No 41 - 2025

Gonorrhea in 2024

• A total of 5,112 cases of gonorrhea were registered in the Danish Microbiology Database (MiBa).
• 4,040 cases were reported to the Notification System for Infectious Diseases (clinical notifications).
• Women accounted for 29% of all cases, and men for 71%.
• Men who have sex with men (MSM) continued to represent the largest proportion of cases.
• Information about HIV status was available for 54% of the reported gonorrhea cases.
• 60% of HIV-negative MSM were receiving PrEP treatment.
• 18 of the women reported with gonorrhea were pregnant.
• A decline was observed in the number of gonorrhea cases among women and heterosexual men, especially in the younger age groups.
• An increase was seen among men who have sex with men and in the older age groups.

The national surveillance of gonorrhea in Denmark, conducted by the Statens Serum Institut (SSI), is based on data from the Danish Microbiology Database (MiBa) and clinical notifications via the SEI2 system. The notification system collects information such as mode of transmission, sexual orientation, country of infection, and HIV status, which are not included in the laboratory data.

Therefore, it is important that all cases of gonorrhea are also clinically reported, as this provides essential epidemiological knowledge that gives health authorities the necessary foundation for implementing targeted preventive efforts. In 2024, 79% of cases were reported via SEI2.

Overall, the number of gonorrhea cases has decreased, and the curve has flattened compared to the steep rise seen in 2021–2022. However, there continues to be an increase in the number of cases among men who have sex with men (MSM). In 2024, there was a decline among heterosexuals, particularly among younger individuals. The decline is likely due to a combination of behavioral changes (less sexual activity, more protection) and increased awareness following the rise in 2022, as well as public health campaigns by, among others, the Danish Health Authority and Sex & Samfund.

The vast majority of gonorrhea cases continue to be acquired in Denmark, with only 10% reported as infected abroad. The most common countries of reported infection were Spain, Germany, Thailand, France, the USA, and Italy.

It is optimistic that in 2024, a decrease in the number of gonorrhea cases in Denmark was observed. The much-desired “bend of the curve” has thus been achieved, and although the number of cases remains high, it is encouraging that especially young people appear to have changed behavior, leading to lower transmission. Among people aged 45 years and older, in contrast to younger groups, there was an increase in cases, suggesting less frequent use of protection.

The 2024 figures also show that women, in general, are better than men at getting tested. Among women, 8,262 per 100,000 were tested for gonorrhea, compared to 3,872 per 100,000 among men.

There continues to be a steep increase among MSM, and it is important that MSM who have not already been offered PrEP are offered it when diagnosed with a sexually transmitted infection.

In 2024, there was also an increase in the number of gonorrhea cases among pregnant women. It is especially important that gonorrhea in pregnant women is treated, as there is a risk of transmitting the infection to the child during birth.

Although the numbers are relatively small, sex workers with gonorrhea continue to be reported each year, likely reflecting men’s reluctance to use condoms when visiting sex workers.

The prevalence of azithromycin resistance fell from 6% in 2023 to 3.6% in 2024, whereas the ciprofloxacin resistance rate increased from 45% to 60%, which is the highest level since 2011.

In 2025, a case of ceftriaxone-resistant gonorrhea was detected in Denmark. The case was imported from Southeast Asia, where ceftriaxone resistance is known to be a problem. The case was identified quickly, demonstrating the importance of ongoing surveillance of resistance. So far, no additional cases have been found.

International guidelines for the treatment of gonorrhea recommend an injection of ceftriaxone 1 g, while the Danish guidelines currently recommend a smaller dose, 500 mg. This should be increased to 1 g to align with international recommendations and help prevent resistance.

A more detailed account of gonorrhea in 2024 can be found in the annual report.

(T.R. Pedersen, S. Hoffmann, Department of Bacteria, Parasites & Fungi; M. Wessman, Department of Infectious Disease Epidemiology and Prevention)

Limited access to measurement of pneumococcal antibodies at Statens Serum Institut

As of September 25, 2025, one of SSI’s pneumococcal antibody analyses: R-695 Streptococcus pneumoniae vaccination status (IgG), has been discontinued.

This analysis has been used to assess whether revaccination is needed for individuals previously vaccinated against Streptococcus pneumoniae. In connection with the updated recommendations for pneumococcal vaccination and revaccination, it has been determined that decisions regarding revaccination should be based solely on risk groups and the interval since the last vaccination.

(C. S. Jørgensen, Department of Virus and Microbiological Preparedness; S. Hoffmann, Z. B. Harboe, J. S. Jensen, Department of Bacteria, Parasites and Fungi)