By Ryan StewartFor to The OklahomanBrad Benefield hasn’t tested positive for COVID-19 since April. But as spring turned to summer, and now fall, Benefield is growing increasingly concerned about his bout with the virus known technically as SARS-CoV-2. “One thing everyone told me to do once I was symptom-free was to donate plasma to help others recover, or donate blood for antibody studies,” said Benefield, whose wife, Beth, works for the Oklahoma Medical Research Foundation.Read more on NewsOK.com