Serum Institute of India on Tuesday said its Covishield vaccine is safe and immunogenic and did not cause the neurological serious adverse effect in the 40-year-old participant from Chennai.“The incident with the Chennai volunteer, though highly unfortunate, was in no way induced by the vaccine and Serum Institute of India is sympathetic with the volunteer's medical condition," the company said in a statement.The conclusion that the vaccine had not caused the “acute neuro encephalopathy" in the patient was made by the principal investigator of Sri Ramachandra Medical College & Research Institute (SRMC)--Ramkrishnan, the Data and Safety Management Board (DSMB) and the Ethics Committee of the sites independently, the company said.However,.