The government's surveillance system for infectious diseases has come under fire, with some doctors complaining the network of participating practices is too small and that collection of patient samples for laboratory testing is unreliable.
Some 40 private clinics, 67 government clinics and all public hospitals participate in the Centre for Health Protection's sentinal network, to provide warning of sudden changes in infection rates, by sending samples from patients, such as throat swabs, for laboratory testing.
The centre monitors infection rates of four illness categories - influenza, hand, foot and mouth disease, acute conjunctivitis and acute diarrhoeal diseases - and tests an average of 1,500 samples a month.
But the operator of a private clinic in Wong Tai Sin said none of its samples had been picked up for more than two weeks because a messenger had left his job, and that such a failure meant the centre's information was lacking and so its surveillance was faulty.
A nurse at Dr Choi Kin's clinic, Winnie Chow Mei-ying, said only one messenger, an employee of the Wang Tau Hom Jockey Club General Outpatient Clinic, was assigned to serve the Wong Tai Sin area.
'If the messenger falls ill, goes on a long holiday or resigns, no substitute is arranged from another district,' she said.
The Centre for Health Protection had told Choi the messenger's job would be outsourced, but Chow said this had not happened.
Choi, a former president of the Medical Association, said his practice would not take any samples from patients if no one was collecting them.
'The purpose of the programme has been defeated,' he said. 'It will certainly affect the accuracy of surveillance. If no samples are taken in a particular district, the data will not be comprehensive.'
Choi said his other practice, in Diamond Hill, had not experienced a similar problem because the messenger job there was outsourced, whereas the one in Wong Tai Sin was carried out by a civil servant. 'Outsourced workers are paid per job. Of course they will be more motivated,' he said.
An Aberdeen doctor who participates in the sentinal network, Amy Chan Kit-ling, whose nurse delivers her samples to the Aberdeen General Outpatient Clinic next door, said the low number of participants in the network affected the accuracy of the surveillance exercise.
'I am the only participating doctor in the entire South District. There is only one clinic in the Western District too,' she said. It was 'statistically not viable' to have samples taken from only 1 per cent of all private clinics in the city, she said. 'If so many doctors are not in the scheme, how can surveillance be done properly?'
A spokesman for the Centre for Health Protection said the Wang Tau Hom Jockey Club clinic was run by the Hospital Authority and the centre was following up on why it had sent no one to collect samples.
He said the department also collected samples from sources other than private practitioners, such as from public clinics and hospitals.
An authority spokesman said that if a sample had been taken by a doctor, a messenger would be sent no matter how tight the staff situation.
Centre controller Dr Thomas Tsang Ho-fai said earlier that the centre would expand the network by recruiting 30 more doctors.
The Centre for Health Protection monitors infection rates
The number of doctors it plans to add to its surveillance network: 30