From 7 to 13 September 2026, influenza activity in Spanish primary care reached 8.2%, information from the ISCIII/SiVIRA surveillance system. The figure remains below the epidemic threshold, though it is higher than a year ago, and surveillance teams have seen a small rise among younger people. Álvaro Torres says international monitoring matters because changes in circulating viruses can appear in one region before reaching another. The data cannot offer a complete forecast, but they can give public health authorities more time to assess the risks of the next season.
The southern hemisphere may offer some of the clearest clues. Torres describes the study of circulating variants there as one of the strongest predictive indicators. The pattern does not always move neatly from south to north. Tropical regions follow a different rhythm because influenza can circulate throughout the year, and those areas may be both sources and destinations for transmission.
That uncertainty makes year-round surveillance necessary. Spanish weekly reports describe the current increase as limited and non-epidemic, with the clearest early changes among younger age groups.
Most detected viruses are influenza A. Hospitalised patients are mainly aged 65 or over. The early rise among younger people remains limited, but needs close monitoring. The start and strength of a flu season can change from one year to the next, information from the expert cited by Europa Press.
Severe cases still follow the usual seasonal pattern, with older adults bearing much of the hospital burden.
On 25 September 2026, the World Health Organization updated its recommended vaccine composition for the 2027 southern hemisphere influenza season. For egg-based vaccines, it recommended strains similar to A/Missouri/11/2025 (H1N1)pdm09, A/Darwin/1454/2025 (H3N2) and B/Tokyo/EIS13-175/2025 (B/Victoria). For cell-based and recombinant platforms, the recommendations were A/Missouri/11/2025, A/Darwin/1415/2025 and B/Pennsylvania/14/2025.
Those choices matter for Spain because vaccine composition is set well before the season begins. Laboratories in different countries supply the data. The WHO says its recommendations draw on global consultation and analysis of circulating viruses, rather than conditions in one country alone.
It is still too early to know how closely the vaccine will match the viruses that eventually spread in Spain. Torres says an inaccurate prediction means lower vaccine effectiveness.
The European picture extends beyond influenza. ECDC's ERVISS reports track influenza, RSV and SARS-CoV-2 across the EU/EEA and the WHO European Region. Recent updates place viral activity in the context of schools and workplaces reopening, although levels remain below epidemic thresholds.
Vaccination is not expected to prevent every infection. Its basic purpose is to reduce severe illness, hospital admissions and deaths linked to influenza. Raising coverage among vulnerable groups remains difficult.
Spain's surveillance network brings the autonomous communities together. It tracks more than positive tests: hospitalisations, bed occupancy and intensive care admissions, along with deaths, help show how severe a season is. Pharmacy sales of flu medicines and school absences can provide indirect signals.
Prevention also connects with access to care, discussed in an earlier health report, though this article focuses on influenza tracking rather than treatment.
People and animals move. Climate shifts and bird migration can change how viruses circulate. Surveillance systems can spot small changes earlier, but the data matter only when they guide prevention and response decisions.
Torres says every public health intervention needs assessment before it starts and evaluation afterwards. That keeps surveillance tied to action.
The indicators show where the virus is circulating, which groups are affected and how much pressure reaches hospitals. Health authorities can then adjust their response instead of following a fixed seasonal script. Spain's current activity remains below epidemic levels.
Influenza preparedness does not depend on a perfect prediction. It depends on an international network that can detect imperfect signals early. Spain's low activity is no reason to stop watching: variant tracking, hospital data and vaccine planning still leave time to shape a measured response before the season's real burden becomes clear.
