Else Beekman
Sexually transmitted infections are surging in Spain, with official figures confirming an all-time high in new diagnoses. More than 91,000 cases of chlamydia, gonorrhoea and syphilis were recorded in 2024 alone. Twice as much as just three years ago, and ten times higher than a decade earlier.
The numbers were published by the National Epidemiological Surveillance Network (RENAVE). They paint a stark picture: STIs are no longer a fringe concern but they’re a widespread public health issue, especially among young, sexually active adults.
Chlamydia leads the surge with highest rate ever recorded
The most common STI in Spain is chlamydia. If left untreated, this bacterial infection often shows no symptoms but can cause long-term damage. Nearly 42,000 new cases were reported, which is six times more than in 2016, when the infection began to be systematically monitored.
The rise is partly due to improved reporting, as more regional health authorities feed data into the national network. However, the increase also reflects a genuine spike in transmission, especially among young women. The highest incidence was among those aged 20 to 24, with 514 cases per 100,000. Teenage girls (15–19) were not far behind.
Among men, infection rates peaked in the 25–34 and 20–24 age brackets. Despite the numbers, the condition often goes unnoticed,until complications arise.
Gonorrhoea cases explode
Next on the list is gonorrhoea. It’s aggressive, infectious, and making a major comeback. In 2024, 37,257 new diagnoses were confirmed. That is 38 times more than in 2004.
Most cases were in men (83%), with a median age of 32. Women tended to be younger, averaging 27. The highest rates occurred in the 25–34 age group, with over 260 cases per 100,000 residents.
Experts suggest that transmission is higher among men due to a combination of behavioural and biological factors. In particular, men who have sex with men (MSM) represent a large proportion of cases. Among women, same-sex contact is less likely to involve direct mucosal exchange, which reduces the risk of transmission.
Syphilis creeping back
Once nearly eradicated, syphilis is now firmly back on Spain’s health radar. In 2024, 11,930 new cases were reported, which is ten times more than 20 years ago.
Most infections were diagnosed in men (87%), and notably among MSM. The median age was 36. Though the disease often begins with a painless sore, it can later affect the nervous system, heart and other organs if left untreated.
The infection rate stood at 43 per 100,000 men, compared to just 6 per 100,000 women. In about 6% of syphilis cases, individuals were also living with HIV.
Why is this happening now?
According to experts, several factors are fuelling the rise. Increased awareness and testing certainly play a role. But they also point to reduced condom use, particularly among younger generations. Furthermore, changing sexual habits facilitated by dating apps are of influence.
Another issue: many infections show no symptoms at all, making early detection a challenge. People may unwittingly spread an STI without realising they’ve contracted one.
A call for stronger prevention measures
The steady rise in chlamydia, gonorrhoea and syphilis has triggered calls for enhanced sexual health education, easier access to testing, and renewed emphasis on condom use.
Public health campaigns are particularly needed among the under-35s—the group most affected by these infections. Without targeted prevention, experts warn that the upward trend will likely continue into 2025 and beyond.