At the Chair of Building and Indoor Climate Technology, E.ON Energy Research Centre, RWTH Aachen University, a comprehensive study in German was published at the end of February 2021 on the topic of "The influence of air humidity on people and their health". In summary, the study is about determining the optimum air humidity for humans in closed rooms.
EBC, E.ON, RWTH
EBC (Institute for Energy Efficient Buildings and Indoor Climate), E.ON Energy Research Center, RWTH Aachen University