Yuen Kwok-yung, the chair professor of the University of Hong Kong's Department of Microbiology, first endorsed the use of ribavirin and steroids at a press briefing on March 18 last year, just a week after the Sars outbreak began at Prince of Wales Hospital. Professor Yuen said treatment of Sars - the causative agent of which had not been identified at that time - must be based on 'common sense and logic'. He said that a combination of broad-spectrum ribavirin and steroids led to the recovery of three patients at Kwong Wah Hospital. Recalling last year's chain of events, Professor Yuen said he did not advocate high dosages of steroids. 'I suggested we use ribavirin and for the very serious cases to try moderate-dose steroids, just 1 to 3 grams,' he said, adding that such low doses would not have caused avascular necrosis. 'I just suggested that it should be given to patients who are going into severe respiratory failure. And up until now I have not backed down. If it comes back again, for cases which did not respond to antivirals I am still going to give steroids.' Professor Yuen's advice was also sought by the then-dean of Faculty of Medicine, Sydney Chung Sheung-chee, and the chair of the Department of Medicine and Therapeutics, Professor Joseph Sung Jao-yiu, who also headed Prince of Wales Hospital's equivalent department. On April 19 last year, Professor Sung announced that 95 per cent of 138 patients at Prince of Wales given ribavirin and steroids - in either low or high dosages - had responded to treatment. A slew of articles were published in international journals about the anecdotal success of treating Sars in Hong Kong. By May, Yuji Oba, of the University of Missouri in Kansas City, wrote in the New England Journal of Medicine that early treatment with corticosteroids 'is highly controversial and is not a standard of care, at least in North America'. Professor Sung told the South China Morning Post that pulse injections, or high doses, of steroids were given - up to a maximum of 3 to 5 grams. 'Steroid use was quickly tailed down when the patients' symptoms improved and chest inflammation receded,' he said. The professor also said the 'most important treatment' was supportive therapy including oxygen and ventilatory support. Professor Yuen said with the Amoy Gardens outbreak, doctors began seeing many patients not responding to ribavirin and steroids. 'At that stage, kaletra was added to the regimen,' he said. 'Retrospective analysis of patients given the combination of kaletra and ribavirin showed that the mortality rate was significantly lower.' Professor Sung said that the best results in animal studies came from interferon, a common cancer therapy. The World Health Organisation said the jury was still out on treatment. The body has recommended that an international Sars trials study group be set up to assess the risk benefit of potential therapies and assist in preparing clinical trials ahead of the re-emergence of Sars or other emerging diseases.