Chlamydia sex infection vaccine passes safety test in shot in arm for treatment

A vaccine to protect against Britain’s most common sexually transmitted infection chlamydia is safe and has shown promising signs of being effective, a clinical trial has found.

Researchers found the vaccine provoked an immune response during preliminary tests on 35 healthy women.

Further trials will now be carried out to determine whether it can fully protect against the infection, but experts say it is an “important first step” in tackling the condition.

Professor Robin Shattock, fromtheimperialcollegelondon, said: “The findings are encouraging as they show the vaccine is safe and produces the type of immune response that could potentially protect against chlamydia.

“The next step is to take the vaccine forward to further trials, but until that’s done we won’t know whether it is truly protective or not.”

Chlamydia is the most common bacterial STI in the world.

The infection accounts for almost half of all STIS diagnosed in England, with young adults the most affected.

There were 16,338 diagnoses of chlamydia in Scotland last year, up from 15,685 in 2017.

Chlamydia can lead to infertility, as well as complications such as ectopic pregnancy, arthritis and increased susceptibility to other STIS including HIV.

The infection is treated with antibiotics, but people can still catch it again. As many as three out of four cases show no symptoms.

Prof Shattock said: “The major issue with chlamydia is the long-term consequences.

“It is very treatable if identified, but as many people don’t have symptoms it can be missed and the biggest problem is that it can go on to cause infertility in women.

“One of the problems we see with current efforts to treat chlamydia is that despite a very big screening, testing and treatmentprogramme,people get repeatedly re-infected. If you could introduce a protective vaccine, you could break that cycle.”

The study, led by Imperial College London and the Statens Serum Institut in Copenhagen, tested two different formulations of the vaccine to examine which would perform better.

Both formulations provoked an immune response in 100 per cent of participants – compared with no immune response in those given a placebo – but one was found to perform better and produce more antibodies.

The experts hope this formulation will undergo further clinical development.

The research found the vaccines produced no serious adverse reactions.