Face masks are a cheap, effective public health "frontline" against epidemics such as swine flu, especially when vaccines are unavailable or in short supply, UNSW infectious disease expert Professor Raina MacIntyre says.

Professor MacIntyre, who sits on a national panel advising on influenza and emerging infectious diseases, led national commentary by a number of UNSW experts on the latest influenza outbreak, which threatens to become a pandemic.

If a pandemic occurred, face masks would become an important protective measure until a vaccination was developed, Professor MacIntyre, from the School of Public Health and Community Medicine, said.

A world-first clinical study of virus transmission in Sydney families led by Professor MacIntyre found those wearing a mask were four times less likely to be infected than non-wearers.

Both surgical masks and the more fitted P2 masks were equally effective if worn correctly, the research published in Emerging Infectious Diseases, the journal of the US Centres for Disease Control, showed.

School of Medical Sciences virologist Professor Bill Rawlinson explained the origins and epidemiology of swine flu, telling Sky News he doubts the seasonal influenza vaccine would provide protection against the current threat.

But he said people should go ahead with immunisation to avoid catching flu, which could weaken them and make them more prone to a swine flu attack.

On the economic impacts of a potential pandemic, Professor Fariboz Moshirian, from the Australian School of Business, told the Australian Financial Review the spread of the disease would damage the global aviation industry and market sentiment.

Swine flu will be among topics discussed tomorrow (Friday 1 May) at UNSW's inaugural Advances in Public Health and Health Services Research Symposium, a showcase of the University's groundbreaking population health research.

For regular updates and further information about the swine flu situation visit the NSW Health website

Anyone planning international travel should visit the Department of Foreign Affairs and Trade website for updated advice.

Contact: Steve Offner | 02 9385 8107 | s.offner@unsw.edu.au