Drug company Roche says the approval follows the results of a study which showed Herceptin reduces the risk of the cancer returning by 46 percent compared to chemotherapy alone.

Herceptin already has approval in the EU for the treatment of advanced HER2-positive breast cancer.

Herceptin works by blocking the HER2 protein produced by a gene with a particularly aggressive cancer-causing potential.

Around a fifth of breast cancers are HER-2 positive.

The new approval of Herceptin means its use can be extended to a large number of mainly younger patients.

Campaigners have been demanding Herceptin to be made available for women with less advanced breast cancer and in the UK the NHS has promised it will fast-track its appraisal of the drug.

Herceptin has been the subject of high profile legal battles by women seeking access to the drug.

A year's course of the drug costs around 20,000 and it has become a 'post code lottery' in the UK with some health authorities supplying it while others have denied it to women, hence the court cases.

Health Secretary Patricia Hewitt intervened in the debate last October saying NHS bodies should not withhold the drug on cost grounds from patients whose doctors had recommended it.

There are some concerns however that Herceptin's effectiveness is over-rated but many women with this type of cancer welcome the news.

The family are known to have slaughtered and cooked a pig and chickens for a feast on April 29, animals which are known to be highly susceptible to the virus and attempts to test local chickens and pigs for the virus have met with fierce resistance from villagers who blame the government for not providing enough help

This most recent cluster has engendered renewed interest in the theory held by many scientists that genetics might predispose certain people to be infected by H5N1, which remains essentially a disease of birds.

Apparently some people who have survived H5N1 have been found to have more of a type of receptor cells along their respiratory tracts that avian flu viruses like to bind to which in theory would explain why some humans might be more susceptible to H5N1.

Such a genetic trait would also explain why cluster cases have invariably involved blood relations, and never husbands and wives.

The WHO says that familial susceptibility amongst certain races, certain cultures and certain groups of people appears to play a role in the pathogenesis and behaviour of the virus when it jumps from one species, like poultry, to humans.