The Chinese government this week announced it would launch the world’s first mass vaccination programme for the flu in October amid fears that China could soon face a mass outbreak of the A(H1N1) flu.

But experts fear the inoculation programme, which will only reach about 5 per cent of the 1.3 billion population, might be far from sufficient in light of the scale of the outbreak many expect here.

More than 100 new A(H1N1) cases were reported last weekend, mainly among returning school students. China has so far reported 5,592 cases, and health officials said on Tuesday they expect the number of cases “to soon double to 10,000.” There have so far been no reported deaths in China, but 12 people have died in Hong Kong.

The government this week ordered the release of a home-grown A(H1N1) vaccine, the world’s first, which was approved on September 4.

Its producer, Sinovac, said the vaccine would be effective after only one dose. Health Minister Chen Zhu said inoculations would begin in October and would target 65 million people by the end of the year, or 5 per cent of the population.

“Realistically, the supply, five per cent or otherwise, will not be able to match the demand in initial months,” Vivien Tan of the World Health Organisation told the China Daily newspaper. “There is a need to identity priority groups for vaccination.”

Mr. Chen said the inoculation would begin with schoolchildren, people with chronic respiratory diseases and pregnants. Officials say the highest-risk group is schoolchildren, with millions returning to schools in coming weeks. Almost all the 100 new cases were reported from schools and more than 20 schools in several provinces have been closed this week.

With the onset of the winter season in October, coupled with the annual migration of millions of farmers back to their home towns for harvests, health authorities fear the flu, which has so far been largely restricted to larger cities, may now also spread to rural areas. The Xinjiang region, in China’s far west, reported its first A(H1N1) case this week, a middle-school student.