The rapid spread of the swine flu pandemic has forced the WHO to change strategy and place the emphasis on quick response to severe outbreaks to minimise impact, rather than on attempting to halt the spread of the virus.

The WHO says producing lists of laboratory-confirmed cases of swine flu has become a waste of resources and WHO is not advocating a uniform global plan, but says each country should tailor its response to its own particular situation.

The United States has experienced the greatest number of reported cases, at 40,000, and the greatest number of deaths, at 263, prompting the U.S. government to declare a public health emergency - health officials there believe there may have been more than a million cases, but say the overall influenza activity is abating.

In Australia the swine flu outbreak is stretching the health system with more than 14,000 cases and almost 40 deaths and pregnant women and indigenous people appear to be particularly vulnerable.

Health experts continue to emphasise that good hygiene can help prevent infection with swine flu and regular washing of hands, covering the nose and mouth when sneezing or coughing and discarding used tissues immediately, will all offer some protection.