By Tan Ee Lyn

HONG KONG, Nov 16 (Reuters) - Paediatricians are urging governments in Asia to bolster national immunisation programmes with vaccines against the rotavirus, the most common cause of severe diarrhoea in young children.

Rotavirus kills about 611,000 children worldwide a year, or a child every minute. Africa and Asia account for 90 percent of these deaths, with more than 180,000 occurring in Asia.

Experts said the high costs of rotavirus vaccines (US$50 for each of 3 doses) should not be an obstacle.

"In Mexico and Chile, they decided it would be cost effective (to have all children vaccinated against rotavirus) and data show a decrease in mortality and morbidity," said Usa Thisyakorn, president of the Paediatric Society in Thailand.

The World Health Organisation said it recommended the inclusion of rotavirus vaccination into national immunisation programmes in places where its efficacy has been proven, but it gave a word of caution.

"To date, the clinical efficacy of rotavirus vaccines has been demonstrated mainly in the United States, Europe and Latin America. Experience with several other oral vaccines has demonstrated that in terms of vaccine safety and efficacy, considerable regional differences may exist," it said.

"Clinical trials are currently ongoing in Africa and Asia, where rotavirus disease burden is very high and where the need for more data on vaccine efficacy is particularly urgent."

The Global Alliance for Vaccine and Immunization (GAVI) has funded the use of rotavirus vaccines in some countries in Europe and Latin America with a gross national income of under US$1,000 per capita.

"To further expand new vaccine use in other countries such as Philippines not currently covered by GAVI, other donors and foundations should also come forward," the WHO said.

GAVI is backed by governments and the private sector.

INFANTS MOST AT RISK

Rotavirus affects nearly all children before they turn 5 and 70 percent are 11 months old or younger. Highly contagious, it can survive in the environment for hours on hands, and for days on solid surfaces. Excreted in stools, it is transmitted orally person-to-person very easily via toys and other objects.

Between 25 percent and 60 percent of diarrhoea patients in Asia who end up in hospital suffer from rotavirus.

Without proper fluid replacement, a child can be dehydrated within 24 hours and develop serious complications such as electrolyte imbalance, organ failure, shock, and even die.

"For an infant, any loss of fluid that is more than 10 percent of body weight is crucial, and at 15 percent it can go into organ failure," said Lulu Bravo, paediatric professor and executive director of the National Institute of Health at the University of the Philippines.

One way to counter diarrhoea is to replace water loss with oral rehydration fluids. But that is difficult because rotavirus causes vomiting, making it difficult for anyone to hold down water, let alone an infant or young child. (Editing by Jeremy Laurence)

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