Abstract
Objective
This study elaborated the natural history parameters of Delta variant, explored the differences in detection cycle thresholds (Ct) among cases.
Methods
Natural history parameters were calculated based on the different onset time and exposure time of the cases. Intergenerational relationships between generations of cases were calculated. Differences in Ct values of cases by gender, age, and mode of detection were analyzed statistically to assess the detoxification capacity of cases.
Results
The median incubation period was 4 days; the detection time for cases decreased from 25 to 7 h as the outbreak continued. The average generation time (GT), time interval between transmission generations (TG) and serial interval (SI) were 3.6 ± 2.6 days, 1.67 ± 2.11 days and 1.7 ± 3.0 days. Among the Ct values, we found little differences in testing across companies, but there were some differences in the gender of detected genes. The Ct values continuous to decreased with age, but increased when the age was greater than 60.
Conclusion
This epidemic was started from aggregation of factories. It is more reasonable to use SI to calculate the effective reproduction number and the time-varying reproduction number. And the analysis of Ct values can improve the positive detection rate and improve prevention and control measures.
【저자키워드】 COVID-19, Cycle threshold value, natural history, 【초록키워드】 Gender, Transmission, delta variant, Epidemic, Measures, cycle threshold, outbreak, Incubation period, Reproduction number, age, detection rate, Analysis, Generation time, average, aggregation, positive, parameter, Genes, objective, effective, difference, intergenerational, IMPROVE, Result, greater, analyzed, median, calculated, statistically, calculate, 【제목키워드】 China, Analysis, city, Xiamen,