American pharmaceutical company Merck has announced a recall about one million doses of a vaccine that might have been contaminated, including about 100,000 that are being sold in China.

The vaccine the company is calling back is B type Haemophilus influenza (Hib), a common vaccine mainly used for children. The company said when they were inspecting a factory in Pennsylvania in the United States, they found that one piece of the equipment might have been contaminated by a certain bacterium which may affect the quality of the vaccine produced. Though there is no evidence showing that the vaccine had already been compromised, the company still decided to recall all the relevant products made via that equipment.

A representative from Merck China confirms to local media that about 100,000 of Haemophilus Type b Conjugate Vaccine with the series code of "J2438″ are being sold in China. Merck has notified the Chinese government departments at various levels, their dealers and the disease control center and are working closely with them on the recall of the vaccine.

So far, there is no report on any negative effects of the vaccine in China.