A new vaccine is now available in countries all over Asia to prevent infants from contracting rotavirus gastroenteritis, an illness that strikes without warning and can sometimes be fatal.

The rotavirus vaccine provides 85 to 100 per cent protection against the disease, which almost all children suffer from at least once by the time they are five, according to experts who attended the 11th Asian Conference on Diarrhoea Diseases and Nutrition in Bangkok last month. The vaccine also helps reduce the time a child may have to spend in hospital if he or she is infected.

"This new vaccine has been found to be effective in protecting infants against severe rotavirus gastroenteritis and its safety profile has been confirmed," says Professor Timo Vesikari from the University of Tampere Medical School in Finland, who was the lead researcher on trials for the vaccine.

It's young children who are most susceptible to rotavirus infections. Those infected usually run a high temperature, throw up all that they eat and suffer from diarrhoea. In severe cases, rotavirus gastroenteritis can lead to dehydration and require hospitalisation.

The illness usually lasts from three to nine days, but can sometimes make the patient suffer for up to three weeks. The availability of the new vaccine should also reduce the total cost of infant health care in the Asia Pacific, the doctors say.

The rotavirus vaccine works by stimulating the body to mimic the immune response to natural rotavirus infection, which protects the infant from subsequent attacks.

"The availability of the new rotavirus vaccine in Asia is a breakthrough. Vaccination is the most effective way to prevent rotavirus gastroenteritis, which is highly infectious," says Dr Hans Bock, vice president of clinical R&D and medical affairs at GlaxoSmithKline Biologicals.

The rotavirus, which is transmitted mainly by the faecal-oral route, can live on an object for days. Transmission can also occur from person to person, ingestion of contaminated water or food and contact with contaminated surfaces. In developed countries, 27 per cent of all hospitalised rotavirus cases are acquired in hospitals. In developing countries, the corresponding figure is 32 per cent.

In temperate Asian countries such as China, Hong Kong and Taiwan, the peak season for rotavirus infections is from December to March. In tropical places like Malaysia, Thailand and Vietnam, there is no obvious season the virus favours.

The incidence of infections is pretty much the same among children in developed and developing countries. Nearly every child has at least one episode of rotavirus diarrhoea by the time he or she is five. Official statistics indicate that one in five will visit a clinic, one in 65 will be hospitalised and one in 293 will die.

Every year, the rotavirus causes about 125 million episodes of gastroenteritis, resulting in about 440,000 deaths around the world. The majority of deaths occur in the Indian subcontinent, sub-Saharan Africa and South America.

In the absence of a rotavirus vaccination programme it is estimated that 171,000 of children in Asia today will die of rotavirus diarrhoea, 1.9 million will be hospitalised and 13.5 million will require an outpatient visit by the time they reach their fifth birthday.

There is no specific treatment for a rotavirus infection. What doctors do are take measures to relieve the symptoms by administering oral or intravenous fluids to prevent dehydration and prescribing drugs to manage the fever.

Improved general hygiene and sanitation standards do not effectively reduce the incidence of rotavirus infections. However, the new vaccine offers the best protection for infants and its development fulfils the goal the World Health Organisation had identified as a top public health priority.