Epidemiological characteristics of SARS-CoV-2 infection outbreak in Shanghai in the Spring of 2022
10.19428/j.cnki.sjpm.2022.22058
- VernacularTitle:上海市2022年春季新型冠状病毒感染暴发的流行病学特征分析
- Author:
Linfeng XIAN
1
;
Jiansheng LIN
2
;
Shichong YU
3
;
Yue ZHAO
1
;
Pei ZHAO
4
;
Guangwen CAO
1
Author Information
1. Faculty of Naval Medicine， Naval Medical University， Shanghai 200433， China
2. School of Medicine， Jinan University， Guangzhou， Guangdong 510632， China
3. Faculty of Pharmacy， Naval Medical University， Shanghai 200433， China
4. Guangxi Medical University Cancer Hospital， Nanning， Guangxi 530021， China
- Publication Type:Journal Article
- Keywords:
SARS-CoV-2;
asymptomatic carrier;
confirmed COVID-19 case;
outbreak;
dynamic trend
- From:
Shanghai Journal of Preventive Medicine
2022;34(4):294-299
- CountryChina
- Language:Chinese
-
Abstract:
ObjectiveTo investigate the epidemiological characteristics and analyze the incidence trend of SARS-CoV-2 infection in Shanghai， China， and compare with the characteristics of the infection in Jilin Province of China during the same period in 2022 and Wuhan at the beginning of 2020. MethodsInformation of new locally-transmitted confirmed SARS-CoV-2 cases， imported confirmed COVID-19 cases， local asymptomatic SARS-CoV-2 carriers and imported asymptomatic SARS-CoV-2 carriers in Shanghai from March 1 to April 18， 2022 was collected for descriptive analysis. ResultsFrom March 1 to April 18， 2022， a total of 397 933 locally-transmitted SARS-CoV-2 cases were reported in Shanghai. Of those， 27 613 were clinically confirmed cases and 21 were severe cases. Ten deaths were related to COVID-19. The pathogen is Omicron variant BA.2 of SARS-CoV-2. The number of the infected subjects increased rapidly after March 24 and lead to a disease outbreak. Severe and deceased cases had severe comorbidity and were mostly unvaccinated with SARS-CoV-2 vaccines. Asymptomatic SARS-CoV-2 carriers accounted for 93.06%， which is significantly higher than that in Jilin Province during the same period （48.07%， P<0.001）. Daily increase in the number of clinically confirmed COVID-19 cases in Shanghai in 2022 was much lower than that in Wuhan， Hubei Province， in 2020. Number of daily newly imported confirmed COVID-19 cases and imported asymptomatic SARS-CoV-2 carriers declined during this period. ConclusionThe Omicron variant in Shanghai 2022 is highly infectious and less pathogenic. Omicron variant BA.2 replicates rapidly in asymptomatic carriers， which makes the carriers the major source of infection. Full-term vaccination of inactivated SARS-CoV-2 vaccine might decrease the pathogenicity and fatality of SARS-CoV-2 variants. SARS-CoV-2 of the Omicron BA2 strain is likely transmitted through aerosols and droplets， which poses a great challenge to the control of the COVID-19 pandemic in large cities with high population density and sophisticated public transportation.
