New Delhi: Union Health Minister Harsh Vardhan on Thursday expressed concern over the surge in COVID-19 cases in Delhi and pressed for mandatory retesting of all persons who test negative in rapid antigen tests and develop symptoms of Influenza-like illness and Severe Acute Respiratory Infection (SARI) later.He said false negative results of the disease might give way to complacency among the coronavirus infected.During a meeting, Vardhan interacted with Lt Governor Anil Baijal and Delhi Health Minister Satyendra Kumar Jain in presence of senior officials, mayors, municipal commissioners and district magistrates of the city.Vardhan expressed concern over the rise in number of cases and the high positivity rate in the North, Central,.