Late-stage vaccine trials resume after Brazil pause

After a brief pause, Brazil has restarted late-stage trials for a COVID-19 vaccine candidate developed by Chinese drugmaker Sinovac Biotech.

Brazilian health regulator Anvisa said in a statement on Wednesday that it had evaluated enough information "to allow the resumption of vaccination". The trials of the candidate vaccine, CoronaVac, had been suspended after "serious adverse event," believed to be the death of a volunteer.

"It is important to clarify that a suspension does not necessarily mean that the product under investigation lacks quality, safety or efficacy," the regulator said.

Anvisa paused the vaccine trial on Monday after reports linked it to the death of the trial participant on Oct 29. Reports described as unfounded have been refuted, and the related data was said to have met health requirements.

The Brazilian police said the death of the trial volunteer resulted from suicide and was unrelated to the vaccine, Xinhua reported.

Pearson Liu, director of brand management and public relations at Sinovac, said in a statement on Tuesday that the person's death was not related to the vaccine. "Sinovac will continue to communicate with Brazil on this matter ... we are confident in the safety of the vaccine."

Sinovac is working with its Brazilian development partner, the Butantan Institute, a public research institute in Sao Paulo. In a statement on Wednesday, Sinovac said the stoppage of the trial was caused by a miscommunication.

"We have learned that Anvisa failed to receive the data sent by Butantan Institute in time, and it urgently suspended the clinical study Nov 9," Sinovac said."Butantan Institute communicated with Anvisa on Tuesday, and the report from Data and Safety Monitoring Board was submitted to Anvisa on the same day."

"After evaluating the new data, Anvisa made a very timely decision to resume the clinical research."

The Chinese Foreign Ministry's spokesman, Wang Wenbin, said on Thursday that China is pleased to see the resumption of the vaccine's clinical trials. He told a news briefing that China has always highly prioritized the safety and efficacy of COVID-19 vaccines and strictly abides by international norms and laws and regulations.

Positive contributions

Wang added that China believes that the cooperation between China and Brazil on COVID-19 prevention will make positive contributions in the global fight against the pandemic.

Anvisa approved phase III trials for CoronaVac on July 3. Around 9,000 people have been recruited. The Butantan Institute said in late October that it had received Anvisa's approval to import enough raw materials to produce 40 million doses of CoronaVac.

"This is another important step toward making CoronaVac available, which will be applied only after Anvisa's approval and registration as soon as the safety and effectiveness results are proven," the institute said in a statement.

The writer is a freelance journalist for China Daily.