A pandemic problem with public transport.

TO THE EDITOR: The increasing overcrowding on public transport, particularly trains, in many Australian cities makes for considerable discomfort. As the problem deteriorates, concerns about attributable illness and even death have been raised. 1 Overcrowding on public transport also contributes to the spread of respiratory diseases such as influenza (pandemic or otherwise). 2 The risk of contracting influenza is greatest for people who are within 1 m of an infectious person, through exposure to respiratory droplets, particularly for periods of more than 15 minutes. 3,4 Seasonal influenza , which infects millions of Australians annually — resulting in an estimated 2000 deaths and 10 000 hospitalisations 5 — is a major health concern. As a resident of Melbourne and regular train commuter, personal observation supports recent claims of severe overcrowding, 1 with the average number of people sitting or standing within 1 m of another person on Melbourne trains during peak periods having increased markedly over the past few years. If an average peak commuter is now placed within 1 m of 10 people for a prolonged period twice a day (a conservative estimate), at least 100 infectious influenza contacts potentially occur each week. With annual attack rates for seasonal influenza of 5%–10%, 5 the likelihood of contracting