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.

An Outbreak of Dengue Virus Type 1 - Jiangxi Province, China, 2019.

What is known about this topic? Dengue fever is an acute febrile illness caused by four types of dengue virus (DENV 1-4), and is a mosquito-borne infectious disease. The incidence of dengue has increased dramatically around the world in recent decades. An estimated of 3.9 billion people in 128 countries are at risk of infection with dengue viruses, 70% of whom are in Asia. In 2017, the first local infections of dengue virus (DENV-2) in Jiangxi Province was reported in Zhanggong District, Ganzhou City. What is added by this report? From August to September 2019, the first dengue outbreak happened in Xin'gan County, where 81 local dengue fever cases were reported, 35 were laboratory-confirmed cases, and 46 were clinically-diagnosed cases; all cases were dengue virus type 1. The DENV-virus strains isolated from the cases of Xin'gan County were close to the strains isolated in Singapore (MF033254|25657|Singapore|2016) and Henan (MK905537|Henan201903|China: Henan Province|2019). What are the implications for public health practice? The outbreak might have been caused by imported cases or covert infections. The outbreak in Xin'gan County indicated that more proactive countermeasures should be taken during the dengue epidemic period such as intensifying surveillance for dengue cases, virus serotype, and Aedes vector density and strengthening cooperation with customs and tourism departments. Moreover, the outbreak should prompt training in medical institutions and improved ability for doctor's to diagnose dengue fever, which is very important for early detection of dengue cases and taking preventive measures.