Spatiotemporal patterns of lung disease in China before 2019: A brief analysis of two nationally representative surveys.

Little is publicly known about the conditions surrounding the emergence of COVID in China. Using two nationally representative datasets, the China Family Panel Studies (CFPS) and the China Health and Retirement Longitudinal Study (CHARLS), we engage in a descriptive analysis of spatiotemporal patterns of lung and other diseases before 2019. In both datasets, the incidence of lung disease in 2018 was elevated in Hubei province relative to other provinces. The incidence of psychiatric and nervous system disease was elevated as well. Overall, the evidence is consistent with many possible explanations. One conjecture is that there was an outbreak of influenza in central China, which implies the conditions that increased the susceptibility to influenza also facilitated the later spread of COVID. Another conjecture, though less likely, is that COVID was circulating at low levels in the population in central China during 2018. This study calls for more investigation to understand the conditions surrounding the emergence of COVID.