A vaccine candidate developed for preventing chlamydia, an STI, has shown promising results in animal studies and may prove highly beneficial specifically for women if approved for human use.

Researchers at Canada's McMaster University developed a nasal vaccine containing proteins of chlamydia's infection and replication system to prime the body for immune response. The bacterium is known to use protein appendages known as Type III Secretion System to infection host cells and replicate. By priming mice with a novel antigen called BD584 containing these proteins, researchers were able to elicit an immune response that prevented infection.

Chlamydia infection may be asymptomatic or the symptoms may go unnoticed. If left untreated, the bacteria may cause upper genital tract infections, pelvic pain, infertility in women and blindness.

"Vaccination would be the best way to way to prevent a chlamydia infection, and this study has identified important new antigens which could be used as part of a vaccine to prevent or eliminate the damaging reproductive consequences of untreated infections," said David Bulir, co-author of study published in journal Vaccine.

Chlamydia affects over 100 million people worldwide and is recognized as the biggest cause of preventable blindness. The vaccine candidate  not just prevented an infection in mice; it also reduced shedding of bacteria from vagina by as much as 95 percent and prevented hydrosalpinx, a symptom of chlamydia infection evinced by blocked fallopian tubes.

"Vaccine development efforts in the past three decades have been unproductive and there is no vaccine approved for use in humans,"Bulir said.

A vaccine against Chlamydia could prove crucial for the vulnerable mainly individuals who have sex with multiple partners. Given that chlamydia is known to exhibit resistance to commonly antibiotics including doxycycline, azithromycin, and ofloxacin, a vaccine may be the only hope against it.