Researchers from Sinopharm and its local partners in the Middle East say the trial involved around 40,380 participants with the company's two vaccines -- one developed by the Wuhan Institute of Biological Products and the other by the Beijing Institute of Biological Products -- and a placebo. The trial was carried out in four countries -- Bahrain, the United Arab Emirates, Egypt and Jordan. However, the study provided data for just Bahrain and the UAE. "There's nothing very surprising. It's consistent with what they have claimed previously, but it does not completely eliminate the doubts about Sinopharm," said Jin Dong-yan, a medical professor at the University of Hong Kong who was not involved with the study.