In Reply We read with great interest the correspondence from Dr Meirson and colleagues, Dr Patel and colleagues, and Dr Rickard and colleagues in response to our original investigation on replacement of peripheral intravenous catheters (PVCs).1 Dr Meirson and colleagues correctly point out that the number needed to harm was very high. We discussed this point in the article and whether an incidence increase of 1 PVC-associated bloodstream infection (BSI) per 10 000 days of PVC use (or of 0.77 PVC-BSI per 2732 PVCs placed) justifies routine replacement. From an ecologic perspective, approximately 1.2 billion PVCs are placed or replaced annually; thus, even though the outcome is rare, a large number of patients contract a PVC-BSI per year in the world. Moreover, during the intervention period we detected a high proportion of Staphylococcus aureus PVC-BSIs, which is associated with high mortality. Interestingly, a recent study reported that infections caused by S aureus and gram-negative bacilli were more frequently detected in PVC-BSIs compared with central venous catheter-related BSIs.2