However, they have suggested it is unlikely to be on the scale of an epidemic.

The World Health Organization declared that the Sars outbreak had come to an end earlier this month.

The highly contagious virus had spread across the globe killing over 800 people and infecting over 8,000 since it first emerged late last year.

However, scientists have always insisted that it could reappear again particularly during the flu season, which starts in autumn.

Expert view

Editors at the Journal of Epidemiology and Community Health asked nine international experts for their views.

It is possible that further cases of Sars will reoccur later this year   Martyn Regan, UK's Health Protection Agency

Two said they did not believe the virus will reappear. Four said they were uncertain and three predicted it would.

However, they all agreed that public health officials must not let their guard down.

They said one of the risk factors was that the source of Sars is still not known.

It has been suggested that the virus crossed the species barrier from animals to humans.

Some scientists believe the source may be civet cats and "racoon dogs" in China.

The international experts said effective isolation procedures will be the best way of stopping the virus from taking hold.

Dr Abu Abdullah, an assistant professor in the University of Hong Kong, said: "In the absence of any effective vaccine or treatment, the only way to combat Sars is to limit its spread."

Dr Rashid Chotani, director of the Johns Hopkins Bloomberg School of Public Health, also called for steps to be taken in case of another outbreak.

"It remains to be seen if Sars will re-emerge in the winter of 2003 but it is better to be proactive rather than reactive for preparing for this possible pandemic as such measures can save thousands of lives as well as an enormous global economic burden," he said.

Martyn Regan of the UK's Health Protection Agency added: "It is possible that further cases of Sars will reoccur later this year riding on the tide of other seasonal respiratory viruses.

"How the next chapter on Sars will unfold will depend on effective targeting of enhanced surveillance programmes and rapid isolation of hospitalised cases."

The first known case of Sars was discovered in Guangdong province, in China, last November.

By February, the Chinese Ministry of Health had reported 300 cases including five deaths in Guangdong province.