Polio fight stays despite all-clear

PUBLISHED : Monday, 20 November, 2000, 12:00am
UPDATED : Monday, 20 November, 2000, 12:00am

The local polio immunisation programme, in place since 1963, will continue until at least 2005, when the virus is targeted to be eradicated worldwide, Hong Kong's top expert on the disease said.

A landmark meeting in Kyoto, Japan, on October 29 declared Hong Kong and the mainland, together with 35 countries and areas in the Western Pacific Region, polio-free.

But Professor Leung Nai-kong stressed the need for vigilance against a resurgence of the disease. Professor Leung, chairman of Hong Kong's National Committee for Certification of Wild Poliovirus Eradication, who presented the Hong Kong report in Japan, said until the global target was met, and because of possible imported cases, SAR babies would continue to be immunised with the oral polio vaccine.

Polio is a debilitating viral infection that has been responsible for major fatal outbreaks as recently as 1989 and 1990 in China.

'We have so many travellers to Hong Kong. Our local residents go to other places; we also have residents coming from endemic places, like India, Nepal and Africa,' Professor Leung said.

He said he was not convinced the vaccine posed such a risk that the territory should shift to the alternative vaccine used in the United States. 'Side effects can happen in whatever vaccine. The risk is there, but very small compared to other vaccines. I would not advise children not to receive oral polio vaccine,' Professor Leung said.

The last case of wild polio - polio not linked to vaccines - in Hong Kong was in 1983, but there were two vaccine-related polio cases in 1985 and 1995, the second being fatal.

The second case also sparked some controversy as it was not until September this year that it was reported to Professor Leung's committee, according to a Department of Health spokesman.

A six-month-old boy was admitted to the Prince of Wales Hospital on August 30, 1995, and died less than two months later from respiratory failure. The polio virus was later confirmed to be the vaccine strain Sabin type 1, associated with the oral vaccine. The case was published in the British medical journal Lancet on November 29, 1997.

But Professor Leung downplayed the late reporting of the polio case, adding that vaccine-associated polio cases would not affect Hong Kong's status because only indigenous 'wild polio' cases counted. He was quick to add, however, that his committee took vaccine-related polio seriously.

Professor Fok Tai-fai, chairman of the Chinese University's department of paediatrics and co-author of the Lancet article, said the Department of Health was aware of the 1995 case despite the late reporting because it received samples from his team. The incident sent a message to doctors about the risk of 'vaccinating children with impaired self-defence mechanisms', and that the children might be better off getting the alternative vaccine, Professor Fok said.