The national incidence of influenza in primary care has fallen for the fourth consecutive week, with the positivity rate now at 22% (previous week: 29.4%); similarly, the rate of hospitalization for this reason has also fallen, now at 3.6 cases per 100,000 inhabitants, while This was not the 6.9 cases the previous week.
This is reflected in the weekly report of the Surveillance System for Acute Respiratory Infections (Sivira) released this Thursday by the Carlos III Health Institute, which covers data from the fourth week of this year (January 22 to 28).
Influenza activity declined in all boroughs, across all age groups, and in hospitalizations, but the highest rates were seen in patients aged 80 years or older.
In terms of severity, since the start of the season, 36.2% of cases hospitalized with influenza have developed pneumonia, 5.6% have been admitted to the intensive care unit, and 6.4% have died. Case fatality rates for influenza hospitalizations are higher than last season.
The incidence of respiratory tract infections is reduced by 18.7%
Globally, the incidence of acute respiratory infections (ARI) in primary care fell to 587.3 cases per 100,000 inhabitants (compared to 722.1 cases in the previous week), a decrease of 18.7%. All autonomous regions saw declines.
By age group, the highest incidence of acute respiratory infections in primary care was in the group of children under 1 year old (3,102 cases/100,000 inhabitants), followed by the group of children 1-4 years old (2,145.3 cases).
Like influenza, the SARS-CoV-2 positivity rate has also decreased (6.3% compared to 8.3% the previous week). Respiratory syncytial virus (RSV) has stabilized at 7.5% (7.3% the previous week).
Nosocomial severe respiratory infection (SARI)
The hospital incidence of severe acute respiratory infections (SARI) has dropped to 16.4 cases per 100,000 inhabitants, compared with 23.7 cases per 100,000 inhabitants the previous week.
By age group, the highest hospitalization rate this week was among adults aged 80 or older (107.4 cases per 100,000 residents), followed by the group of children under one year old (86.4 cases).
The hospitalization rate for Covid-19 is 1.4 per 100,000 inhabitants (compared to 1.8 the previous week) and is trending downward. Hospitalizations due to the disease fell across all age groups except children under one, with a hospitalization rate of 18.2.
Similarly, the rate of hospitalizations due to RSV infection has also decreased, with 2 cases per 100,000 inhabitants (compared to 2.2 cases in the previous week).
A decrease was seen in all age groups except those aged 1-4 years (5.8 cases per 100,000 inhabitants compared with 3.6 cases). In terms of severity, since the start of the season, pneumonia has accounted for 20.8% of hospitalizations for RSV infection, 10.8% have been admitted to the ICU, and the mortality rate has been 2.7%, similar to the ranges seen in previous seasons.