The Friday Five covers five stories in health research that you may have missed this week. There are plenty of controversies and troubling ethical issues in science – and we get into many of them in our online magazine – but this news roundup focuses on scientific creativity and progress to give you a therapeutic dose of inspiration headed into the weekend.Covered in this week's Friday Five:- Sex differences in cancer- Promising research on a vaccine for Lyme disease- Using a super material for brain-like devices- Measuring your immunity to Covid- Reducing risk of dementia with leisure activities