Pfizer has cut its delivery targets for its coronavirus vaccine because of supply chain problems, according to a newspaper.

Now half the original amount is expected, reported the Wall Street Journal on Thursday.

The background is an insufficient quality of the raw materials.

A statement from the US pharmaceutical company was initially not available.

Pfizer is developing the vaccine together with Biontech from Germany.

The news weighed on US trading on Pfizer stock, which was just 2.4 percent in the red shortly before the close of trading on Wall Street. The US standard value index Dow Jones gave up its initial gains.