Chlamydia, the most common sexually transmitted infection, has proven safe in tests, a BBC news site reported.
This is the first such vaccine to be released for clinical testing, researchers wrote in The Lancet Infectious Diseases.
Chlamydia bacteria spread through unprotected sex. The infected person often has no or very mild symptoms and is therefore called a silent disease. It can be cured with an antibiotic, but if left untreated, it can lead to serious complications and endanger fertility. Vaccination is needed because, although the disease is treatable, it can be caught again.
The vaccine is expected to provide long-term protection.
During the tests, researchers at Imperial College London tested two versions of the vaccine and one placebo injection of the active ingredient in 35 women.
Both versions proved safe, but one was more promising, with researchers looking to test the latter in the next phase of the study.
“The results are promising as they have shown that the vaccine is safe and elicits an immune response that can protect against chlamydia. The following tests will have to prove whether or not it really protects. We hope to start next year or two the next series of tests, and if it goes well, we will have the vaccine in about five years, “explained Robin Shattock, research director.