摘要
Objective:To explore the epidemiological characteristics of Corona Virus Disease 2019(COVID-19)Delta variant infection in children in Xi'an and Baoji.Methods:According to the official information released by Shaanxi Province,the information of confirmed cases in Xi'an(December 20,2021 to January 8,2022)and Baoji(March 8 to March 27,2022)were collected respectively.Records include age,sex,residential address,community and other basic information.Isolation mode,isolation time,morbidity and positive time of viral nucleic acid test,vaccination,clinical typing,close contact personnel,cluster incidence situation and the social activity tracking of the confirmed cases were collected,and the data were statistically analyzed.Results:In 20 days,there were 281 infected children in Xi'an,accounting for 14.48%of the total cases(1,940 cases),including 154 boys(54.8%)and 127 girls(45.20%).The number of diagnosed children in Baoji City(55 cases)is 19.57%of that in Xi'an(55/281),but accounts for 23.31%of the total number of cases(236 cases)in Baoji(this ratio is higher than that of 14.48%in Xi'an).Among the 55 cases of children,there are 33 males(60.00%)and 22 females(40.00%).The proportion of male children in both cities is higher.The median age of diagnosed children in Xi'an was 7.0 years(IQR:1.0-13.0 years old),and the age range was 4 d-18 years old,while the median age of Baoji children was 9.0 years old(IQR:5.0-17.0 years old),ranging from 3 months to 18 years old.The number of children vaccinated in Xi'an and Baoji was positively correlated with the number of infected children.The vaccination rates of children in Xi'an and Baoji were 64.06%and 52.73%,respectively.The vaccination rates of infants(≤1 year old)in both cities were 18.52%and 14.29%,respectively.On the whole,the number of new child cases in the two cities increased first and then decreased.The peak number of new child cases in Xi'an was 39(10th day of statistics),while that of Baoji was 13(6th day of statistics).The peak in Xi'an comes later and the epidemic lasts longer.Among the children in Xi'an,201(71.53%)had a history of close contact,55(19.57%)had no clear history of COVID-19 infection,and were positive after actively participating in the nucleic acid test of all members of the community,of which 54(98.18%)were primary and middle school students.54 cases(98.18%)of Baoji children had a history of close contact,of which 20 cases were infected by the confirmed case number 62 officially announced on March 10.The time to be positive for viral nucleic acid test in children after isolation was 1-14 days.The positive rate of children in Xi'an reached 85.41%(240/281)after 7 days of isolation,and the highest peak of positive detection was on the third day of isolation(84 cases).After 7 days of isolation,45 cases were positive in Baoji,accounting for 81.82%(45/55).The highest peak of positive detection was on the 5th day of isolation(11 cases).The regional distribution of infected children in Xi'an was the highest in Yanta District(137 cases),followed by High-tech Zone(42 cases)and Lianhu District(29 cases).The main manifestations of COVID-19 in Xi'an were light(278 cases,98.93%),common type(3 cases,1.07%),light in Baoji(54 cases,98.18%),and common type(1 case,1.82%).Through general clinical treatment(including traditional Chinese medicine treatment and symptomatic treatment),all were cured.Conclusion:Delta variant increases the susceptibility of children to infection,which spreads rapidly mainly through close family contact and community concealment,so it is necessary to study better early diagnosis and prevention and control measures.
