Texas Governor Greg Abbott, whose state is engulfed in a fourth COVID surge, said he tested negative for COVID-19 on Saturday after having a “brief and mild” bout with the infection this week. In video posted on Twitter, the Republican governor, whose office announced four days ago that he had tested positive for the virus but was not experiencing symptoms, said he had been told that his illness was short and mild because he was vaccinated. His office added that he had received Regeneron’s COVID-19 monoclonal antibody treatment on Tuesday. The antibody treatment, containing antibodies casirivimab and imdevimab administered through an IV, has been reported to decrease the chances of hospitalization by 80 percent. Abbott encouraged Texans who have yet to be vaccinated to consider taking the shots. His office also said on Tuesday that the Regeneron treatment the governor took is “available at no cost to all Texans who get a doctor’s referral.” …