Monitoring COVID-19 and Influenza: The Added Value of a Severe Acute Respiratory Infection Surveillance System in Portugal

Table 4

Summary of severe acute respiratory infection cases, stratified by age group and diagnosis, North and Lisbon and Tagus Valley regions, 28 September 2021–22 May 2022 (n = 3,563).

	Number	%
Age (in years)
0–4	159	4.5
5–14	88	2.5
15–44	184	5.2
45–64	565	15.9
65–79	1,011	28.4
≥80	1,556	43.7
Diagnosis
Total SARI	3,563	—
Influenza-like illness	455	12.8
Cardiovascular diagnosis	986	27.7
Respiratory diagnosis	228	6.4
Respiratory infection	2,082	58.4

SARI: severe acute respiratory infection. The sum of SARI cases by diagnosis category does not equal the total SARI cases, as the case definition for SARI syndrome was based on ICD-10 codes and some codes, can fall into more than one diagnosis category.