Serum Institute of India has threatened to file a defamation suit against a participant who reported having adverse reactions after receiving a dose of the company's test Covid-19 vaccine during a clinical trial in India.
An official at the Indian Council of Medical Research (ICMR), a co-sponsor of the vaccine trial along with Serum Institute, said the Drug Controller-General of India (DCGI) is investigating.
A 40-year-old trial participant was admitted to a Chennai hospital for 15 days in October after experiencing severe neurological reactions 10 days after receiving a dose of Covishield, as the vaccine made by the Pune-based Serum Institute is called.
The vaccine technology was developed by Oxford University and British-based AstraZeneca, and Serum Institute is conducting a Phase 2/Phase 3 trial on 1,600 volunteers in India. The privately owned Indian company is the world's largest vaccine manufacturer.
Dr S. Ramakrishnan, the principal investigator who administered the vaccine in Chennai on Oct 1, told The Straits Times that the patient was treated from Oct 12 to 26 at the same hospital where he received the vaccine.
His condition was diagnosed after multiple tests as acute encephalopathy, which alters brain function and causes personality change, memory loss and declining ability to reason or concentrate.
The patient's wife said the marketing consultant is now recovering at home but suffers from weakness and mild mood swings.
Dr Ramakrishnan said the illness was "unrelated to the vaccine" and that the local institutional ethics committee agreed with him in its initial assessment.
But the participant's wife charged: "The hospital did many tests and bore all the costs, but they were trying to find some reason for my husband's illness that was not the vaccine. Even the hospital's discharge summary didn't mention the vaccine under medication history."
The discharge summary, a copy of which ST has seen, lists existing gastroenteric issues and a hair-loss tablet the man has taken for a year, but not the trial vaccine dose he got 10 days prior to falling ill.
The participant's family filed a legal notice against the company and India's drug regulator on Nov 21, demanding compensation of 50 million rupees (S$903,800) and that the vaccine trial be stopped until the government investigation shows it is safe.
Serum Institute on Sunday dismissed the participant's allegation as "malicious and misconceived". In a statement, the company said it would seek damages in excess of a billion rupees.
Dr T. Jacob John, a leading virologist and former professor at the Christian Medical College, Vellore, said the Serum Institute's statement was "completely out of line", especially given that the Covishield vaccine could be given to millions.
"The company cannot prematurely declare that the adverse event is not related to the vaccine until the official agency concludes its evaluation… The adverse event should have been in the public domain by mid-October when the man was hospitalised."
AstraZeneca vaccine trials were paused worldwide, including in India, in September after two participants in the trial in Britain suffered adverse events. The trials were resumed only after one investigation concluded that the adverse event was unrelated to the vaccine, while the other investigation was inconclusive.