Nine people have died of flu since January 24 and the peak infection period is likely to last until around the end of next month.

But the number of people getting flu prevention jabs remains low.

The head of the Centre for Health Protection, Dr Thomas Tsang Ho-fai, said the seasonal flu vaccination rate in Hong Kong was low compared with developed countries.

Tsang said that while more than half the population of the United States received flu vaccinations, a maximum of one in seven people in Hong Kong was vaccinated.

The local figure is based on the annual one million doses of flu vaccine imported into the city. It is not known how many of those doses have not been used.

Since November, only about 360,000 people received either free or government-subsidised flu jabs, a 25 per cent decline from last year.

The centre's swine flu vaccination programme last year drew a dismal 9 per cent participation rate.

Health officials rely mainly on television advertisements or posters to encourage people to take the jabs, a method it has been using for years.

'The US has a much longer history of flu vaccination,' Tsang said. 'In Hong Kong, the flu vaccination has been getting more popular in the past decade.

'But the vaccination rate in Hong Kong is rather low because many people still worry about possible side effects. We welcome suggestions and comments on how we can do better.'

Since November 1, the government has provided free seasonal flu vaccines to several high-risk groups such as the elderly living in homes for the aged and health care workers. Children under six and people aged 65 or above can receive government subsidies of HK$80 and HK$130 respectively to get the shots at private clinics.

The prevailing influenza viruses in Hong Kong include influenza A(H3N2), influenza A(H1N1) 2009 (swine flu) and influenza B.

This year's seasonal flu jabs also cover swine flu.

Cheung Tak-hai, the vice-chairman of the Alliance for Patients' Mutual Help Organisations, said possible side effects of swine flu vaccines scared off many chronically ill patients to get the shots.

Several recipients of swine flu vaccines last year were reported to have developed Guillain-Barre syndrome, an acute disorder in which the body damages its own nerve cells, resulting in muscle weakness and sometimes paralysis.

As the seasonal flu vaccines used this year also cover swine flu, the shadow of Guillain-Barre syndrome still lingers in people's mind, Cheung said.

Dr Ho Pak-leung, a microbiologist at the University of Hong Kong, said the promotion of flu vaccinations in the city was a failure.

'What we have seen in the media so far is just one or two senior officials asking people to take the vaccines, or in some television ads,' Ho said. 'Such publicity drives are very outdated. Hong Kong needs a rethink of its flu strategies.'

More proactive arrangements, Ho says, could include holding citywide vaccination days, sending injection teams to schools and organisations, and setting a clear target for the immunisation rate.

'Such health targets are commonly adopted overseas as a public health policy. After such targets are set, the government would have a bigger drive to meet the goal.'

Ho said it was also disappointing that the Centre for Health Protection could not even obtain key statistics, such as the actual vaccination rate for the whole population or infection rate in various target groups such as the elderly.

The president of the Medical Association, Dr Choi Kin, said the centre - established in 2004 after the outbreak of severe acute respiratory syndrome in the previous year - fell short of public expectations.

'The flu vaccination strategy has been wrong,' he said. 'For example, the centre only subsidises young children and the elderly for flu vaccinations in the private sector.

'It sends the wrong message to other age groups that they are not susceptible to the flu risk. It is obviously wrong because many young people have no immunity against swine flu.

'Some patients with severe complications are young people with no underlying diseases,' Choi said.

Hong Kong should have a universal flu vaccination programme to reduce deaths and severe cases, he said.

The government this year bought 300,000 doses of vaccine for its free immunisation programme at a cost of HK$8.67 million, with each dose costing around HK$29.

It is estimated that free vaccinations for the city's population of seven million would cost about HK$203 million. Some of the 380,000 young children under six may need two doses.

The cost would be about HK$37 million if the programme covered only 890,000 people aged 65 and over and 380,000 children aged six months to six years.

Tsang said whether Hong Kong should have a universal vaccination programme was a policy decision outside the centre's authority.

'We don't know how many more people will take the shots if they are free,' he said.

A survey by the centre of 1,000 people who did not have the swine flu shot last year showed that fewer than 5 per cent of respondents did not do so because of the cost.

Fear of the jab

More than 50 per cent of people in the United States get the flu shot

The vaccination rate in Hong Kong is only about: 14%