zika on February 1

Gleyse Kelly holds her daugther Maria Geovana, who has microcephaly, in Recife, Brazil, January 25, 2016. REUTERS/Ueslei Marcelino

(Reuters) - Companies and scientists are racing to create a Zika vaccine as concern grows over the mosquito-borne virus that has been linked to severe birth defects and is spreading quickly through the Americas.

Zika is now present in 23 countries and territories in the Americas. Brazil, the hardest-hit country, has reported around 3,700 cases of the devastating birth defect called microcephaly that are strongly suspected to be related to Zika.