Scientists took the first step in developing the first vaccine against chlamydia infection, which successfully passed the first phase of testing.
Chlamydia is the most common sexually transmitted disease worldwide, but national diagnostic programs and antibiotic treatments have so far failed to reduce the incidence of infections. Every year, globally, 131 million people are infected, of which almost three quarters show no symptoms. Untreated, this disease can cause infertility.
A team from researchers at the Statens Serum Institute (SSI) in Denmark and Imperial College London (UK) developed a vaccine against chlamydia infection, which was successful in the first phase of testing, the study shows.
The vaccine generated an immune response but did not cause serious adverse reactions.
“The most important result is that we have seen antibodies to protect against chlamydia in the genital tract. Our initial research shows that it prevents chlamydia bacteria from entering the body’s cells. That means we’re pretty close to a chlamydia vaccine,” said one of the study’s authors, Frank Follmann of SSI, quoted by CNN.
This is the first clinical trial for a genital chlamydia vaccine and is the result of 15 years of research.
35 women who were not infected with chlamydia participated in the clinical trial. Of these, 15 received a CTH522 vaccine formula, and another 15 received another vaccine formula. The other five women received a placebo. All vaccinated women received the substance five times (three times they were vaccinated intramuscularly in the arm and twice with a nasal spray).
In both vaccine formulas, participants recorded a 100% immune response that was manifested by antibody production. One of the vaccine formulations, CTH522 combined with CAF01 liposomes (CTH522: CAF01), performed much better, producing 5.6 times more antibodies than the other formula, CTH522 combined with aluminum hydroxide (CTH522: AH), according to Eurekalert. For this reason, scientists have chosen the CTH522: CAF01 vaccine formula for further research. The five women who took placebo did not register new antibodies.
Robin Shattock of Imperial College, who participated in the research, says the next step is to test the vaccine in a clinical trial and until this is done “we won’t know if it really has a protective role or not.”
Diagnostic and treatment tests for chlamydia infection are available, but national treatment programs have had a rather small effect in the fight with the global chlamydia epidemic, the study authors said. According to them, a vaccine could be the most effective way to fight the infection.
One in six women infected with chlamydia develops the pelvic inflammatory disease, which results in chronic pelvic pain, extrauterine pregnancy, and even infertility.
Also, chlamydia infection increases the risk of contracting other sexually transmitted diseases and infections during pregnancy, which can lead to miscarriage, unborn baby’s birth or premature birth.
Sarah Gilbert, a professor of vaccinology at Oxford University who was not involved in the study, said that further research is needed on this vaccine, which shows first and foremost that it is safe for healthy adults. It claims that it is not clear when a chlamydia vaccine will be available on the market, since the costs for each research stage are quite high. While it is scientifically possible for a vaccine to be available in five years, it usually takes 10 to 20 years for one to develop, Sarah Gilbert told CNN.
The World Health Organization (WHO) has said in June that more than one million new cases of sexually transmitted diseases are registered every day. The four major sexually transmitted infections are chlamydia, gonorrhea, trichomoniasis, and syphilis.
Caused by Chlamydia trachomatis bacteria, Chlamydia is a sexually transmitted infection that affects both sexes. However, the most frequent cases are registered among women between the ages of 20 and 25.