One is that we need to recognise that there is no such thing as a purely national health crisis. We are all in this together. The technology and infrastructure that have smoothed the progress of globalisation, such as airline travel and international communications, are also potential carriers of health risks. With the potential for rapid spread of a disease, a national health-care crisis can quickly become a global health crisis.

The lessons are fairly clear. We do not need the kind of beggar-thyself policies that naively try to isolate countries from the damaging fallout, such as placing draconian restrictions on travellers from certain regions. Instead, what the crisis teaches us is the urgent need for effective co-operation between regulatory authorities, domestic and international.

There are signs that this is already happening, such as the unprecedented co-operation among various laboratories in identifying and isolating the virus. But much more needs to be done, especially at the regional level, to develop broad structures and regulatory networks of co-operation. They would enable early identification, information-sharing and the development of regulatory standards. All of this is easier said than done.

A sceptic could justifiably point out that since co-operation between Guangdong and Hong Kong has been so deficient, how likely is a regional response? If health crises such as Sars are to be adequately dealt with in future, regional regulatory frameworks must be developed. Two things need to be done to make this happen. First, we need to reconstruct the regulatory capacities of health authorities for warning and control of diseases. Second, these health regulators should be enmeshed within a broader structure of regional co-operation between health authorities.

This will require that domestic regulators take on a quasi-international role that may sit uncomfortably with states across the region, which jealously guard the prerogatives of national governance.

But the experience of Sars (and the Asian economic crisis before it) shows us the crucial influence of globalisation: it lies less in constraints imposed on the capacities and functions of national governance, and more on how it reshapes the architecture of domestic governance.

The point is this: if effective regulatory frameworks are to be developed, officials must understand that regulatory resources - such as expertise, information and finance - are often dispersed across national jurisdictions in a range of governmental and non-governmental organisations. The Sars case shows that information-sharing and transparency between authorities is crucial to regulation. No national agencies can claim to have a monopoly on information. This means national agencies must have global and regional roles.

Sars also teaches us that globalisation is a complex process that often pushes in opposite directions. Economic globalisation tends to weaken public health sectors in both developed and developing countries. But this hollowing-out of the public health sector creates and amplifies the kind of health crisis we confront today. One reason is the decline in resources that national governments have had to fund and finance adequate public health systems.

Indeed, it is fortunate that the Sars crisis has affected two areas - Singapore and Hong Kong - with relatively well-resourced public health systems. Imagine if the epicentre of the crisis were Indonesia, where the public hospital system, especially since the Asian crisis, has rapidly deteriorated. Without a doubt we would be looking at a far more serious situation. Yet, Indonesia reflects the penurious condition of many public health systems around the globe, making them a global recipe for disaster.

Globalisation has also replaced public health systems with unregulated private health markets. Yet, in a crisis we expect the public sector, not markets, to take the lead. Just as the New York Fire Department went into the burning World Trade Centre buildings, it was health workers who walked into the eye of the Sars storm.

Globalisation creates pressures to develop private health-care systems, often at the expense of the 'common' resources needed by the public health sector. That is the paradox: we need these common resources to combat the health crises produced by the deep-seated economic transformations under way in China and other countries. With China's membership in the World Trade Organisation, these tensions will become particularly acute; they may even affect the sustainability of economic reform.

More generally, Sars is a timely reminder to the World Bank - and to other promoters of private health markets - that reforms may erode governments' abilities to deal with the new risks produced by globalisation. This applies not just to public health-care systems, but also to the research skills, capabilities and resources within the public sector which, as we have seen, are vital in dealing with the Sars crisis.

Economists like to talk about externalities - though I much prefer the idea of the 'commons' - and what they call the positive spillover effect of publicly provided services like hospitals and research institutions. But the process of globalisation and the pressures it creates may well lead to myopic policies that erode common public resources such as the public health system. And that, in turn, may well undercut the sustainability of globalisation.

Kanishka Jayasuriya is associate professor in the Department of Politics and Public Administration at the City University of Hong Kong