What do research biobanks, Twitter and the NHS have in common? All involve people who are showing solidarity with others. And thinking about how solidarity plays a role in our society can offer solutions to policy making, concludes a new report published today. For example, Twitter and other social media could be used more systematically to track the spread of disease and share information during flu pandemics. And participation agreements for research biobanks should be revised to make biobanks more efficient in working towards improving health.