[Lessons from the Russian Flu for the endgame of the current pandemic-an exit strategy for Germany].

Background: Since the beginning of the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) pandemic, Germany never formulated an explicit strategy so far. Topics continuously become disconnected from their origin and the justification for the lockdown gets out of focus, i.e. the reduction of mortality in the vulnerable population and age-groups, and the risk of an increased case fatality when the healthcare system-primarily intensive care capacity-would become overwhelmed. Methods: On the basis of knowledge which was already available before the current pandemic and knowledge which has been accumulated so far, refocusing and developing of an exit strategy for Germany is attempted. Results: The central goal in pandemics is to overcome the primary infection of the population by wild type infection or vaccination as quickly as possible and to achieve the herd immunity threshold. Only in this way can the virus lose its dangerous potential and a new endemic equilibrium can be achieved. The Russian Flu Pandemic from 1889-1892 by CoV OC43, today a pandemic scar from that time, can function as a role model. The successful vaccine development in unprecedented speed is a grace of historic dimension. Conclusions: The Russian Flu Pandemic was the most recent and largest coronavirus pandemic. After offering vaccination to all vulnerable groups (target population), the lockdown has to be ended as soon as possible. Vaccinations should continue to be offered to adults without established risk factors and the remaining population should be primed by infection with the wild virus. In spite of the rapid, successful development of a vaccine, time to avoid further disruptions is running out.