Table 2 Proportion of infections caused by lineage-level mismatched influenza B viruses, compared with the vaccine strain, by season (2004/2005–2016/2017) in Italy
Season | Northern Hemisphere TIV B lineage (strain) | N. of B viruses characterized (%) | Prevalent B lineage in Italy (virus variant) | N. of lineage-level mismatched viruses in Italy (%) | Seasonal match (m)/ Mismatch (M) |
|---|---|---|---|---|---|
2004/2005* | Yam (Sha/361/02) | 94 (37) | Vic (Ill/13/05) | 67 (71) | M |
2005/2006* | Yam (Sha/361/02) | 43 (54) | Vic (Mal/2506/04) | 36 (84) | M |
2006/2007 | Vic (Mal/2506/04) | 17 (47) | Yam (Flo/4/06) | 13 (76) | M |
2007/2008* | Vic (Mal/2506/04) | 99 (38) | Yam (Ban/3333/07) | 80 (81) | M |
2008/2009 | Yam (Flo/4/06) | 10 (22) | Vic (Bri/60/08 + Mal/2506/04) | 7 (70) | M |
2009/2010 | Vic (Bri/60/08) | 30 (58) | Vic (Bri/60/08) | 1 (3) | m |
2010/2011* | Vic (Bri/60/08) | 303 (38) | Vic (Bri/60/08) | 31 (10) | m |
2011/2012 | Vic (Bri/60/08) | 37 (59) | Yam (Wis/01/10) | 24 (65) | M |
2012/2013* | Yam (Wis/01/10) | 488 (40) | Yam (Mas/02/12) | 21 (4) | m |
2013/2014 | Yam (Mas/02/12) | 19 (56) | Yam (Phu/3073/13) | 2 (11) | m |
2014/2015 | Yam (Mas/02/12) | 327 (54) | Yam (Phu/3073/13) | 6 (2) | m |
2015/2016* | Yam (Phu/3073/13) | 866 (61) | Vic (Bri/60/08) | 833 (96) | M |
2016/2017 | Vic (Bri/60/08) | 132 (74) | Yam (Phu/3073/13) | 126 (96) | M |
All seasons | 2465 (49) | 1247 (50.6) |