Neurologist Raymond Cheung at the University of Hong Kong said rare complications do happen with any kind of vaccination, but Jiayi's case might not be all that clear.

"Some people may have very poor immunity or genetic problems ... and on rare occasions, (vaccines containing live) attenuated virus may cause an actual infection," he said.

"But it's hard to say if the girl suffered from such a complication. Especially in rural parts of China, there are (reports of) very bad, contaminated vaccines."

Liang knows of at least six other children in Jiangmen who were left paralyzed after such vaccinations and he cycled 6,000 km (4,000 miles) from his home to Beijing in May 2004 to plead for help.

"I filled out many forms but there has been no reply even though they promised me one in two months. An official said it was my bad luck and that this is my destiny," said Liang.

Asked about these cases in Jiangmen, there was no immediate response from China's Health Ministry.

BAD CHINESE DRUGS

Fake or bad drugs have killed dozens of people in China in recent years and raised questions about drug safety.

Public fears grew in 2004 after China revealed that at least 13 babies had died of malnutrition in the eastern province of Anhui after being fed fake baby milk with no nutritional value.

This month, China fined Qiqihar No. 2 Pharmaceutical Co. Ltd. and revoked its license after its drug meant to treat gastric disorders killed 11 people and turned out to be bogus.

The scourge of fake drugs goes far beyond the borders of China. Health experts say fake China-made malaria drugs are flooding Indochina where they have killed mainly poor people, who have no choice but opt for cheaper versions of the medicine.

Back in China, distraught father Yu Tongan is clamoring for justice. Yu's 12-year-old son ran a very high fever, fell into a coma and became paralyzed after being vaccinated in 2005 against encephalitis at his school, also in Jiangmen.

Yu has tried to seek help from all levels of government in Guangdong, only to be rebuffed each time.

"They told me my plight was not bad enough ... maybe it's because my child has not died yet," Yu told Reuters.

"I am sure the vaccine had problems or was spoilt. They should address our problem and find out what happened. This should not happen to other children."

That would probably be the best outcome that parents of these children can hope for.

"For encephalitis, there is no cure. You can't control or reverse the damage ... and several years down the road, damage would have been done. I think the girl (Jiayi) would be in a persistent vegetative state," neurologist Cheung said.

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