Anvisa halts CoronaVac studies after “grave adverse event”

Brazil’s national sanitary watchdog Anvisa reported in a note it has halted the clinical studies on vaccine CoronaVac, one of the vaccines against the novel coronavirus being studied. The suspension occurred due to a “grave adverse event.” No further details on the incident have been provided. It could range from the hospitalization of a volunteer to their death.

The adverse event is reported to have taken place on October 29. Now, the agency will make a decision based on a risk-benefit analysis of continuing studies. This kind of suspension, Anvisa stated, is part of the procedures of Good Clinical Practices for studies conducted in Brazil.

“With the study interrupted, no new volunteer may be vaccinated. Anvisa reiterates that, according to national and international regulations of Good Clinical Practices, data on volunteers in clinical studies must be kept secret, in compliance with principles of confidentiality, human dignity, and protection of participants,” the agency added in a note.

CoronaVac is being developed by Chinese pharmaceutical firm Sinovac in partnership with São Paulo’s Butantan Institute. Ten days before the “grave adverse event” was notified, it was considered the safest vaccine of all those tested, according to Butantan Director Dimas Covas.