A vaccine to protect people against a common sexually transmitted infection, chlamydia, has passed the initial safety tests.
The first of its kind to enter human trials, the vaccine has proven to be safe and can protect people from getting the bacteria that accounts for nearly half of all sexually transmitted infections.
In the study published Thursday in The Lancet Infectious Diseases, researchers compared two different formulations of the vaccine alongside a placebo jab in 35 women who were not infected with chlamydia. Every single woman who got the vaccine showed an immune response but none of the women who got the placebo exhibited such a response.
Both formulations appeared to be safe, but one stood out as a front-runner. The researchers now want to move this vaccine into the next phase of testing.
The trial, conducted by researchers from the Imperial College London, revealed that the experimental vaccine is promising because it targets the bacterial infection where it hides — inside the cells.
"Chlamydia is an expert in hiding. People go around with chlamydia infections without knowing it and spread it to other partners. It is only discovered through screening when a young woman goes to a doctor for birth control or other treatment,” said Dr Frank Follmann, director of the department of infectious disease immunology at Statens Serum Institut in Denmark.
"We hope this will be the first of many trials, so we can measure efficacy in the real world," he said. Chlamydia is a bacterial infection that resides in semen and vaginal fluid. It is passed on through unprotected sex (even if there is no penetration).
Often, the infected person will have no symptoms, which is why people sometimes refer to it as a "silent" disease. If it is not treated with antibiotics, it can cause serious complications and affect fertility. People under 25 who are sexually active are advised to get tested for chlamydia every year since it particularly affects men and women under the age of 25.
Although antibiotics can treat chlamydia, people can catch the infection again if they come into contact with it.
Chlamydia remains the most common STI despite screening and effective treatment being available.
If untreated, the illnesses can lead to serious and chronic health effects that include neurological and cardiovascular disease, infertility, ectopic pregnancies, stillbirths and increased risk of HIV.