COVID-19 Mega Vaccination Clinics: First come-First serve, No Pre-registration Patrick Johnstone/KRIS 6 News Long lines at the first day of COVID-19 vaccine distribution at the Richard Borchard Fairgrounds in Robstown. and last updated 2021-01-19 19:07:05-05 ROBSTOWN, Texas â Corpus Christi's City Manager Peter Zanoni has announced that future COVID-19 mega vaccination clinics at the Richard Borchard Fairgrounds in Robstown will be first come, first serve from now on. During the region's trial run last week, residents could either pre-register online, or register on-site to receive the vaccine. After the some re-assessing, Zanoni has clarified that pre-registration will no longer be an option, and all patrons will be registered on-site on a first come, first serve basis.