The effectiveness of antivirals in treating patients with avian influenza is highly dependent on how early the drugs can be administered following the onset of infection.
This is one of the valuable lessons Ireland and other countries could learn from Vietnam's experience in tackling a serious flu epidemic, according to the director of the National Institute of Hygiene and Epidemiology in Hanoi, Prof Nguyen Tran Hien.
In an address to staff at the National Virus Reference Laboratory (NVRL) in University College Dublin, Prof Hien said early treatment with antivirals such as Tamiflu significantly reduced mortality from the H5N1 virus.
"Unfortunately, by the time many of our patients were diagnosed and transferred from rural clinics to hospitals in the cities for treatment, they had already developed symptoms of advanced viral pneumonia," he said
The epidemiological evidence showed that the time from last presumed contact with infected poultry to the onset of illness or symptoms was usually three to five days but in some cases could be as long as 15 days, he said.
While there have been no documented cases of human-to-human transmission of the H5N1 strain in Vietnam, Prof Hien said they had identified "family clusters" indicating a possible genetic component in the spread of virus.
Vietnam has been the worst-affected of the Asian countries by the virus, recording 100 cases of the H5N1 strain and 46 deaths since the first wave of the epidemic in 2003.
But after four separate outbreaks in as many years, the virus has been largely brought under control by mass vaccinations and the culling of tens of millions of poultry in tandem with a public education programme.
The NVRL has recently forged a partnership with the National Institute of Hygiene and Epidemiology in Hanoi known as the Ireland Vietnam Blood-Borne Virus Initiative.
This partnership plans to build and develop a disease surveillance centre in Vietnam modelled on the laboratory in UCD.
