As a way of approaching the multiple ways a pandemic affects urban life, the authors suggest the notion of porosity. Through this, the article revisits the Danish capital during the cholera an typhus attacks, noticing how porosity is mobilized around contagious materials and bodies. Relating this to the COVID-19 outbreak, the article goes on to note how the porosity also can be seen in a temporal sense, stretching out from the fragile present to the promise of a new normality for the city and its metabolism.