Waikato District Health Board ransomware disrupts healthcare across five hospitals

On 18 May 2021, ransomware caused a regionwide information-systems outage at Waikato District Health Board, disrupting clinical delivery across five New Zealand hospitals. Staff lost critical phone and patient-information access, postponed elective operations and outpatient appointments, and restricted emergency departments to urgent cases. Clinical teams relied on manual procedures and diverted some patients to other facilities. A staff-authored published clinical account and contemporaneous statements corroborate patient-care consequences.