WUHAN, Dec. 25 -- Doctors have ruled out vaccination as the cause of the death of a one-month-old infant in central China's Hubei Province, local authorities said on Wednesday.

The baby died on Dec. 20 in Ezhou City, one day after receiving a hepatitis B vaccination manufactured by Beijing Tiantan Biological Products Co. Ltd., a major supplier of free hepatitis B vaccine.

Her parents found her with a nosebleed early in the morning, and she died at 8 a.m. after after emergency treatment.

According to the diagnosis, the baby died of pneumorrhagia which can be caused by lack of Vitamin K, pulmonary infection and pulmonary vascular malformation.

There have been no effects on other infants vaccinated from the same batch.

To date, eight infants have died following hepatitis B vaccination since November, including four in south China's Guangdong Province, two in central China's Hunan Province and two in Sichuan Province, according to Chinese health authorities.

The one in Sichuan Province involves a vaccine produced by Beijing Tiantan Biological Products Co. Ltd..