An inspection team headed by a top health official left Beijing for Wuhan, capital of Hubei province, on Wednesday to verify that substandard vaccines produced by a company in the city were handled properly, the State Drug Administration said on Wednesday.

The team has members from the administration and several other government bodies, including the National Health Commission, and is headed by administration Party chief Li Li, it said.

More than 400,000 doses of substandard DTaP vaccine — meant to prevent diphtheria, tetanus and whooping cough in infants — was produced by Wuhan Institute of Biological Products Co and sold to Chongqing municipality and Hebei province, the administration said in November.

The administration said in a statement on Tuesday that a temporary malfunction of equipment on the company’s production line led to an uneven amount of liquid in vaccines being packaged, making them ineffective.

The company recalled all unused DTaP vaccines following the discovery of the problem and destroyed them under the supervision of the local drug authority in May, the administration said.

The company also improved quality control of its products and training for staff following the incident, and inspections conducted by the administration found all subsequent DTaP vaccines produced by the company met standards, it said.