First case of COVID-19 Delta variant confirmed in Nueces County View Comments The first case of the COVID-19 Delta variant in Nueces County has been confirmed by the Mayo Clinic Laboratories, the public health district announced on Friday. The county said the person the sample came from was a woman in her 30s or 40s who works as a health care worker and was fully vaccinated when she became sick in mid-June. The woman was tested and found to be a breakthrough case. She spread the virus to her other family members who were not vaccinated. She and her family have fully recovered.