Estimation of Incubation Period and Serial Interval for SARS-CoV-2 in Jiangxi, China, and an Updated Meta-Analysis.

INTRODUCTION: This paper aims to estimate the incubation period and serial intervals for SARS-CoV-2 based on confirmed cases in Jiangxi Province of China and meta-analysis method. METHODOLOGY: Distributions of incubation period and serial interval of Jiangxi epidemic data were fitted by "fitdistrplus" package of R software, and the meta-analysis was conducted by "meta" package of R software. RESULTS: Based on the epidemic data of Jiangxi, we found the median days of incubation period and serial interval were 5.9 days [IQR: 3.8 - 8.6] and 5.7 days [IQR: 3.6 - 8.3], respectively. The median days of the infectivity period at pre-symptomatic was 1.7 days [IQR: 1.1 - 2.4]. The meta-analysis based on 64 papers showed the pooled means of the incubation period and serial interval were 6.25 days (95% CrI: 5.75 - 6.75) and 5.15 days (95% CrI: 4.73 - 5.57), respectively. CONCLUSIONS: Our results contribute to a better understanding of COVID-19 and provide useful parameters for modelling the dynamics of disease transmission. The serial interval is shorter than the incubation period, which indicates that the patients are infectious at pre-symptomatic period, and isolation of detected cases alone is likely to be difficult to halt the spread of SARS-CoV-2.

[Retrospective analysis of human avian influenza A (H10N8) virus infection in Jiangxi province].

OBJECTIVE: To analyze and discuss the source and epidemic disposition of human infection with avian influenza A (H10N8) virus. METHODS: Epidemiological surveys were used to collect related data and RT-PCR was applied to detect the specimens collected from cases, close contacts related exposure to live poultry markets. Data were analyzed descriptively. RESULTS: Three cases were discovered by surveillance on patients with severe pneumonia, two of the three died, but one in the hospital with the course over 6 months. All the three cases had histories of exposure to live poultry or related markets. Lower respiratory tract gargle aspirate samples of 3 patients were detected by Nanchang Municipal Center for Disease Control and Prevention (CDC) and Jiangxi Provincial CDC, and the results showed the influenza 2009pdmH1, H3, H5, H7, H9 subtypes negative. Specimen of patient 1 and 2 was positive for influenza A universal primers. Specimen of patient 3 was positive for H10N8 detected by Chinese National Influenza Center. All 33 close contacts of the patients were negative for H10N8 virus. Positive rate of the total poultry environmental specimens collected from the cases exposure markets was 5.19%. No new cases were found, after the prevention and control messages were implemented. CONCLUSION: Three cases of H10N8 avian influenza virus infection province might be associated with exposure to live poultry market in Jiangxi.