At the top of its product information sheet, Schering announces that 'alfa interferons, including PEG-Intron, cause or aggravate fatal or life-threatening neuropsychiatric, autoimmune, ischemic and infectious disorders'.

Specifically, this includes suicide, depression (in nearly a third of patients), aggressive behaviour, hallucinations, bipolar disorders and mania.

Otherwise, the drug may lead to a severe decrease in white blood cells and blood platelets, and may cause diabetes, low blood pressure, irregular heartbeats, angina and even a heart attack. Then there’s pneumonia and respiratory failure, colitis, pancreatitis, autoimmune disorders, loss of vision and retinopathy. And that’s just the one drug.

As for ribavirin (Rebetol is a Schering product), this can cause birth defects or death of an unborn child if you take it when pregnant. Some 10 per cent of those taking ribavirin develop haemolytic anaemia. In combination with PEG-Intron, it can cause blood, endocrine and liver abnormalities.

On its website FAQs For Patients, Schering cheerily notes: 'Certain symptoms like severe stomach pain may mean that your internal organs are being damaged.'

All this and very little assurance that it works. According to Schering, only 24 per cent of patients respond to PEG-Intron, and far less if you are a particular viral genotype.