Infectious diseases – Sexually transmitted infections and chronic viral hepatitis

Record number of gonorrhoea cases, chlamydia decreased

In 2025, a record-high 2,097 gonorrhoea cases were reported to the Infectious Diseases Register. Women accounted for 34% and men for 66% of cases. The median age at diagnosis was 32 years. The increase in case numbers among men appeared to level off, with only a 4% rise compared with 2024. Among women, the increase continued, with 36% more cases than in the previous year. Between 2021 and 2025, gonorrhoea cases increased sharply: by 452% among women and by 264% among men.

The number of chlamydia cases continued the decline that began in 2024. In 2025, 11,712 chlamydia cases were reported to the Infectious Diseases Register, which is 2,774 cases (19%) fewer than in the previous year. Women accounted for 56% of cases and men for 44%. The median age at diagnosis was 24 years.

Number of HIV cases decreased by one fifth

In 2025, a total of 182 HIV cases were reported to the Infectious Diseases Register, 22% fewer than in the previous year. Women accounted for 39% and men for 61% of cases. The median age at diagnosis was 41 years.

A majority of cases (82%) were identified in people born abroad. Of these, 66% had been diagnosed with HIV before arriving in Finland. These cases are nevertheless recorded for the year in which the infection is first registered in Finland. The peak years for case numbers were 2022–2024, mainly linked to increased migration caused by the war in Ukraine.

The route of transmission was known for 67% of cases. Of these, 48% were heterosexual transmissions, 39% transmissions between men, and 10% associated with injecting drug use.

Key elements in controlling the HIV epidemic include early diagnosis, access to treatment, and treatment success. These data are collected in the HIV Register, which is one of the national quality registers.
HIV Register report 

Hepatitis C cases decreasing

In 2025, a total of 1,009 hepatitis C cases were reported to the Infectious Diseases Register, 9% fewer than in the previous year. Women accounted for 37% and men for 63% of cases. The median age at diagnosis was 35 years. Of all cases, 69% were in people born in Finland, and their case numbers decreased by 14% compared with the previous year.

A case recorded in the register is based on the detection of hepatitis C antibodies and/or nucleic acid. Notifications based on nucleic acid testing increased by 34% in 2025 compared with the previous year. Of these notifications, 21% were new cases. A new case refers to an individual for whom no previous hepatitis C notification has been made. Nucleic acid testing is important because it identifies active infections that require treatment.

The Hepatitis C elimination programme is included in the Government Programme. Its aim is to reduce morbidity and mortality caused by hepatitis C, as well as related costs and new infections. Injecting drug use was the reported route of transmission in 79% of cases with transmission information available. The programme aims in particular to reach people who inject drugs for testing and treatment.

Hepatitis B epidemic continued among people who inject drugs

In 2025, a total of 392 hepatitis B cases were reported to the Infectious Diseases Register. This represents a 12% decrease from the previous year. Women accounted for 39% and men for 61% of cases. The median age at diagnosis was 37 years.

In 2025, as in the preceding years 2022–2024, both the number and proportion of cases among people born in Finland were unusually high: 142 cases (36%). The increase is associated with transmission among people who inject drugs. Of all hepatitis B infections reported in people born in Finland in 2025, 70% were linked to injecting drug use (excluding cases with unknown information). People who inject drugs are eligible for free hepatitis B vaccination, and vaccination coverage must be improved.

Reporting services

Statistical cubes and summary reports of the Infectious Diseases Register

Background information

Privacy notice of the Infectious Diseases Register (in Finnish)

Privacy notice of the HIV Register (in Finnish)

Sources

The information is based on data from the Infectious Diseases Register and the HIV Register.

Statistical description

The Infectious Diseases Register is a national register maintained by the Finnish Institute for Health and Welfare (THL). It collects information on communicable diseases diagnosed in Finland. The primary purpose of the register is to monitor the occurrence of infectious diseases, prevent their spread, and support infection control efforts.

The HIV Register is a national register maintained by THL. Its purpose is to monitor the diagnosis, treatment and quality of care of HIV infection in Finland. It is part of the wider system of national health care quality registers. Data from the HIV Register are also used in monitoring the HIV epidemic.

Update schedule

The statistics page on sexually transmitted infections and chronic viral hepatitis is updated once a year, next in spring 2027.

Contact information