Percent of Positive COVID-19 Viral Tests in Henderson. Data provided by Southern Nevada Health District. This snapshot provides data managed by the Nevada Department of Health and Human Services, Division of Public and Behavioral Health, Immunization Program for Clark County, NV, and assessed by the Southern Nevada Health District’s Office of Epidemiology and Disease Surveillance. Due to delays in processing and reporting, data from the most recent date are less complete than data from older dates. Data is preliminary and subject to change.