It is Danish and English researchers who have completed a phase one study, that is, a study on healthy people, which the Swedish National Broadcasting Service first reported. Björn Herrmann, associate professor of clinical microbiology, researches chlamydia at Uppsala Academic Hospital and says the study is important as it is the first phase one study of a vaccine for chlamydia.

- In this way, it's a breakthrough, he tells SVT News.

He points out that there are still many years left until there could be a vaccine on the market, but the study of this vaccine candidate has shown two things:

- Partly that it has not shown any harmful side effects, it is important when moving on. The other important thing is that the immune system has started in a way that one can expect protection against chlamydia infection, says Björn Herrmann.

130 million are infected every year

Chlamydia is the most common sexually transmitted disease in the world. Each year, around 130 million people worldwide are infected, according to the World Health Organization, and 30,000-35,000 of them are Swedes.

Chlamydia can be treated with antibiotics, but the infection does not always cause symptoms, making it difficult to stop the spread of infection. The infection can lead to serious complications, especially for women who may be suffering from fallopian tubes, ectopic pregnancy and infertility.

- These are important reasons for vaccinating, says Björn Herrmann.