The infectivity and transmission capacity of COVID-2019 cases during the incubation period are not very clear. The manuscript described a cluster to provide information for research on incubation period infection. We collected the required data from "Public Health Emergency Reporting Management Information System", epidemiological questionnaires for the cases, and laboratories. The cluster involved four generations, each of which was transmitted to the next generation during the incubation period. The time was 2-7 days, 6-7days, 3-8 days and 9 days prior to onset. As of March 11, the fourth-generation cases had no symptoms. Combined with the epidemiological data, we inferred that the source of the cluster was caused by the first-generation, who contacted with more than ten Wuhan people during the annual meeting from January 15 to 16. Two cases in this cluster were tested positive again during isolation and observation after discharge. We determined incubation period was infectious, and confirmed that it was contagious 9 days before the onset. The patients who were discharged might need to be observed for a period of time. This study was useful for the practical work, such as in the investigation of close contacts.

Hand, foot, and mouth disease (HFMD) has brought millions of attacks and a substantial burden in the Asia-Pacific region. Previous studies assessed disease risks around the world, which demonstrated great heterogeneity, and few determined the modification effect of social factors on temperature–disease relationship. We conducted a time-series study to evaluate the temperature-associated HFMD morbidity risk using daily data (from 2011 to 2017) and to identify potential modifiers relating to urban–rural status and aggregation mode of children. By applying a distributed lag nonlinear model (DLNM) and controlling for time-varying factors and other meteorological factors, we found that the relationship between daily mean temperature and the cumulative risk of HFMD was an approximately M-shaped curve. The effects of higher temperature appeared to be greater and more persistent than those of lower temperature. With the reference of −6°C, the cumulative relative risk (RR) values of high temperature (95 percentile) and low temperature (5 percentile) were 3.74 (95% CI: 2.50–5.61) and 1.72 (95% CI: 1.24–2.37) at lag 4–7, respectively. Temperature-associated HFMD morbidity risks were more pronounced among rural children and those attending kindergartens or schools at specific lags and temperatures. Relative risk values for temperature–disease association was highest among the 3- to 6-year group, whereas no gender difference was observed. Studying effect estimates and their modifications using the DLNM on a daily scale helps to identify susceptible groups and guide policy-making and resource allocation according to specific local conditions.