A volunteer in the local Peruvian trial of a coronavirus vaccine produced by China’s Sinopharm Group Co Ltd has died from COVID-19 related pneumonia, the university carrying out the trial said on Tuesday.

Cayetano Heredia University, which is involved with the study, said that it did not know if the volunteer had received the vaccine or the placebo in the double blind trial. Peru is being hit by a second wave of COVID-19 infections.

“We regret to announce that one of our volunteers died as a result of COVID-19 pneumonia. It is a painful loss for which we extend our condolences to her family,” the university said in a statement.

“She received all the care indicated to treat this disease and her complications, and she was fighting for her life for more than a week.”

The university added that it had communicated the case to the study’s safety committee and to regulatory authorities for an investigation to take place. It did not mention whether there would be any halt to the trial.

“Cases of infection or deterioration in participants receiving a placebo correspond to what would occur in the non-immunized population,” the university said, adding such cases in participants who had received a vaccine “may occur because the efficacy of them is not 100%”.

In December, Peru temporarily suspended trials of the Sinopharm COVID-19 vaccine due to a “serious adverse event” that occurred with a volunteer in the study.

In Brazil clinical trials of China’s Sinovac COVID-19 vaccine were suspended before being allowed to resume late last year due to a study subject’s death that was registered in Sao Paulo as a suicide.

Reporting by Marco Aquino; Writing by Adam Jourdan / REUTERS