London - The World Health Organisation (WHO) has established a network of collaborating centres around the world to help combat the influenza virus.
The centres will be responsible for collecting blood samples from flu victims and looking out for new types of the virus that may risk creating a pandemic.
The first step towards the production of a pandemic vaccine starts when a centre detects an influenza virus strain that differs significantly from those in circulation. The information is then communicated to the WHO.
At the same time, the centres are involved in the constant checking of viral mutations to ensure that the vaccines being prepared for seasonal flu are correctly targeted against the genetic changes to the virus's proteins.
These new types of flu viruses are then used to make vaccines, which are designed to stimulate the immune system to recognise and attack the haemagglutinin protein of the virus. The manufacturing process, which involves growing the flu viruses in hens' eggs, takes several months.
The Independent