(Reuters) - A vaccine to prevent infections caused by the deadly mosquito-borne Zika virus induced immune response and was found to be safe in an early stage trial, Emergent BioSolutions Inc and partner Valneva SE said on Monday.

The vaccine, VLA1601, which was tested in two doses in 67 adult patients, induced the body to produce neutralizing antibodies against the virus, the companies said.

First discovered in 1947, the Zika virus reached epidemic proportions in Brazil in 2015, when thousands of babies were born with birth defects.

However, bringing a vaccine to market has proved difficult, with drug companies including Japan’s Takeda Pharmaceutical and Inovio Pharmaceuticals Inc in the race.

Emergent announced an exclusive worldwide license deal for Valneva’s Zika vaccine technology in July last year.

Monday’s release contained analyses up to day 56 after the first vaccination, with final analysis - at day 208 - expected in the first quarter 2019, the companies said.