Table 2. Annual incidence of emergency admissions with influenza-specific International Statistical Classification of Diseases, Tenth Revision (ICD-10) codes at any diagnosis position, including those with influenza polymerase chain reaction test.a.
| Year | Population | Admissions with influenza-specific ICD-10 codes at any diagnosis position | |||
| Total, n (per 100,000 population) | With influenza test | ||||
| Total, n (%) | Positive, n (per 100,000 population)b | Positivity (%)c | |||
| 2015 | 3,202,489 | 383 (12.0) | 217 (56.7) | 46 (1.4) | 21.2 |
| 2016 | 3,210,914 | 652 (20.3) | 446 (68.4) | 129 (4.0) | 28.9 |
| 2017 | 3,219,095 | 784 (24.4) | 465 (59.3) | 70 (2.2) | 15.1 |
| 2018 | 3,226,596 | 2078 (64.4) | 1395 (67.1) | 658 (20.4) | 47.2 |
| 2019 | 3,234,939 | 2526 (78.1) | 1890 (74.8) | 551 (17.0) | 29.2 |
| 2020 | 3,235,883 | 436 (13.5) | 299 (68.6) | 87 (2.7) | 29.1 |
| 2021 | 3,243,287 | 115 (3.5) | 98 (85.2) | 19 (0.6) | 19.4 |
For each year between 2015 and 2021, the table includes the population estimate for Wales, the total number of admissions with influenza-specific ICD-10 codes, the number of those admissions that match an influenza test collected within 7 days before or after admission date, the number of those admissions with positive tests, and test positivity. Admission records were extracted from the Patient Episode Database for Wales. Influenza test records were extracted from the Welsh Results Reports Service data source.
This column represents the case definition: emergency admission with an influenza-specific ICD-10 code at any diagnosis position and a positive influenza test.
Positivity % is the percentage of emergency admissions with influenza-specific ICD-10 codes and an influenza test where the test was positive.