evidence: The majority of deaths were from bacterial pneumonia,[205][206][207] a common secondary infection associated with influenza. This pneumonia was itself caused by common upper respiratory-tract bacteria, which were able to get into the lungs via the damaged bronchial tubes of the victims.[208] The virus also killed people directly by causing massive hemorrhages and edema in the lungs.[207] Modern analysis has shown the virus to be particularly deadly because in animal trials it triggers an overreaction of the body's immune system (sometimes referred to as a cytokine storm).[81] The strong immune reactions of young adults were postulated to have ravaged the body, whereas the weaker immune reactions of children and middle-aged adults resulted in fewer deaths among those groups.[209] [...] - ^ "Bacterial Pneumonia Caused Most Deaths in 1918 Influenza Pandemic". National Institutes of Health. 23 September 2015. Archived from the original on 22 April 2016. Retrieved 17 April 2016. [...] - ^ "Gauze Mask to Halt Spread of Plague". The Washington Times. 27 September 1918. p. 3. Archived from the original on 8 October 2020. Retrieved 5 October 2020.