Latent period and incubation period with associated factors of COVID-19 caused by Omicron variant.
10.3760/cma.j.cn112150-20220926-00925
- VernacularTitle:新型冠状病毒Omicron变异株感染者的潜隐期、潜伏期及其相关因素分析
- Author:
Xin Li JIANG
1
;
Yan QIU
2
;
Yan Ping ZHANG
1
;
Peng YANG
3
;
Biao HUANG
4
;
Mei LIN
5
;
Ying YE
6
;
Feng GAO
1
;
Dan LI
1
;
Ying QIN
1
;
Yu LI
1
;
Zhong Jie LI
7
Author Information
1. Division of Infectious Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China.
2. Haidian District Center for Disease Control and Prevention,Beijing 100094, China.
3. Beijing Center for Disease Prevention and Control, Beijing 100013, China.
4. Jilin Provincial Center for Disease Control and Prevention, Changchun 130062, China.
5. Guangxi Center for Disease Control and Prevention, Nanning 530028, China.
6. Institute for Infectious Disease Prevention and Control,Henan Provincial Center for Disease Control and Prevention, Zhengzhou 450016, China.
7. Chinese Center for Disease Control and Prevention, Beijing 102206, China.
- Publication Type:Journal Article
- MeSH:
Male;
Humans;
Adult;
Adolescent;
Young Adult;
Middle Aged;
Infant, Newborn;
Infant;
Child, Preschool;
Child;
COVID-19;
SARS-CoV-2;
Infectious Disease Incubation Period;
Asymptomatic Infections
- From:
Chinese Journal of Preventive Medicine
2023;57(5):659-666
- CountryChina
- Language:Chinese
-
Abstract:
Objective: To estimate the latent period and incubation period of Omicron variant infections and analyze associated factors. Methods: From January 1 to June 30, 2022, 467 infections and 335 symptomatic infections in five local Omicron variant outbreaks in China were selected as the study subjects. The latent period and incubation period were estimated by using log-normal distribution and gamma distribution models, and the associated factors were analyzed by using the accelerated failure time model (AFT). Results: The median (Q1, Q3) age of 467 Omicron infections including 253 males (54.18%) was 26 (20, 39) years old. There were 132 asymptomatic infections (28.27%) and 335 (71.73%) symptomatic infections. The mean latent period of 467 Omicron infections was 2.65 (95%CI: 2.53-2.78) days, and 98% of infections were positive for nucleic acid test within 6.37 (95%CI: 5.86-6.82) days after infection. The mean incubation period of 335 symptomatic infections was 3.40 (95%CI: 3.25-3.57) days, and 97% of them developed clinical symptoms within 6.80 (95%CI: 6.34-7.22) days after infection. The results of the AFT model analysis showed that compared with the group aged 18-49 years old, the latent period [exp(β)=1.36 (95%CI: 1.16-1.60), P<0.001] and incubation period [exp(β)=1.24 (95%CI: 1.07-1.45), P=0.006] of infections aged 0-17 years old were prolonged. The latent period [exp(β)=1.38 (95%CI: 1.17-1.63), P<0.001] and the incubation period [exp(β)=1.26 (95%CI: 1.06-1.48), P=0.007] of infections aged 50 years old and above were also prolonged. Conclusion: The latent period and incubation period of most Omicron infections are within 7 days, and age may be a influencing factor of the latent period and incubation period.
