The number of sexually transmitted infections (STIs) is rising sharply across Europe, prompting concern among health experts as cases of gonorrhea and syphilis reach levels well above those recorded a decade ago.
The resurgence follows a period in which STI rates temporarily declined during the COVID-19 pandemic. Since 2021, however, infections have increased rapidly, with health authorities warning that the trend reflects a genuine rise in transmission rather than simply more widespread testing.
Gonorrhea and syphilis cases surge
As reported in the Economist, in May, the European Centre for Disease Prevention and Control (ECDC) reported that Europe recorded 100,000 cases of gonorrhea in 2024, more than three times the number reported in 2015.
Syphilis cases more than doubled over the same period, reaching 46,000 in 2024.
Chlamydia, the most common STI, was the only major infection to return to its 2015 level after reaching a peak in 2022.
The ECDC concluded that the increase cannot be explained solely by greater access to testing.
“There is a real increase in transmission,” Dr. Stella Bivol, head of the World Health Organization’s European office for sexually transmitted infections, told The Economist.
The sharp rise immediately after the pandemic may partly reflect the reopening of medical testing services following lockdowns. However, that explanation does not account for the continued increase in cases after restrictions were lifted.
Declining condom use raises concerns
Some experts have linked the rise in infections to changes in sexual behavior and the greater use of dating apps, which can facilitate changes in sexual partners. However, evidence supporting that explanation remains limited.
A more convincing explanation may be the decline in condom use.
A WHO study involving 250,000 15-year-olds across Europe between 2014 and 2022 recorded a significant decline in condom use. However, the study covered only one age group, while there is limited data on changes in condom use among people aged 20 and older, who account for most STI infections.
Regardless of the precise causes, experts agree that the increase presents a serious health risk.
STIs are generally treatable, but they can have serious consequences if they are not diagnosed promptly. Chlamydia and gonorrhea can cause testicular infections in men and infertility in women. Syphilis can be fatal.
Congenital syphilis doubles
One of the most concerning developments is the rise in congenital syphilis, which is transmitted from mothers to their babies.
Although rare, congenital syphilis can be fatal. The number of reported cases doubled between 2023 and 2024, reaching 140. Most were recorded in Bulgaria, Portugal and Hungary.
The increase has been recorded across Europe.
Between 2023 and 2024, gonorrhea cases increased in Bulgaria, France and Italy. Belgium and Hungary saw sharp increases in syphilis cases during the same period, while both infections rose sharply in Lithuania and Malta.
Uneven testing obscures the scale of the problem
The figures may not fully reflect the actual prevalence of STIs across Europe, particularly in countries where surveillance and testing are limited.
In Romania, a country of 19 million people, only 24 cases of chlamydia were recorded in 2024 — an implausibly low figure and far below the number of reported syphilis cases.
Poor data makes it harder to justify investment in testing equipment while also limiting public awareness of the risks.
The ECDC says better surveillance is needed, including information on the proportion of vulnerable groups being tested in each country. Such data would allow reported infection rates to be assessed within the appropriate statistical context.
Only about one-third of European countries currently provide such information.
Antibiotic resistance adds another challenge
Countries with extensive STI testing face a different problem: antibiotic resistance.
Doctors treat STIs with antibiotics, which can contribute to the development of drug-resistant strains. Gonorrhea has already developed strains with high levels of antibiotic resistance, unlike chlamydia and syphilis.
Congenital syphilis, meanwhile, can be treated effectively, meaning its spread could be reduced through targeted testing during pregnancy.
Most European Union countries test women for syphilis during the first trimester of pregnancy. However, fewer than half follow recommendations to test women at higher risk during the third trimester or at delivery.
Hungary provides an example of how rising infection rates can prompt a stronger response. The country’s reported congenital syphilis cases rose from just three in 2020 to 91 in 2024, partly because of increased testing. The surge led authorities to introduce significantly stricter screening measures.
