We have been two years in the pandemic, and many interesting patterns have emerged that are worth discussing. I can only attempt to touch on a few of them, which are related to the practices and flows of health data. It was interesting to see, as the pandemic ensued, how lots of different kinds of data were mobilised. And lots of different social actors got involved in the use of data, for many different purposes. Data were put in circulation in ways and speed that were unforeseen, from both public and private sector companies. But data circulate well in some directions, and less so in others. Overwhelmed perusing a constantly moving panoply of numbers, charts and assessments on the state of the pandemic, it is easy to miss out that some data are not flowing well at all, and that others should perhaps stay where they are.