Daniel Chiu said half the cases can also cause mental retardation and hearing loss.

A vaccine for infants is available overseas but will only be on the market in Hong Kong after the second half of this year, Chiu said.

Emphasizing that the delay was ``unrelated to our government,'' Chiu cited ``a foreign administrative hiccup'' as the reason.

According to a January 5 drug shortage bulletin on the American Society of Health System Pharmacists Web site, the vaccine, pneumococcal conjugate 7-valent, or Prevnar, has been in short supply since February 2004 because Prevnar's manufacturer, Wyeth ``has implemented changes to the company's quality assurance processes.''

``The vaccine was developed and marketed in February 2000. It is included in the immunization programs in the United States, Canada, Australia, Finland and some European countries,'' Chiu said.

Chiu, who is also the central coordinator of the Medical Association community network, said streptococcus pneumoniae - the leading cause of bacterial meningitis in children - is most dangerous to children aged six and under as well as the elderly with weak immunity.

It is also a common cause of pneumonia, bacteraemia (bacterial infection of blood) and otitis media (mid-ear inflammation).

``The bacteria is common and can be everywhere, especially in winter and spring,'' Chiu said. ``It can be spread between humans through droplets and will survive in the mucus of the nose.''

A Hong Kong University study in 2000 found that 383 of the 1,978 children aged two to six in 79 day-care centers were carrying the bacteria.

``Hong Kong's meningococcal disease cases range from two to 10 each year, which made it hard to study the trend,'' he said.

``But the potential problem cannot be ignored because the currently available vaccine in Hong Kong can only protect children aged two and up making infants from six months to two-years-old vulnerable.''

The five antibiotics currently used in Hong Kong against the bacteria have seen an increasing resistance rate of up to around 70 percent, he added.

Chiu said Prevnar will provide 90 percent protection against the bacteria.

``Although the price has not been set, I will recommend that parents vaccinate their infants when the vaccine is available [later this year],'' Chiu said.

matthew.lee@singtaonewscorp.com