[Typical case analysis of COVID-19 cluster epidemic in Shaanxi, 2020].

Objective: By analyzed the transmission patterns of 4 out of the 51 COVID-19 cluster cases in Shaanxi province to provide evidences for the COVID-19 control and prevention. Methods: The epidemiological data of RT-PCR test-confirmed COVID-19 cases were collected. Transmission chain was drawn and the transmission process was analyzed. Results: Cluster case 1 contained 13 cases and was caused by a family of 5 who traveled by car to Wuhan and returned to Shaanxi. Cluster case 2 had 5cases and caused by initial patient who participated family get-together right after back from Wuhan while under incubation period. Cluster case 3 contained 10 cases and could be defined as nosocomial infection. Cluster case 4 contained 4 cases and occurred in work place. Conclusion: Higher contact frequency and smaller places were more likely to cause a small-scale COVID-19 cluster outbreak, with potential longer incubation period. COVID-19 control strategies should turn the attention to infection prevention and control in crowded places, management of enterprise resumption and prevention of nosocomial infection.

[Epidemiological characteristics of COVID-19 in Shaanxi province].

Objective: To understand the incidence trend and epidemiological characteristics of COVID-19 in Shaanxi province. Methods: The incidence data of COVID-19 reported in Shaanxi as of 22 February, 2020 were collected for an epidemiological descriptive analysis. Results: A total of 245 confirmed cases of COVID-19 were reported in Shaanxi. Most cases were mild (87.76%). As time passed, the areas where confirmed cases were reported continued to increase. The case number in Xi'an was highest, accounting for nearly half of the total reported cases in the province. The epidemic pattern in Shaanxi had gradually shifted from imported case pattern to local case pattern, and the transmission of local cases was mainly based on family cluster transmission. The confirmed cases from different sources had caused the secondary transmission in Shaanxi. After February 7, the number of reported cases began to fluctuate and decrease stably, indicating a decrease-to-zero period. Conclusions: At present, the overall epidemic of COVID-19 in Shaanxi has gradually been mitigated. However, considering the approaching of return to work and study and the increasing of imported cases from other countries, the prevention and control of COVIS-19 in Shaanxi will face new challenges.

[Relationship between reproductive history and preterm births in the last pregnancy, in Shaanxi province].

Objective: To analyze the incidence of preterm delivery among single live neonates and the association between maternal reproductive history and preterm birth. Methods: A questionnaire survey was conducted on reproductive history among women at childbearing age who were selected through multi-stage stratified random sampling method in Shaanxi, during 2010-2013. Samples would include women at childbearing age and in pregnancy or having had definite pregnancy outcomes. Results: A total of 29 608 women at childbearing age with their infants, were studied. The overall incidence of premature delivery among the single live birth neonates under this study, was 2.7% during 2010-2013. Results from the logistic regression model showed that factors as: having had history with preterm delivery (OR=7.99, 95%CI: 5.59-11.43), age of the mothers, older than 35 (OR= 2.03, 95% CI: 1.59-2.59) and with history of birth defects (OR=1.54, 95% CI: 1.01-2.34) were at higher risks for premature delivery in neonates. Intervals on pregnancies between 3-4 years (compared with ≤2 years, OR=0.74, 95% CI: 0.58-0.93), between 5-6 years (compared with ≤2 years, OR=0.66, 95%CI: 0.52-0.82), or> 6 years (compared with ≤2 years, OR=0.48, 95%CI:0.37-0.61) together with numbers of parity as 1 (compared with primiparas, OR=0.80, 95%CI: 0.67-0.95), as ≥2 (compared with primiparas, OR=0.62, 95% CI: 0.39-0.97) etc. were protective factors to preterm delivery. Factors as: history of preterm delivery, mothers age (older than 35 years) and intervals of pregnancy, appeared influential to the age of gestation, under the ordinal polytomous logistic regression analysis. Conclusion: The incidence of preterm births among single live birth neonates in Shaanxi was lower than the average national level. Programs related to health care services prior to conception and during pregnancy, together with increasing the self-care consciousness of childbearing aged women etc, should all be strengthened in order to reduce the occurrence of preterm birth, in Shaanxi province.

[Factors related to the influence on congenital malformation of body surface in Shaanxi province].

Objective: To investigate the influencing factors on congenital malformation of body surface. Methods: Multi-stage stratified random sampling method was adopted. A questionnaire survey was conducted among the childbearing aged women who experienced more than 28 weeks pregnancy or having definite pregnancy outcomes in Shaanxi, during 2010-2013. Results: Results from the logistic regression model showed that factors as: intrahepatic cholestasis of pregnancy (OR=21.76, 95%CI: 4.46-106.25), histories with abnormal pregnancy or reproduction (OR=11.88, 95%CI: 9.14-15.45), having birth defects in the family (OR=6.15, 95%CI: 2.66-14.23), being twins (OR=5.74, 95% CI: 3.34-9.86), being worker (compared with others, OR=2.47, 95% CI: 1.30-4.68) or farmer (compared with others, OR=1.91, 95%CI: 1.14-3.20), less than 4 times of antenatal care (compared with >7, OR=1.84, 95% CI: 1.28-2.64), occupational exposure to related risks during pregnancy (OR=1.74, 95% CI: 1.26-2.42), mother's hometown was from mid-part of Shaanxi (compared with northern Shaanxi, OR=1.65, 95%CI: 1.20-2.28), mother's native residence was from the rural areas (OR=1.75, 95% CI: 1.13-2.71), drug use (OR=1.64, 95% CI: 1.26-2.13) etc. were risk factors for congenital malformation of body surface. Iron supplement during pregnancy (OR=0.46, 95%CI: 0.21-0.99) appeared as protective factor for congenital malformation of body surface. Conclusion: The following factors seemed to be of risk for congenital malformation of body surface, including: mother's native area was from the middle part of Shaanxi and living in rural area, being worker or farmer, histories of abnormal pregnancy and reproduction, history of birth defects in the family, being twins, with antenatal care less than 4 times, occupational exposure to dangerous materials, drug use, intrahepatic cholestasis during pregnancy etc.