There was government censorship as well as self-censorship to avoid panic.
I'm referring more to private or diary type writings. My daughter took a class on plagues last winter. Since she was an Art History major, she wanted to write a term paper on art during the years of the black death. Despite having the vast resources of the U of Mich library at her disposal, she found that there really wasn't much art produced during that period. The horrible reality of what people were dealing with left no time or desire to depict it. It seems that the same thing happened during the flu pandemic.
I know that the war effort and government propaganda helped contribute to the spread of the flu. Those communities which took it very seriously, warned people to be very afraid of what might be coming, and instituted strict quarantines were actually spared. There was a community out west somewhere which would let no one into their town during the outbreak and no one got the flu there.