As many as 40 Covid patients have taken a single-dose drug cocktail of monoclonal antibodies at Hyderabad's Asian Institute of Gastroenterology. "In 24 hours, they recovered from clinical symptoms like fever, malaise etc," said chairperson of the hospital, Dr Nageshwar Reddy. Hyderabad-based Asian Institute of Gastroenterology is carrying out one of the largest studies to find out if the therapy is effective against the highly infectious Delta variant.