From 1918 to 1920, the Spanish Flu inflected a quarter of the world’s population. On a recent Presbycast Episode, Kevin White (a PCA layman in Pittsburgh, PA who has studied church history) mentioned the research he’d been doing into the impact of the Spanish Flu on the Southern Presbyterian (PCUS); Kevin kindly shared his sources with me. Like in our present day with the COVID-19 virus, the Spanish Flu caused a great disruption on the life and ministry of the churches.
The report from the Committee on Publication and Sabbath Schools (p. 112) in the minutes of the 1919 General Assembly notes that 65% of Sabbath schools were closed for between three weeks and three months.
In the same meeting minutes, the Committee on Home Missions reports that
The last quarter of the year  brought the influenza epidemic to such a universal prevalence that for most of the time our Sunday Schools and churches and day schools had to be closed, and all public assembling were forbidden by secular authorities. (p. 40)
Many of the home missionaries and workers served in “the nursing and caring for the helpless sick of the communities. … The communities where many of our missionaries are laboring owe the saving of many lives to their untiring efforts” (p. 40). In the Oklahoma mission area, “Four ministers, one white and three native, have fallen during the year. The three natives… were among the most active and consecrated pastors. Great numbers of the faithful elders and leaders among the devoted women fell victims to the scourge” (p. 98)
The report from the Synod of Georgia notes that the moderator postponed their stated meeting which “exceeded his authority….” The Chairman of the Standing Committee of the Records of the Synod of Georgia’s report declaims that “owing to the unusual emergency caused by the influenza epidemic prevailing over the whole country at that time, this violation of the letter of our Church law in this instance may be excused” (p. 39).
God have mercy on us all.