Forty-four out of 84 students have been hospitalized after they were given a Hepatitis B vaccine Thursday in south China's Guangdong Province, head of local disease prevention and control center said Friday.

The 44 students developed symptoms of a reaction , including vomiting, stomach aches and dizziness after being given the vaccine at primary school in Huilai County in Jieyang City, said Wu Junqiu, head of the disease prevention and control center of Huilai.

Among them, 39 have already got better and only had slight stomach pains now, the other five students throats were inflamed, Wu said.

The patch of HB vaccine used numbered 110,000 doses. Of which, more than 90,000 doses had been administered but no other cases of abnormal reaction had been reported, Wu said.

However, local health authorities have sealed the remaining vaccine, stopping further use, after the students' illnesses.

The provincial disease prevention and control center dispatched experts to Jieyang Thursday to probe into the case.

"The investigation is still under way," Wu said.

The batch of HB vaccine, with a shelf life till Sept.1, 2010, was produced by a company based in Shenzhen city of Guangzhou.