InfectRisk
Now · Week 15 / 2026

Respiratory illness in Italy

The three major respiratory pathogens side by side — influenza, COVID-19 and RSV — based on ECDC ERVISS weekly data from RespiVirNet (ISS).

Influenza
LowActivity level · Week 15
COVID-19
LowActivity level · Week 15
RSV
LowActivity level · Week 15

Current situation: Influenza

In week 15 of 2026, activity of influenza (seasonal flu) in Italy 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 data from Italy's RespiVirNet sentinel surveillance system run by the Istituto Superiore di Sanità (ISS). Seasonally, infection waves in Italy 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 Italy 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 Italy's RespiVirNet sentinel surveillance system run by the Istituto Superiore di Sanità (ISS). Seasonally, infection waves in Italy 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 Italy 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 Italy's RespiVirNet sentinel surveillance system run by the Istituto Superiore di Sanità (ISS). Seasonally, infection waves in Italy 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.

12-week trend
All three pathogens · Each curve on its own scale · Relative development
Week 04Week 07Week 10Week 12Week 15
Influenza
COVID-19
RSV

Data sources and methodology

The current picture for Italy is built on the European Respiratory Virus Surveillance Summary (ERVISS), published weekly by the European Centre for Disease Prevention and Control (ECDC). RespiVirNet (Istituto Superiore di Sanità, ISS) 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 Italy's case RespiVirNet (Istituto Superiore di Sanità, ISS) — 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

RespiVirNet (Istituto Superiore di Sanità, ISS) 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 Italy?

ISS's RespiVirNet system integrates flu, COVID-19, RSV, and other respiratory viruses into a single weekly bulletin. It combines sentinel primary-care incidence, hospital and ICU admissions for severe acute respiratory infection, and virological positivity. Italian data also feeds the ECDC ERVISS platform. On infectrisk.com we summarise the combined picture as a qualitative low/moderate/high classification.

Did Italy experience a “tripledemic”?

“Tripledemic” is a media label for the simultaneous winter circulation of flu, COVID-19, and RSV. Italy saw clear co-circulation of all three pathogens in the 2022–2023 season, with substantial pressure on paediatric care driven by RSV and on adult critical care. Co-circulation has continued in subsequent winters, though the relative intensity of each pathogen varies year to year.

Why do respiratory illnesses peak in an Italian winter?

Even with Italy's comparatively mild climate, winter drives a clear peak. Many respiratory viruses remain stable longer in cold, dry indoor air, heated buildings reduce humidity in ways that weaken airway defence, and people mix indoors more during the colder months. Schools and end-of-year 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 — for instance during strict COVID-19 measures — population-level immunity gradually declines and subsequent seasons can hit harder. Italy's post-pandemic RSV and flu seasons showed features consistent with this effect. It is a temporary catch-up phenomenon, not a permanent immune change.

How does ISS decide that activity is “high”?

ISS uses thresholds derived from historical RespiVirNet 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 the same time, the weekly bulletin classifies activity as high, using the same framework that structures Italy's ECDC ERVISS contribution.

Numbers · Personal risk · 36 countries

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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.

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Updated: 18/04/2026, 10:15