What are Sexually Transmitted Infections?

Human papillomavirus (HPV) is the most common STI worldwide, and also in Spain. Estimates indicate that over 40% of adults in the US are infected with papillomavirus, although in most cases the infection goes undetected and clears spontaneously within a few months. The number of HPV diagnoses has remained stable in recent years.

These infections have also increased in recent years. The infection commonly passes undiagnosed and therefore unregistered which makes data unreliable. It is calculated that between 10% and 20% of the population in the US are infected with type 2 herpes virus (the strain most commonly found affecting the genitals). In Spain, recent studies estimated there are 46.3 cases in every 100,000 inhabitants.

There were 89,239 cases of gonococcal infection diagnosed across Europe in 2017. That represents an overall rate of 22.2 new cases per 100,000 inhabitants. Almost half (47%) of those diagnosed were men who have sex with men. The number of new cases had increased by 30% in all patient groups compared to 2013.

Genital Chlamydia trachomatis is the most common sexually transmitted infection throughout Europe. As many as 409,646 new cases were reported in 2017 at a rate of 146 cases per 100,000 inhabitants. Chlamydia often courses without presenting any symptoms, so it is believed that the number of cases could be much higher. Two thirds (62%) of all cases are reported in people aged under 25 years, most of whom are women.

The incidence of syphilis has been on the increase in Europe since 2010. As many as 33,189 new cases were reported in 2017 at a rate of approximately 7.1 in every 100,000 inhabitants. Six times more men have syphilis than women. The main group affected (almost two thirds of cases, 67%) are men who have sex with men and the majority of cases are diagnosed in people aged over 25 years.

The European Union registered 1.989 new diagnoses of lymphogranuloma venereum in 2017. Four countries (France, the Netherlands, Spain and the United Kingdom) accounted for 86% of the reported cases. Virtually all cases involved men who have sex with men; 64% of patients were also HIV positive. The number of cases reported decreased in 2016. This has been the first reduction in the number of cases since 2009. Spain is one of the countries in which the number of cases has increased compared to previous years.

Hepatitis B is a viral liver infection that can give rise to either an acute problem or a chronic disease. Globally, calculations indicate it affects 5 in every 100 people, but this rate varies according to the country. It is believed that between 2 and 8 in every 100 inhabitants are infected in Spain.

As with hepatitis B, hepatitis C can develop into a chronic disease. There are estimated to be between 130 and 150 million people worldwide with chronic hepatitis C infection. Roughly 1–3 individuals per 100 have been in contact with this disease in Spain. The sexual transmission of this infection has increased in recent years and it mainly affects men who have sex with men.