Flicking through today´s news items I stumbled upon several short articles dealing with the issue of immunity after SARS-Cov-2 infection. There is certainly no current consensus on the issue and, at the current time, no hard data to prove things one way or the other. This made me think about possible scenarios after the current first wave of infections. If the immunity that those who have been infected develop lapses within a year or two then we may well enter into a cycle of waves of infections, each modulated by the levels of social distancing and the numbers of infections in the region. This would imply that we might need to significantly reduce the density of interaction and concentrations of people in all areas of our lives.