New Delhi: The central drug regulator has issued a show-cause notice to Serum Institute of India (SII) for not informing it about pharma giant AstraZeneca pausing the clinical trials of the Oxford vaccine candidate for COVID-19 in other countries and also for not submitting casualty analysis of the "reported serious adverse events".The show-cause notice was issued following reports that human trials of the most promising COVID-19 vaccine candidate, being developed by the University of Oxford, have been put on hold after a UK participant had an adverse reaction to it.The Drugs Controller General of India, Dr V G Somani, in his show-cause notice has asked SII as to why the permission granted for conducting phase 2 and 3 clinical trials of the.