Health authorities in Northwest China's Gansu Province said late Friday that they are investigating a new infant death linked to hepatitis B vaccination, the 11th such case in the country since November.

A baby in the provincial capital of Lanzhou died after receiving the vaccination manufactured by the Dalian Hissen Bio-Pharm Inc., a major supplier of free hepatitis B vaccine, the Gansu Provincial Health and Family Planning Committee said in a statement.

The infant's body had been buried, but doctors said they cannot rule out vaccination as the cause of the infant's death.

Further investigation is under way.

Also Friday, health authorities in east China's Yongjia County, Zhejiang Province reported that a two-month-old boy died one day after receiving a hepatitis B shot on Dec. 20. The vaccine was also produced by the Dalian Hissen Bio-Pharm Inc.

The parents of the boy are from central China's Hubei Province. They had a fight after the baby's death and buried the boy without reporting the case, according to an initial investigation.

The parents agreed on an autopsy of the boy on Friday. The result will out after a month, according to authorities.

Previously, nine infants have died following hepatitis B vaccination since November, including four in south China's Guangdong Province, three in central Hunan Province, and two in southwestern Sichuan Province.

Of the nine fatalities, the majority came after use of vaccines made by BioKangtai from Shenzhen, Guangdong. Two of them died after receiving vaccines from the Beijing Tiantan Biological Products Co., Ltd.