Age (years) | 1997 | 1998 | 1999 | 2000 | 2001 | 2002 | 2003 | 2004 | 2005 | % Reduction (p value*) |
<1 | ||||||||||
Total (N) | 3081 | 2904 | 2779 | 3238 | 3901 | 3676 | 3664 | 4073 | 4094 | 63% (p<0.001) |
Varicella (n) | 8 | 33 | 28 | 23 | 16 | 17 | 14 | 21 | 12 | |
Proportion (%) | 0.26 | 1.14 | 1.01 | 0.71 | 0.41 | 0.46 | 0.38 | 0.52 | 0.29 | |
1–4 | ||||||||||
Total (N) | 2760 | 2709 | 2761 | 3439 | 4940 | 4676 | 3980 | 4645 | 4448 | 94% (p<0.001) |
Varicella (n) | 28 | 48 | 44 | 10 | 9 | 11 | 7 | 3 | 4 | |
Proportion (%) | 1.01 | 1.77 | 1.59 | 0.29 | 0.18 | 0.24 | 0.18 | 0.06 | 0.09 | |
5–9 | ||||||||||
Total (N) | 1224 | 1308 | 1468 | 1933 | 2818 | 2935 | 2999 | 3477 | 3432 | 73% (p<0.001) |
Varicella (n) | 11 | 11 | 13 | 5 | 5 | 13 | 10 | 11 | 8 | |
Proportion (%) | 0.90 | 0.84 | 0.89 | 0.26 | 0.18 | 0.44 | 0.33 | 0.32 | 0.23 | |
10–14 | ||||||||||
Total (N) | 1014 | 1085 | 1267 | 2325 | 3513 | 3510 | 2580 | 3136 | 3144 | 62% (p = 0.044) |
Varicella (n) | 1 | 9 | 4 | 4 | 2 | 4 | 4 | 7 | 5 | |
Proportion (%) | 0.10 | 0.83 | 0.32 | 0.17 | 0.06 | 0.11 | 0.16 | 0.22 | 0.16 | |
Unknown age† | 51 | 14 | 43 | 212 | 434 | 475 | 0 | 313 | 147 | |
Total | ||||||||||
Total (N) | 8130 | 8020 | 8318 | 11 147 | 15 606 | 15 272 | 13 223 | 15 644 | 15 265 | 81% (p<0.001) |
Varicella (n) | 48 | 101 | 89 | 42 | 32 | 45 | 35 | 42 | 28 | |
Proportion (%) | 0.59 | 1.26 | 1.07 | 0.38 | 0.21 | 0.29 | 0.26 | 0.27 | 0.18 | |
Characteristics of cases | ||||||||||
Male/female (n) | 26/22 | 47/54 | 46/43 | 23/19 | 22/10 | 22/23 | 21/14 | 22/20 | 11/17 | |
Without underlying condition | 42 | 88 | 80 | 40 | 29 | 41 | 33 | 34 | 26 | |
Immunosuppressed/malnourished‡ | 3 | 8 | 8 | 2 | 2 | 4 | 0 | 7 | 2 | |
Other | 0 | 0 | 0 | 0 | 1 | 0 | 1 | 1 | 0 | |
Unknown | 3 | 5 | 1 | 0 | 0 | 0 | 1 |
Other, celiac disease, nephritic syndrome or diabetes.
*Fisher exact test, % reduction from 1997 to 1999 until 2005.
†There were no varicella cases in individuals of unknown age.
‡Immunosuppression due to leukaemia, disease requiring corticosteroid therapy or HIV.
N, total number of hospitalisations; n, number of varicella-related hospitalisations.