Respiratory Virus Cases Reach 1,024,659 in Argentina
Respiratory virus circulation across Argentina remains in decline following winter peaks, though the respiratory syncytial virus (VSR) maintains a clear predominance among hospitalized patients. Up to epidemiological week 37, the country accumulated 1,024,659 cases of influenza-like illness (ETI), representing a 3.3% increase compared to the same period in 2025. Health authorities attribute this year-on-year rise to an earlier start to the respiratory virus season.
Influenza Drops While VSR Dominates Hospital Admissions
During epidemiological week 38, the National Epidemiological Bulletin (BEN) indicated that influenza cases continue to fall with a higher relative presence of influenza B. Outlets reported minor variations in timing and metrics across surveillance updates: BEN report number 826 for epidemiological week 36 placed overall respiratory circulation within expected seasonal parameters, while outpatient influenza positivity temporarily ticked up to 18.6% due to delayed administrative data entry rather than active community spread. Across all reporting outlets, however, VSR consistently leads severe acute respiratory infections, heavily impacting infants under two years of age, particularly babies aged 6 to 11 months.
Outpatient sentinel surveillance detected just four influenza cases in the late-winter data, down sharply from previous weeks. During the ambulatory surveillance of epidemiological weeks 35 and 36, laboratories detected 33 cases of influenza out of 178 samples analyzed, representing an 18.2% positivity rate. Meanwhile, severe inpatient metrics highlight the ongoing burden of VSR. In the four weeks leading up to the BEN report, the surveillance network recorded 268 VSR-positive hospitalizations, compared to 42 influenza cases and six SARS-CoV-2 detections, alongside a small number of viral co-detections. During epidemiological week 36, authorities identified 61 cases of severe acute respiratory infections, while the first 36 weeks of the year accumulated 5,971 hospitalizations within the Argentine Sentinel Surveillance Network.
National Vaccination Strategy Targets Pregnant Individuals
To curb severe pediatric hospitalizations, the Ministry of Health maintains an active vaccination campaign. Faced with this epidemiological scenario, the Ministry of Health recommends keeping vaccination schedules completely up to date for influenza, SARS-CoV-2, pneumococcus, Haemophilus influenzae type B, Bordetella pertussis, and VSR, alongside standard general prevention measures. Since January 2024, the National Immunization Schedule includes the VSR vaccine for pregnant individuals between 32 and 36 weeks of gestation. This immunization transfers protective antibodies directly to the fetus, significantly lowering the risk of severe infant bronchitis and pneumonia during the baby’s first six months of life.
What Defines Influenza-Like Illness and VSR Positivity Rates?
What criteria define an influenza-like illness case in the national bulletin?
The surveillance system counts an illness as influenza-like when a patient presents with a fever of 38 degrees Celsius or higher, accompanied by a cough lasting less than ten days without any other identified cause.
Which age group experiences the highest positivity rates for VSR?
Infectious disease tracking shows that the impact of VSR concentrates heavily among children under two years old, with the highest positivity percentages occurring specifically in infants between 6 and 11 months of age.
How many total pneumonia notifications were recorded during the season?
The national surveillance system logged 127,046 cumulative pneumonia notifications up to epidemiological week 37, a figure slightly lower than totals recorded during the same timeframe in previous years.
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