A Science research article published yesterday (Aug. 4) shows that scientists may be on the right path to beat the Zika virus. The study used three different vaccines to successfully immunize monkeys. This “brings us one step closer to a safe and effective Zika vaccine,” said researcher Dr. Dan Barouch to the Associated Press.

Researchers will begin testing one of the vaccines on humans this year. The National Institute of Health, on the other hand, began its vaccine’s human trials this week. The study includes at least 80 “healthy volunteers” between the ages of 18 and 35. Inovio Pharmaceuticals, a private biopharmaceutical company, administered its vaccine to its first subject last week.

To date, 1,825 people in the continental U.S. are afflicted with the virus, according to the CDC. The number triples when U.S. territories are taken into account. This week, the CDC issued its first U.S. travel warning for Florida, where local mosquitoes are now transmitting the virus that can lead to brain deformities in newborns. 

Zika is spreading, in large part, due to climate change, which has improved environments for the Aedes aegypti mosquito that carries the virus.