Table 2– Summary of the information available on nationality of the index case in mixed clusters and on the likely direction of transmission between foreign-born and native-born cases.
| Author | Mixed clusters with identified index case/total number of mixed clusters | Foreign-born index case/total n identified index cases with known nationality | Native-born infected by foreign-born/native-born in mixed clusters | Foreign-born infected by native-born/foreign-born in mixed clusters |
| Allix-Béguec [20] | 10/17 (58.8) | 7/10 (70) | 17/24 (70.8) | 3/28 (10.7) |
| Barniol [21] | 16/16 (100) | 9/16 (56.3) | NA | NA |
| Borrell [23] | 22/22 (100) | 10/22 (45.5) | NA | NA |
| Dahle [25] | 9/9 (100) | 3/9 (33.3) | NA | NA |
| Diel [26] | 10/20 (50) | 9/10 (90) | 55/61 (90.2) | 3/24 (12.5) |
| Gil [28] | 12/12 (100) | 5/12 (41.7) | NA | NA |
| Inigo [30] | 40/40 (100) | 20/40 (50) | 38/123 (30.9) | 28/64 (43.8) |
| Kamper-Jørgensen [31] | 105/105 (100) | 50/105 (47.6) | NA | NA |
| López-Calleja [33] | 5/5 (100) | 2/5 (40) | NA | NA |
| Lucerna [34] | 18/18 (100) | 15/18 (83.3) | 22/32 (68.8) | 6/34 (17.6) |
Data are presented as n (%). NA: not available.