The Sars outbreak in 2003 left question marks over the responses and judgment of Hong Kong and world health authorities. This city learned painful lessons from failure to heed early warnings of a deadly, highly contagious virus, or to take effective steps to stop it spreading from hospitals to the community, or promptly quarantine infected buildings. Paradoxically, the World Health Organisation faced criticism for imposing commercially damaging travel advisories without much information about the disease, even though there is no question public health comes before business or the economy.

The failings were much on the minds of Hong Kong officials when swine flu emerged in April 2009. As a result, they have been accused of over-reacting with draconian measures against what has since become another seasonal flu. But had it been as severe as feared at first, it would have been a different story.

The same questions would have been on the mind of WHO chief Dr Margaret Chan Fung Fu-chun, Hong Kong's director of health during Sars. It is therefore surprising that the organisation's response to swine flu on her watch should have attracted damning criticism from a panel of experts appointed to review it. They said the WHO failed to issue timely guidance, with poor communications sewing confusion about the most basic definition of a pandemic. Worse still, the lack of transparent procedures for managing conflicts of interest among expert advisers contributed to suspicions about the organisation's interests. The communications bungle in particular is disappointing, given that the hysteria and global ostracism sparked by Sars might have been avoided if the WHO and officials - including Chan - had handled public education about the disease more deftly.