Table 2.
Distribution results of anti-HEV IgG according to year of sampling
| Years of sampling | HEV IgG |
All tested | Odds of prevalence (95% CI) | |
|---|---|---|---|---|
| Positive (%) | Negative | |||
| 2002 | 5 (4.50) | 106 | 111 | 0.05 (0.02 to 0.12) |
| 2003 | 6 (5.41) | 105 | 111 | 0.06 (0.03 to 0.13) |
| 2004 | 3 (2.56) | 114 | 117 | 0.03 (0.01 to 0.08) |
| 2005 | 5 (4.35) | 110 | 115 | 0.05 (0.02 to 0.11) |
| 2006 | 4 (3.74) | 103 | 107 | 0.04 (0.01 to 0.11) |
| 2007 | 3 (2.56) | 114 | 117 | 0.03 (0.01 to 0.08) |
| 2008 | 13 (11.71) | 98 | 111 | 0.13 (0.07 to 0.24) |
| 2009 | 8 (7.48) | 99 | 107 | 0.08 (0.04 to 0.17) |
| 2010 | 9 (8.11) | 102 | 111 | 0.09 (0.04 to 0.17) |
| 2011 | 4 (3.67) | 105 | 109 | 0.04 (0.01 to 0.10) |
| Total | 60 (5.38) | 1056 | 1116 | 0.06 (0.04 to 0.07) |
The odds of prevalence are calculated as the frequency of positive tests divided by the frequency of negative ones. 95% CI is calculated with the square root of the variance of the score statistic. The χ2 test for homogeneity provides evidence that the prevalence may significantly change in the different year of sampling (p for no difference across the period=0.057).