No Clear Symptoms, No Containment
The reason that the outbreak of the “Spanish flu” turned into a pandemic, was not because there was no idea of how to combat it. During that time, epidemics were a well-known phenomenon and there were measures, such as isolation and other hygienic practices, that frequently kept them at bay. In the case of the flu pandemic of 1918, it was extremely difficult to implement these measures, because the virus was new and its symptoms were too unclear, as mentioned in the quote by the head of the responsible Department. The plans to make it obligatory for doctors to report cases to the officials were viewed as unworkable, because nobody was able to verify with certainty if a patient had actually contracted the “Spanish Flu”.

“Unfortunately, making it obligatory to report Spanish Flu infections makes no real sense, because it has no clearly distinct markers, because the pathogen of the epidemic is unknown, and because strictly isolating those infected does not appear feasible due to the massive scale of the epidemic. False diagnoses are also common, as the symptoms of the Spanish Flu are similar to those of a cold with a fever, bronchitis with fever, and other illnesses.”
Click on this link for the entire issue of the Neue Freie Presse, October 18, 1918