HONG KONG, July 27 (Reuters) - China should have investigated why some children suffered severe brain damage after being vaccinated against Japanese encephalitis a few years ago, a World Health Organisation official said on Friday.
While rare severe adverse reactions are known to occur with any kind of vaccine, such mishaps must be closely examined to ensure the safety of vaccines, said Stephen Hadler, WHO’s medical officer in China.
"These cases should have been investigated to determine which vaccine was used, and information collected about clinical illness, timing following vaccination, other medical conditions, etc.," Hadler said in an e-mail reply to Reuters from Beijing.
"That would help determine whether these adverse events could have resulted from vaccine itself, from handling of the vaccine, were due to another underlying medical condition, or were coincidental."
WHO was unaware whether such an investigation had been carried out, he said.
His comments came as three children who suffered severe brain damage after being vaccinated against Japanese encephalitis in 2003 and 2005 had their case heard in a Chinese court in southern Guangdong province this week.
Ordinary citizens suing powerful state companies are rare in China and this case is especially sensitive as it calls into question the standards of Chinese medicines at a time of mounting safety concerns following a string of scandals.
The children developed a very high fever hours after being injected. One fell into a coma and became paralysed when she regained consciousness. She has since remained in a vegetative state. The other two children only regained their ability to walk recently but are mentally retarded.
China manufactures and uses two types of Japanese encephalitis vaccines — killed vaccine made in cell culture and live attenuated vaccine, the WHO said.
"The live attenuated vaccine has been used extensively within China and outside China (including South Korea, India, Nepal), through licensing for use in the recipient country. This vaccine has not been associated with serious brain damage," the WHO said.
Passed by mosquitoes, Japanese encephalitis can result in paralysis, seizures, coma and death. It is endemic in most parts of Asia, while China, India, South Korea, Japan, Taiwan and Thailand control the disease with vaccines.