Here we describe a transmission of a Delta variant containing SARS-CoV-2 strain, between family members associated with events surrounding a wedding with 92 attendees, near Houston, Texas. Attendance required guests be fully vaccinated and took place outdoors in a large, open-air tent. To date, 6 individuals have tested positive for SARS-CoV-2, all patients were symptomatic, one patient severely enough to receive monoclonal antibody infusion treatment (Regeneron Pharmaceuticals Inc.) and one patient has died.
Encounter timings and viral sequence similarities suggest the strain containing the Delta variant was transmitted to wedding guests from two patients travelling from India. With no history of vaccine failure in these patients, our observations suggest these are true cases of vaccine breakthrough, mediated by the Delta variant.