Moderna Inc's Covid-19 vaccine contamination woes in Japan have widened after two regions put temporary holds on shots following the discovery of foreign substances in more batches.

The disruption to Moderna supplies comes as Japan battles its worst wave of Covid-19 yet, driven by the contagious Delta variant, with new daily infections exceeding 25,000 this month for the first time amid a slow vaccine rollout.

The latest reports of vaccine contamination came from Gunma prefecture near Tokyo and the southern prefecture of Okinawa, prompting temporary holds on Sunday on shots from two new Moderna lots. That followed the nationwide suspension of 1.63 million doses last week.

A tiny black substance was found in a Moderna vaccine vial in Gunma, an official from the prefecture said, while in Okinawa, black substances were spotted in syringes and a vial, and pink material was found in a different syringe.

Read the full Reuters story here.