Finland's influenza epidemic shows no sign of immediate decline as both primary care and hospitals report sustained high infection rates. The National Institute for Health and Welfare (THL) confirms that influenza A viruses, specifically the H1N1pdm09 and H3N2 subtypes, are currently dominant across all age groups.
"It briefly looked like a dip was coming, but now it appears that infections and visits to healthcare have increased again," said Niina Ikonen, a leading expert at THL. She noted that the situation is not unusual, as influenza A typically acts as the dominant virus earlier in the season, with influenza B infections more common later in the spring. Reported case numbers represent only a fraction of actual illness, as only a portion of those sick seek medical care and even fewer receive a confirmed laboratory diagnosis.
Healthcare System Under Pressure
The Helsinki and Uusimaa Hospital District (HUS) reports that influenza activity in the region began a new upward trend in mid-January. "The situation is still placing a significant burden on healthcare, and especially the elderly and those in risk groups are being hospitalized due to influenza," said Eeva Ruotsalainen, Assistant Chief Physician of infectious diseases at HUS. She clarified that while the number of influenza patients on specialized care wards is on a downward trend, the overall volume of hospitalizations corresponds to previous influenza seasons nationwide. The strain is felt across primary health centers and emergency departments, managing the influx of patients presenting with high fever, respiratory symptoms, and fatigue.
Co-circulation of Respiratory Viruses
The influenza virus is not the sole challenge for public health this winter. Ruotsalainen pointed out that COVID-19 continues to circulate, remaining a potentially severe illness for those over 65 and other risk groups, and still leading to hospital admissions. Furthermore, an RSV (respiratory syncytial virus) epidemic, which typically affects young children and the elderly, is expected to begin in late winter or early spring. This overlapping circulation of multiple respiratory pathogens complicates clinical diagnostics and stretches laboratory resources, as symptoms for influenza, COVID-19, and RSV can be similar, especially in their initial stages.
Vaccination Remains a Critical Defense
Public health officials strongly emphasize the continued importance of influenza vaccination. Ruotsalainen explained that elderly individuals and those with underlying medical conditions are more susceptible to severe influenza leading to hospitalization, partly because their immune response to the vaccine can be weaker. Age and chronic illnesses can reduce the protective antibody levels generated by the shot. However, the vaccine remains the best preventive protection against influenza and the severe disease it can cause. "This is why all healthy people in close circles should get the vaccine, because they get a better response from it and thus protect their own elderly and risk group relatives," Ruotsalainen stated. The Finnish vaccination program targets these groups, but uptake among the general working-age population is encouraged to create broader community protection.
A Look at the Virus Composition
The current epidemic is driven by two main types of influenza A. The H1N1pdm09 virus, often associated with the 2009 swine flu pandemic, is now a regular seasonal strain affecting younger adults more frequently. The H3N2 virus is notoriously known for causing more severe seasons, particularly among the very old and very young, and is often linked to higher hospitalization rates. Influenza B viruses, which are divided into lineages, have so far been reported only sporadically. THL and its European counterparts through the ECDC network continuously monitor the genetic evolution of these circulating strains to assess their match with the vaccine formulation, which is updated twice yearly for the Northern and Southern hemispheres.
Historical Context and Seasonal Patterns
Finland's current experience aligns with typical seasonal patterns observed across the Nordic region. The peak of the influenza season often occurs between weeks 52 and 8 of the following year. The intensity can vary significantly from year to year, influenced by factors such as the predominant virus type, population immunity levels from past infections or vaccinations, and weather conditions that affect indoor crowding. The post-pandemic period has seen altered circulation patterns for many respiratory viruses, making year-to-year comparisons more complex. However, the re-establishment of a more predictable winter epidemic for influenza was anticipated by epidemiologists.
Public Health Recommendations in Force
In light of the ongoing epidemic, THL reiterates standard public health advice. Individuals experiencing symptoms are advised to stay home, avoid contact with people in risk groups, and practice good hand and respiratory hygiene. The use of face masks in crowded indoor spaces or when visiting healthcare facilities is recommended for those with symptoms. Testing for influenza and COVID-19 is encouraged for those in risk groups or with severe symptoms to guide potential antiviral treatment. Antiviral drugs for influenza, such as oseltamivir, are most effective when administered early in the course of the illness and are an important tool for treating severe cases or preventing complications in hospitalized patients.
The coming weeks will be decisive in determining the duration and peak of this winter's epidemic. With the RSV season on the horizon, Finland's healthcare system prepares for a prolonged period of high demand, underscoring the perennial challenge of managing seasonal respiratory illness within the framework of a universal healthcare model. The situation serves as a reminder of the constant threat posed by infectious diseases and the importance of sustained investment in surveillance, vaccination programs, and resilient healthcare infrastructure, topics frequently debated in the Eduskunta's committees on social affairs and health.