evidence: In the last five camps affected—on average 3 weeks later—only 7.1 percent of influenza victims developed pneumonia. Only 17.8 percent of the soldiers who developed pneumonia died (Soper, 1918). [...] Many individuals who died during the pandemic succumbed to secondary bacterial pneumonia (Jordan, 1927; LeCount, 1919; Wolbach, 1919) because no antibiotics were available in 1918. However, a subset died rapidly after the onset of symptoms often with either massive acute pulmonary hemorrhage or pulmonary edema, often in less than 5 days (LeCount, 1919; Winternitz et al., 1920; Wolbach, 1919). In the hundreds of autopsies performed in 1918, the primary pathologic findings were confined to the respiratory tree and death was due to pneumonia and respiratory failure (Winternitz et al., 1920). These findings are consistent with infection by a well-adapted influenza virus capable of rapid replication throughout the entire respiratory tree (Reid and Taubenberger, 1999; Taubenberger et al., 2000). There was no clinical or pathological evidence for systemic circulation of the virus (Winternitz et al., 1920). [...] Policlinico. 1918, 6/30/18, 25(26), quoted in JAMA 71(9): 780