Hong Kong will launch Influenza A/H1N1 shot program on Dec. 21, a Hong Kong health official said Monday.

People from five groups should get the flu vaccinations when the Government subsidy program launches Dec. 21, said Gabriel Leung, under secretary for Food and Health of the Hong Kong Special Administrative Region government.

The two million people in the five target groups are chronic patients and pregnant women, children aged six months to six years, seniors aged 65 and above, healthcare workers, and workers in the pig trade.

Leung said that priority will be given to these groups to receive the first batch of 500,000 doses.

"Human swine flu cases continue to be found all over the world and the situation in Hong Kong may become more serious with the arrival of the winter influenza peak. People belonging to the target groups are urged to be vaccinated to reduce the chance of infection and safeguard their health," he said.

Although there are reports of people feeling unwell after the flu vaccination, abnormality has so far not been found, he said, noting that receiving the vaccination is still safe and the public should not be over-worried.

Public hospitals, clinics and medical centers will provide free vaccinations to the target groups, he said.