Bird Flu outbreaks or pandemic flu?

- Avian Influenza affect primarily birds and not humans Avian Influenza refers to a group of viruses which affect bird species. Rarely, one of these viruses affect human beings. The current H5N1 is also known as the “Avian plague”, having led to cullling of billions of chickens, ducks and geese in South Asia. So far, only 117 people were contaminated by the virus and more than a half died (60 cases). For detailed figures, please refer to the World Health Organisation (WHO) update.

It is important to clearly separate the terms “bird flu outbreaks” and “pandemic influenza”, not to create panic. The main danger nowadays regards food safety and the spread within poultry.

- Why could H5N1 trigger a pandemic in the next few months? H5N1 has never circulated in humans, which means that the human being has no immunity against the virus. Currently, the human cases resulted from a bird-to-human transmission. According to the WHO, it is impossible to state that human-to-human transmission ever took place or not, given the close relations between infected humans and infected chickens in South Asia. This points to the hypothesis that the H5N1 strain does not jump the species barrier so easily. Should the H5N1 strain mutate to evolve in a more contagious form, a new pandemic flu could emerge. The danger of the expanding geographical range of H5N1 is that it increases the opportunities for human infections and thus the opportunity for the virus to gain an ability to be transmitted from human to human.

Anti-virals and vaccines

- What is the effect of antivirals? Should I try and get some antivirals now? Should I take antivirals as a preventative measure? No Like all medicines, Antivirals should be only be used as instructed and provided by healthcare professsionals. During a key window of opportunity, e.g after exposure to the virus and during the early stages of infection, antivirals may reduce the severity and duration of the illness. However, they are not a substitute for vaccination. Neither will they cure persons affected by a pandemic strain, nor can we be sure about their efficacy. They haven’t been tested on a pandemic strain on flu because the pandemic has not occurred yet! The WHO advises that anti-virals should be used under very specific circumstances if a patient has been exposed to the H5N1 virus and if symptoms occur. Consuming antivirals before the appearance of the symptoms may even be counterproductive as the strain may then develop resistance.

- Do we have a vaccine against the pandemic strain? No. Vaccines are produced to counter one specific virus. Therefore, it is not possible to create a vaccine before the emergence of the pandemic strain. Once the pandemic occurs, experts believe it will take at least 6 months to create the vaccine. Once the vaccine has been developed it will take several more months to begin mass-producing the vaccine for use.

Although the pandemic strain will probably be different from the current H5N1, private and public laboratories are trying to create a vaccine against the current H5N1. This is based on the expectation that the difference between H5N1 and pandemic flu will not be major and that an H5N1 vaccine may therefore have a positive effect to boost the immune response.

- Will we have a vaccine at the beginning of the pandemic crisis? No. Supplies are most likely to remain inadequate for many months after the start of the pandemic. At present, the WHO believe that many developing countries will not have access to vaccines during the pandemic time-frame.

The previous pandemics encircled the world in less than 9 months, at a time when most international travel was by ship and therefore very slow. It is expected that the speed and volume of international air travel today will spread the virus over the world in less than 3 months, meaning that a vaccine will be produced very late.

- Will we be protected by the seasonal vaccination? No. Vaccines target one specific strain and are useless when other strains are concerned.

Governments encourage seasonal vaccination for vulnerable populations for two reasons: the first one is to increase the capacities of pharmaceutical industries. The more they sell vaccines, the more capacities they will have to mass-produce quickly the pandemic vaccine. Secondly, they hope that a better coverage of seasonal vaccination may prevent the pandemic virus from spreading too quickly and help the immune system to fight against the disease.

- Will antibiotics be of any help against flu? No. Antibiotics are used to treat infections that are caused by bacteria. They are of no use at all against viruses. Overuse of antibiotics may result in the emergence of drug resistant bacteria and infections that are then very hard to control and treat.

For more information, please visit EPHA sub-section on communicable disease

Last modified on November 29 2005.