Table 2 Overview of number of participants and collected materials in the study, by sample (n (%))
| Â | NS & oversampling of migrants | LVC sample | SAN sample | CN sample |
|---|---|---|---|---|
Sample invited | 40,065 | 6830 | 7275 | 8068 |
Net sample sizea | 39,898 (99.6%) | 6825 (99.9%) | 7252 (99.7%) | 7768 (96.3%) |
Information from population register only | 19,638 (49.0%) | 2436 (35.7%) | 4040 (55.5%) | NA |
Non-response questionnaire | 14,043 (35.2%) | 2964 (43.4%) | 2652 (36.6%) | NA |
Participant with any material | 6217 (15.6%) | 1425 (20.9%) | 560 (7.7%) | 1900 (24.5%) |
Full participant (all materials) | 2682 (6.7%) | 674 (9.9%) | 280 (3.7%) | 1515 (19.5%) |
Participant with both blood sample and questionnaire | 5745 (14.4%) | 1354 (19.8%) | 501 (6.9%) | 1815 (23.4%) |
Materialsb | ||||
 Bloodc   - Venous blood sample   - Finger/heel prick   - Dried blood spot sample | 5762 (92.7%) 4977 (86.4%) 581 (10.1%) 208 (3.6%) | 1358 (95.3%) 1174 (86.5%) 162 (11.9%) 23 (1.7%) | 503 (89.8%) 454 (90.3%) 25 (5.0%) 26 (5.2%) | 1829 (96.3%) NA NA 1829 (100%) |
 Questionnaire | 6200 (99.7%) | 1421 (99.7%) | 558 (99.6%) | 1885 (99.2%) |
 Saliva sample | 5544 (89.2%) | 1319 (92.6%) | 477 (85.2%) | NA |
 Nasopharyngeal swab | 3849 (61.9%) | 939 (65.9%) | 369 (65.9%) | 1752 (92.2%) |
 Oropharyngeal swab | 3319 (53.4%) | 791 (55.5%) | 326 (58.2%) | 1502 (79.1%) |
 Faeces | 2765 (44.5%) | 704 (49.4%) | 285 (50.9%) | 1547 (81.4%) |
 Additional questionnaire | 2775 (44.6%) | 702 (49.3%) | 284 (50.7%) | NA |
 Vaccination statusd | 3819 (71.1%) | 970 (76.3%) | 263 (57.9%) | 974 (51.3%) |
 Diary contact patternse | 1310 (72.7%) | NA | 67 (48.9%) | NA |
 Consent to approach for follow-upd | 5105 (82.1%) | 1171 (82.2%) | 436 (77.9%) | 1762 (92.7%) |