There were 2150 close contacts and 3775 casual plus contacts identified during the outbreak. The new contact categories were developed for “what boiled down to only two extra requirements”. The extra complexity for only two changes was “excessive”, the advisory group found. Individuals in an outbreak simply need to know if they are a close or casual contact and what, during that particular outbreak, is expected of them. While the new categories were supposed to increase clarity, “ironically, they facilitated blurring of the boundaries” between them, “increasing confusion” – such as when 1600 casual contacts were relabelled close contacts. At the time, the Ministry of Health said the additional classification of casual plus helps “provide flexibility in terms of the public health response to public exposure events as well as help standardise the approach for health services”.