RSV activity in Portugal
Current respiratory syncytial virus (RSV) activity in Portugal — based on ECDC ERVISS weekly data from the Instituto Nacional de Saúde Doutor Ricardo Jorge (INSA).
Current situation: RSV
In week 15 of 2026, activity of respiratory syncytial virus (RSV) in Portugal is low. The trend — derived from clinical surveillance — is stable.
The classification is based on the ECDC ERVISS weekly reports, drawing on RSV surveillance data from the Instituto Nacional de Saúde Doutor Ricardo Jorge (INSA) via the Médicos-Sentinela network. Seasonally, infection waves in Portugal 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 Portugal is built on the European Respiratory Virus Surveillance Summary (ERVISS), published weekly by the European Centre for Disease Prevention and Control (ECDC). the Instituto Nacional de Saúde Doutor Ricardo Jorge (INSA) via the Médicos-Sentinela network 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 Portugal's case the Instituto Nacional de Saúde Doutor Ricardo Jorge (INSA) via the Médicos-Sentinela network — 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
the Instituto Nacional de Saúde Doutor Ricardo Jorge (INSA) via the Médicos-Sentinela network 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
When is RSV season in Portugal?
RSV in Portugal typically returns in late autumn, rises through November and December, and peaks between December and February before fading in spring. Portugal's mild Atlantic climate can produce somewhat broader and less sharp peaks than in colder continental countries. INSA tracks RSV activity within its weekly respiratory-virus surveillance alongside flu and SARS-CoV-2.
Who is most at risk from RSV in Portugal?
The groups at highest risk of severe RSV are infants — especially those under six months, preterm babies, and children with underlying heart or lung disease — and older adults, particularly those aged 75 and above or with chronic respiratory or cardiac conditions. RSV is the leading cause of bronchiolitis hospitalisations in Portuguese infants. In otherwise healthy children and adults, RSV usually resembles a common cold.
Are RSV vaccines available in Portugal?
Since 2023, RSV vaccines have been authorised in the EU for older adults, and the long-acting monoclonal antibody nirsevimab is available for infants. Portugal has progressively introduced nirsevimab for infants entering their first RSV season and adult RSV vaccination for defined risk groups, guided by recommendations from the Direção-Geral da Saúde. INSA monitors uptake and paediatric hospitalisation trends.
How is RSV surveillance organised in Portugal?
Portuguese RSV surveillance combines sentinel-laboratory testing, sentinel GP data via the Médicos Sentinela network, and hospital-admission signals coordinated by INSA. Virological characterisation is performed by the National Reference Laboratory for Influenza and Other Respiratory Viruses. Weekly results feed INSA's respiratory-virus bulletin and ECDC ERVISS, which makes Portugal's RSV curve directly comparable with Spain and EU/EEA neighbours.
How does RSV differ from flu in Portuguese data?
In INSA's respiratory panel, flu and RSV appear as distinct positivity streams. RSV disproportionately affects infants and the very elderly and is the main driver of paediatric bronchiolitis admissions, while flu burden spreads across age bands and is especially severe in older adults. Symptom overlap between the two viruses is wide, so the distinction is drawn from laboratory testing rather than clinical impression.
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