Number of healthcare workers susceptible to varicella (comparison of recalled history of varicella with serological testing (n=2000))
| History of varicella | VZV assay negative | VZV assay positive | Total |
| Positive | 11 | 982 | 993 |
| Negative | 7 | 201 | 208 |
| Unknown | 18 | 763 | 781 |
| No answer | 0 | 18 | 18 |
| Total | 36 | 1964 | 2000 |









