TOKYO, Sept. 10 (Xinhua) -- A Japanese health ministry panel said on Friday whether there is a causal relationship between the deaths of three men and their inoculations using batches of Moderna Inc. COVID-19 vaccine doses was unable to determine based on the information so far.

People wait after receiving the Moderna COVID-19 vaccine at the Tokyo Metropolitan Government building in Tokyo on June 25, 2021. (File photo: AFP)

After stainless steel contaminants were found in some vials in one of the lots, Moderna and Takeda Pharmaceutical Co., which is in charge of sales and distribution of the U.S. biotechnology firm's vaccine in Japan, suspended the use of three batches of around 1.63 million vaccine doses. However, 500,000 shots were believed to have been already used.

Three men aged 38, 30, and 49 died after receiving their second shots. The incidents were recalled later as a precaution since although the shots administered to the three men did not belong to the lot number confirmed with the contaminants, they were manufactured on the same production line at the same time in Spain.

The two men in their 30s died three days after their inoculations with no underlying health conditions. The other one, who died only a day after receiving the shot, was allergic to buckwheat but had no other major diseases' records.

The panel said it would continue investigating the causes of their deaths.

Moderna and Takeda said when announcing the recall that since stainless steel was usually used in heart valves, joint replacements, and metal sutures and staples, injection of the particles identified in these lots in Japan probably would not result in increased medical risk.