D. COVID-19 Outbreak Investigation and Reporting

II. COVID-19 General FAQs

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D. COVID-19 Outbreak Investigation and Reporting


HCA defines a COVID-19 outbreak as 3 or more laboratory-confirmed cases among employees who live in different households present within a 14 day period that are epidemiologically linked.

This definition applies to:

  • Work sites
  • Schools (including preschools, K-12, and colleges/universities)
  • Social groups (parties, church gatherings, etc.)

Note: the definitions above adhere to California Department of Public Health Guidance. They may be updated in the future as guidance changes.

An outbreak occurs when COVID-19 is spread to multiple persons in a community setting. If multiple cases are identified in persons at one community site or group, but the cases are not linked epidemiologically and were acquired outside of the site, HCA will assist with preventing new cases, but this is not an outbreak.


COVID-19 outbreaks occur in multiple community settings (e.g., work sites, schools, churches, congregate living, etc.). A primary public health focus is prevention of spread in these settings. It is the responsibility of every employer to protect the health and wellbeing of their workers and knowing what to do in the event of an outbreak. It is a requirement for every employer to notify HCA if there is a known or suspected outbreak in the workplace. HCA will assist in investigating whenever multiple cases are identified at a public site.


HCA should be informed whenever 3 or more cases are identified in a specific work or social group within a 2 week period.


HCA should be informed whenever 3 or more cases are identified in a specific class, work or social group within a 2 week period.


An outbreak can be reported to HCA by calling the OC Health Care Agency's Health Referral Line toll free at 1(800) 564-8448.