Seasonal colds are not taken seriously: the symptoms usually pass within a few days and do not require special treatment other than raspberry tea and antipyretic medicine. But respiratory infections are an underestimated problem, and the data we have only shows the tip of the iceberg. What complications can the flu lead to and why viruses are not the main cause, said Sergey Netsov, Academician of the Russian Academy of Sciences, head of the Bio-Nanotechnology Laboratory at NSU. Read news in Max.