In some people there have been concerns about bone density and the risk of fracture when taking PrEP. This is actually an extremely rare side effect. What we can say is if you have patients with pre-existing bone density issues or they are at high risk of osteopetrosis, it is worthwhile to consider a bone density scan before they start PrEP. Remember there are a number of different ways that we can help optimise bone density in our patients. This includes regular calcium rich foods, weightbearing exercise, regular access to the sun, as well as checking your vitamin D levels and supplementation, if their vitamin D levels are low.