The World Health Organization (WHO) on Friday expressed concern over recent infant deaths in China that were linked to hepatitis B vaccination, saying it will support the government's investigation into the cases.

At least 12 deaths have been reported since November after infants were vaccinated with hepatitis B shots produced by different companies in China. Health authorities are focusing on Shenzhen drug manufacturer BioKangtai, whose vaccines have been associated with most of the infant deaths.

The WHO supports China's decision to temporarily suspend use of the hepatitis B vaccine from the vaccine maker and investigate the cases, according to a statement from the organization's website.

"These deaths are very unfortunate, but the rapid reporting and investigation of the government speaks to the strength of the health and drug regulatory system to identify adverse events quickly and take action to prevent additional problems," said Dr. Bernhard Schwartlander, WHO Representative in China.

All Chinese infants receive the first dose of the hepatitis B vaccine within 24 hours of birth, with two additional doses at one month and six months respectively.

"The health gains of the vaccination program are enormous and all the efforts should be directed towards the continuation of the vaccination program while ensuring the safety of the vaccines," according to the official.

The hepatitis B vaccine program in China has been responsible for the reduction of the prevalence of hepatitis B to less that 1 percent among children under 5 years old, down from over 9 percent in the pre-vaccine era, the statement added.

The hepatitis B vaccine produced by other five manufacturers in China is still available, so there is no risk of shortage, according to the China Food and Drug Administration.

The WHO will continue to work very closely with Chinese health and drug authorities to support the investigation and to ensure that, during this period, the best guidance and advice on immunization can be provided to parents.

Hepatitis B is a potentially life-threatening liver infection. The virus can cause chronic liver disease and chronic infection, and increases the risk of death from cirrhosis of the liver and liver cancer.

China reported the cases to the WHO on Friday.