Denmark’s chlamydia cases among young people fell in 2024 after years of record highs, but with over 24,000 confirmed infections, the STI remains the country’s most common and experts warn low testing rates, especially among young men, may be hiding the real scale of infection.
The numbers tell a story of progress and persistent gaps. After Danish youth aged 15 to 29 set yet another unwanted record in 2022 with 35,687 confirmed chlamydia cases, the 2024 figures from Statens Serum Institut show a drop to 24,279. Measured across all age groups, it is the lowest count in a decade. Sex & Samfund compiled the data into a new municipal overview, and the pattern is clear: something has shifted.
But no one can say exactly what. According to SSI’s chief physician Steen Hoffmann, similar declines have been observed in England, Finland, the Netherlands, Ireland, Norway and Sweden. Representatives from all seven countries have discussed possible explanations. None found a definitive answer. The chlamydia bacterium has not changed, and diagnostic methods have not deteriorated.
The Testing Problem
The official drop may not reflect reality on the ground. In 2024, just 20.9 percent of young women and 8 percent of young men were tested. Yet young men had a positive rate of 17.1 percent compared to 9.5 percent among young women. That gap suggests a large hidden reservoir of untested and untreated infections among males.
Majbrit Berlau, general secretary of Sex & Samfund, pointed to a persistent myth. Some young men still believe chlamydia testing always involves an uncomfortable swab inserted into the penis. It does not. A simple urine sample works just as well.
Condoms Are Still Ignored
The organization’s new youth survey, SexLiv 2025, found that fewer than half of young Danes used a condom the last time they had sex with a new partner. Young men worry less than young women about catching an STI from a new partner. Condoms remain the only form of contraception that protects against sexually transmitted infections during penetrative sex.
I have watched this pattern repeat itself for years in Denmark. Young people know the theory but disregard the practice. The country offers some of the best sex education infrastructure in Europe, yet the gap between knowledge and behavior persists. Berlau emphasized the need to reach young people without resorting to outdated scare campaigns. The message should be that using condoms is caring, not fearful.
Political Will and Regional Gaps
For the first time in years, there is real political momentum behind chlamydia prevention. In 2024, the government and several parties agreed on funding to strengthen sexual health efforts, including expanded access to home testing kits. Sex & Samfund secured approval from Sundhedsstyrelsen for a project to roll out free home tests for 15 to 29 year olds nationwide. In 2025, all municipalities in Region Hovedstaden, plus Lolland and Kolding, already offer free home testing.
But geographic inequality remains stark. In 2024, Skive recorded the highest rate in Denmark with 28 cases per 1,000 young people. In Region Hovedstaden, Gentofte led with 26 cases, followed by Frederiksberg at 24 and Allerød at 22. Sorø topped Region Sjælland with 25 cases. The variation reflects differences in testing availability, local campaigns and possibly sexual behavior patterns among youth populations.
Berlau noted that with better political awareness and flexible testing options, Denmark now has a realistic chance of driving chlamydia down to a level where infections are caught early and do not lead to infertility.
Real Consequences for Real People
Untreated chlamydia can cause severe complications. Women face pelvic inflammatory disease, chronic pain and reduced fertility. Men risk inflammation of the epididymis. Both sexes can end up involuntarily childless. Many infections are asymptomatic, which is why routine testing matters so much.
Living here as an expat, I have seen how Denmark’s healthcare system excels at prevention when resources and political will align. The HPV vaccination program is a success story. Chlamydia could follow the same path if municipalities commit to sustained testing outreach and if young people, especially men, feel testing is normal rather than shameful.
KL, the association of Danish municipalities, has pushed for more systematic prevention across the country. A 2024 health proposal with 45 recommendations emphasized early intervention. The argument is both ethical and financial: preventing disease saves lives and reduces long term costs. Chlamydia may not be classified as a chronic illness, but its complications can burden municipal budgets through fertility treatments and prolonged medical care.
Sources and References
