Respiratory illness in Spain
The three major respiratory pathogens side by side — influenza, COVID-19 and RSV — based on ECDC ERVISS weekly data from SiVIRA (ISCIII).
Current situation: Influenza
In week 15 of 2026, activity of influenza (seasonal flu) in Spain is low. The trend — derived from clinical surveillance — is stable. Over a four-week comparison, a clear decline is visible.
The classification is based on the ECDC ERVISS weekly reports, drawing on data from the Spanish SiVIRA acute respiratory infection surveillance system operated by the Instituto de Salud Carlos III (ISCIII). Seasonally, infection waves in Spain typically peak between December and February; activity is usually markedly lower during the summer months. How severe a given season becomes depends on the circulating virus variant and the population's immune status, among other factors.
Current situation: COVID-19
In week 15 of 2026, activity of COVID-19 in Spain is low. The trend — derived from clinical surveillance — is falling. Over a four-week comparison, a clear decline is visible.
The classification is based on the ECDC ERVISS weekly reports, drawing on COVID-19 indicators from Spain's SiVIRA surveillance system operated by the Instituto de Salud Carlos III (ISCIII). Seasonally, infection waves in Spain typically peak during winter, with occasional summer waves driven by new variants; activity is usually markedly lower in late spring between waves. How severe a given season becomes depends on the circulating virus variant and the population's immune status, among other factors.
Current situation: RSV
In week 15 of 2026, activity of respiratory syncytial virus (RSV) in Spain is low. The trend — derived from clinical surveillance — is falling. Over a four-week comparison, a clear decline is visible.
The classification is based on the ECDC ERVISS weekly reports, drawing on RSV indicators from Spain's SiVIRA surveillance system operated by the Instituto de Salud Carlos III (ISCIII). Seasonally, infection waves in Spain typically peak between December and February; activity is usually markedly lower in spring and summer. How severe a given season becomes depends on the circulating virus variant and the population's immune status, among other factors.
Data sources and methodology
The current picture for Spain is built on the European Respiratory Virus Surveillance Summary (ERVISS), published weekly by the European Centre for Disease Prevention and Control (ECDC). SiVIRA (Instituto de Salud Carlos III, ISCIII) is the national public-health authority that feeds ERVISS with sentinel primary care and virology data.
ECDC ERVISS
ERVISS is ECDC's weekly pan-European surveillance summary for influenza, SARS-CoV-2 and RSV. National authorities — in Spain's case SiVIRA (Instituto de Salud Carlos III, ISCIII) — submit harmonised indicators every week, which ECDC publishes in a standardised dataset on Thursdays. Using ERVISS rather than each country's native portal ensures cross-country comparability.
ILI / ARI consultation rates and positivity
SiVIRA (Instituto de Salud Carlos III, ISCIII) operates a sentinel network of general practices that report weekly rates of patients consulting for influenza-like illness (ILI) or acute respiratory infection (ARI). A subset of patients is swabbed and tested by reference laboratories, producing pathogen-specific positivity rates for flu, SARS-CoV-2 and RSV.
Why this source
Combining consultation incidence with virological positivity yields a pathogen-specific weekly incidence signal (ILI × positivity / 100). This is the standard European methodology and provides a more robust view than either indicator alone — consultation rates capture illness burden, positivity confirms which pathogen is driving it.
Qualitative classification
The “low”, “moderate” and “high” categories follow seasonal reference values and epidemiological thresholds calibrated to match our classifications for other countries. The ILI × positivity / 100 product is scaled to comparable thresholds using a divisor of 3, which aligns European sentinel peaks with the consultation-equivalent scale used elsewhere. Data refreshes weekly when ECDC publishes the latest ERVISS update, typically on Thursdays.
Frequently asked questions
How is overall respiratory-illness activity tracked in Spain?
ISCIII's SiVIRA system integrates flu, COVID-19, RSV, and other respiratory viruses into a single weekly bulletin. It combines sentinel primary-care data, hospital and ICU admissions for severe acute respiratory infection, and virological positivity. Spanish data also feeds the ECDC ERVISS platform. On infectrisk.com we summarise this into a qualitative low/moderate/high classification.
Did Spain experience a “tripledemic”?
“Tripledemic” is a media label for the simultaneous winter circulation of flu, COVID-19, and RSV. Spain saw clear co-circulation of all three pathogens in the 2022–2023 season, with strong pressure on paediatric care driven by RSV and on adult critical care. Co-circulation has continued in subsequent winters, with the relative intensity of each pathogen varying season to season.
Why do respiratory illnesses peak in a Spanish winter?
Even in Spain's milder climate, winter drives a clear peak. Many respiratory viruses remain stable longer in cold, dry indoor air, heated buildings lower humidity in ways that weaken airway defence, and people mix indoors more during winter. Schools and holiday gatherings accelerate transmission just as seasonal immunity is at its lowest.
What is “immune debt”?
“Immune debt” describes how, after prolonged low circulation of a pathogen, such as during the strict COVID-19 restrictions, population-level immunity gradually declines and subsequent seasons can be unusually severe. Spain's post-pandemic RSV and flu seasons showed features consistent with this effect. It is a temporary catch-up phenomenon rather than a permanent immune change.
How does ISCIII decide that activity is “high”?
ISCIII uses thresholds derived from historical SiVIRA data. Current sentinel incidence, hospitalisations, ICU admissions, and positivity rates are compared against baselines from past non-epidemic weeks and against severe-season reference points. When several indicators cross into elevated bands at once, the weekly bulletin classifies activity as high, using the same framework that structures Spain's ECDC ERVISS contribution.
Want the actual numbers?
You'll find them in the app.
Here you only see the trend. In the app: exact incidence rates, “X out of 100 people infectious”, your personal risk based on age and pre-existing conditions, wastewater trends, 36 countries, home-screen widget.
