Facts & FAQ

Short facts

Chlamydia trachomatis

  • The TracVac project develops a vaccine against bacterium Chlamydia trachomatis
  • The root cause of trachoma is C. trachomatis infection in the human eye.
  • The bacterium lives inside the human cells, impeding the immune defense of the infected person.
  • Ct serovars A, B, Ba and C infect the human eyes.
  • Genital chlamydia infection is caused by a different subgroup (serovar) within the C. trachomatis species.
  • Animals in nature (e.g. cattle, birds and koalas) can be infected by other Chlamydia species (e.g. C.psittaci, C. muridarum, C. pecorum)

Trachoma

  • Trachoma is behind the blindness or visual impairment of currently 1.9 million people.
  • The disease is associated with poverty, crowded living and inferior sanitary arrangement.
  • Visual impairment resulting from trachoma typically starts at age 30-40.
  • In highly endemic areas, visual impairment can occur already in childhood.
  • 182 million people live in endemic districts globally (April 2017).
  • Trichiasis, a potentially blinding sequela of frequent Ct infection, requires surgery.
  • In 2016, 247 000 people received surgery because of trachoma.
  • In 2016, 86 million people received antibiotics to treat trachoma.

A public health problem

  • Trachoma is currently defined as a public health problem in 42 countries, whereof 27 in the Africa.
  • More women than men are blinded by trachoma.
  • In endemic areas where individuals are re-infected at high frequency, the effectiveness of antibiotics is limited.

Efforts to eliminate

  • In 1996, WHO launched an alliance for global elimination of trachoma, GET2020.
  • World Health Assembly adopted resolutions WHA66.12 on neglected tropical diseases and  WHA51.11 aims to eliminate trachoma globally. WHO adopts the SAFE elimination strategy:
    • Surgery for advanced disease
    • Antibiotics to clear C. trachomatis infection.
    • Facial cleanliness
    • Environmental improvement to reduce transmission
  • Numerous non-governmental organisations (NGOs) globally support implementation strategies to achieve the GET2020 goals.
  • Trachoma is associated with poverty, crowded living and inferior sanitary arrangement. Therefore projects supporting environmental infrastructures, like eg. accessibility to clean water and sanitation, crucially influence disease spreading.
  • EU supports the GET2020 in the Horizon2020 research and innovation program, and has also funded e.g. well drilling in areas short of clean water.

FAQs

Could a trachoma vaccine protect against genital Chlamydia?
Trachoma and genital Chlamydia trachomatis infections are caused by separate serovars (subgroups, within the C.trachomatis species).  A vaccine against trachoma would therefore not guarantee immunity against genital chlamydia, or vice versa, although some degree of immunity against genital chlamydia could be conferred by a genital C. trachomatis vaccine.

When is a country declared trachoma free?
WHO defines elimination of trachoma by dual criteria: (1) prevalence < 0.2% in adults > 15 years and (2) <5% trachomatous inflammation follicular in children 1-9 years.

How many people have trachoma in the westernized world?
The disease was endemic in Europe and North America only a century ago, but is now gone due to improved living conditions. In Australia, trachoma is still a public health problem in some aboriginal communities. Today, the disease spreads particularly well in dry and poor regions due to inadequate clean water supply.

Why is antibiotics not sufficient in the endemic trachoma areas?
Antibiotics eliminate ongoing infections but leave no protection against reinfection. As people in endemic areas area are frequently exposed and reinfected by C. trachomatis, the effect of antibiotics is short-lived.

Who is blinded by trachoma?
Typically a 30-40 year old person living in a poor, rural and dry area. But children can also be blinded in endemic areas. Africa holds most endemic countries.

Last revised 21 September 2017