American climatologist Jeffrey Shaman and epidemiologist Melvin Kohn meet to investigate the flu virus. The goal was to clarify the causes of flu outbreaks in winter. Both scientists collected data from older research to analyze the transmission of the virus and its ability to endure in its entirety. The data concluded that the main factor that increases the duration of the virus is low absolute humidity. Precisely because of heating, the humidity in homes is usually very low in winter and the virus has good conditions to progress.