The World Health Organization (WHO) talk about of 330 million cases a year. The highest transmission is detected especially in underdeveloped countries, where these diseases are mostly related to poor sanitation and socio-economic conditions.
Unfortunately WHO statistics on the transmission of sexually transmitted diseases show how well 111 million new cases occur among young people aged under 25 years. This is because adolescents are the population group that makes less use of condoms.
The World Health Organization estimates that the most common STDs are vaginitis Trichomonas vaginalis and infection with Chlamydia trachomatis, with respectively 250 million and 100 million cases each year.