Under investigation - A case which has been notified but information is not yet available to classify it as probable or confirmed.

Probable - A clinically compatible illness with detection of a positive antigen test in CSF
OR
a confident diagnosis of epiglottitis by direct vision, laryngoscope or X-ray.

Confirmed - A clinically compatible illness that is laboratory confirmed.

Not a case - A case that has been investigated, and subsequently has been found to not meet the case definition.

For more information refer to the Haemophilus Influenzae type b invasive disease section of the Communicable Disease Control Manual.