Amid widespread concern over Thrombosis with Thrombocytopenia Syndrome - a rare side-effect of the Covishield COVID-19 vaccine - the Serum Institute - which made the drug developed by British pharma giant AstraZeneca - has said that all its product packaging had "disclosed all rare to very rare side-effects", including TTS. The vaccine's safety "remains paramount", the company said Wednesday, pointing out the drug, as Covishield, had been "instrumental in saving millions of lives worldwide".