|-
!Post-exposure PRN<br>unchanged
|4 non-casecases
|7 non-cases
|}
!Non-cases with<br>≥1 symptom‡
|26 non-cases
|11 non-casecases
|-
!Non-cases with<br>no symptom
|11 non-casecases
|24 non-cases
|}
::‡suggestive of subclinical infection
::χ<sup>2</sup> test ''p''<0.002