Objective To analyze the initial symptoms and present traditional Chinese medicine（TCM） syndromes in patients with coronavirus disease 2019（COVID-19） through latent class analysis（LCA）

and to explore the core pathogenesis. Methods The elements of initial symptoms and present TCM syndromes in 650 COVID-19 patients were collected from 18 hospitals between February and March

2020. Elements with high prevalence rate were included. The included elements as binary variables were analyzed to figure out the core pathogenesis of COVID-19 as well as TCM syndrome classification for diagnosis with LCA method. The specific analysis process included probability parameterization

parameter estimation and model fitting

latent class analysis

and interpretation of the results using TCM theory. Results Elements of initial TCM symptoms were collected in 605 patients with COVID-19; and 17 out of 23 initial symptoms were included for LCA model with 3 classes. Class 1 included the syndrome elements belonging to damp（heat） pathogen

phlegm-damp and qi deficiency

indicating that the disease location was at lung. The syndrome elements included in Class 2 showed that the nature of disease was warm（heat） pathogen and qi deficiency. Class 3 was composed of the syndrome elements of warm（heat） pathogen

phlegm damp and qi deficiency

and revealed that the disease location was at lung. In conclusion

the nature of initial COVID-19 was mainly warm（heat） pathogen

phlegm damp

and qi deficiency

and the location of disease was wei-exterior and lung. In terms of present syndromes of COVID-19 from 650 patients

43 out of 55 elements were included in LCA model with 4 classes. Class 1

named damp-warm（heat） toxin accumulation and phlegm-heat obstructing lung

included the elements of warm（heat） pathogen

damp pathogen

phlegm pathogen

and qi deficiency

and identified lung as the disease location. Class 2 included syndrome of damp-warm（heat） toxic accumulation and spleen failing to transport

of which the nature elements were warm（heat） pathogen

damp pathogen and qi deficiency

and the disease location was at lung. In Class 3

the elements related to the nature of disease were damp pathogen

and warm（heat） pathogen

and the disease location was at spleen

showing the syndrome of damp-warm（heat） toxic accumulation and qi-yin damage. Class 4 indicated the syndrome of damp-warm（heat） toxic accumulation and heart-spleen deficiency

as elements of warm（heat） pathogen

damp pathogen

qi deficiency and yin deficiency were included

and spleen and heart were mostly involved. Conclusion The initial syndrome of COVID-19 was damp-warm（heat） toxic attacking wei-exterior

and then the lungs were invaded

and lung-qi insufficiency was present; the core pathogenesis of COVID-19 was damp-warm（heat） toxin accumulation

complemented with phlegm-heat obstructing lung

spleen failing to transport

qi-yin damage

or heart-lung deficiency.