The first clinical trials with a vaccine against Chlamydia have been conducted by researchers from Statens Serum Institut (SSI) and Imperial College London and the results were promising. The sexually transmitted disease is one of the largest global health problems so the promising results are very exciting. The trial results were published in the acknowledged scientific journal The Lancet Infectious Diseases.
Frank Follmann, Head of Department at SSI, said:
The vaccine showed the exact immune response we had hoped for and which we have seen in our animal tests. The most important result is that we have seen protective antibodies against Chlamydia in the genital tracts. Our initial trials show them preventing the Chlamydia bacteria from penetrating the cells of the body. This means that we have come a lot closer to a vaccine against Chlamydia.
Each year 131 million people are infected worldwide, but the number is expected to be much higher because most people that have it don’t even know. The infection is easy to treat, but up to 75% have no symptoms. One of the main problems is that people get repeatedly re-infected because since there are no symptoms, people don’t know they have it. If you could introduce a protective vaccine, you could break that cycle.
The First Clinical Trials
There was 15 years of research backing the successful trials. The project to develop an effective Chlamydia vaccine actually began in 2004 and it was in part funded by EU’s 7th framework program and Innovation fund Denmark. Finding the weak point of the Chlamydia bacteria and also finding the most effective way of vaccinating were the two main challenges the researchers faced.
The first challenge of finding Chlamydia’s weak point was solved a few years ago. They found that the weak point was a special protein in the bacteria. From that discovery onwards they spent their time experimenting on finding a new and more effective way of vaccinating to target this exact protein.
In the first clinical trial with this new vaccine, 35 women were vaccinated and all of them developed an immune response against Chlamydia. There were no serious side effects of the vaccine.
Follmann, said:
We took blood samples of the women during the trial. They showed that all vaccinated women had generated specific antibodies and T cells against Chlamydia. Also, as local immunity in the genital tract is important to stop the infection as quickly as possible. During the trial, we collected mucous secretion in a menstrual cup and found high levels of antibodies, including the special mucosal antibody, IgA, which effectively blocks Chlamydia early in the course of infection.
The Real World
The next phase of their research will be to confirm that the vaccine will protect against Chlamydia when women are infected in the real world. Follmann said:
Research shows that the combination of antibodies and T cells does protect against Chlamydia, but, of course, we have to test the vaccine in larger and more long-termed clinical trials to see if it protects against infection. Given the results at hand, we have accelerated our further clinical trials.
A Chlamydia infection typically lasts more than a year and when not treated, it can cause, reduced fertility, infertility, pregnancy outside the uterus, chronic abdominal pain (women), and Epididymitis (men). If the vaccine proves to be effective and safe, it could change millions of lives for the better.
Professor Peter L. Andersen, Head of SSI’s Center for Vaccine Research, said:
The HPV vaccine has shown us how effective vaccination can be against a sexually transmitted infection. We hope to do the same with Chlamydia and, in the long term, combine the two vaccines.
