Transmission dynamics and successful control measures of SARS-CoV-2 in the mega-size city of Guangzhou, China.
Medicine (Baltimore)
; 100(48): e27846, 2021 Dec 03.
Article
in English
| MEDLINE | ID: covidwho-1583962
ABSTRACT
ABSTRACT The severe acute respiratory syndrome coronavirus 2 has caused a worldwide pandemic. Control measures differ among countries and have a varying degree of effectiveness, which requires assessment. To evaluate the effectiveness of public health interventions of the coronavirus disease 2019 (COVID-19) in Guangzhou by 3 periods according to interventions:
January 7 to 22 (no intervention), January 23 to February 23 (implemented intensive interventions), and February 24 to May 17 (the normalization mode of COVID-19 prevention and control).We collected the information of 745 COVID-19 patients and their close contacts as well as control measures in Guangzhou from January 7 to May 17, 2020. We estimated the epidemiological characteristics, disease spectrum of COVID-19 cases, key time-to-event intervals, and effective reproduction number over the 3 periods. The basic reproduction number of severe acute respiratory syndrome coronavirus 2 was also calculated over period 1.Approximately 45.8%, 49.8%, and 4.4% of cases from close contacts were asymptomatic, symptomatic, and severe, respectively. The median incubation period was 5.3âdays (the percentiles of 2.5-97.5, 1.5-18.4âdays) and the median serial interval fitted with gamma distribution was 5.1âdays (the percentiles of 2.5-97.5, 0.8-15.9âdays). The estimated median of onset-to-quarantined time in Period 1 to 3 were 7.5, 3.4, and 2.9âdays (the percentiles of 2.5-97.5, 2.1-14.2, 3.9-14.7, and 6.0-20.0âdays) respectively and the median of onset-to-confirmation time in period 1 to 3 were 8.9, 4.9 and 2.4âdays (the percentiles of 2.5-97.5, 2.6-16.6, 0.9-14.6, and 0.5-11.8âdays). In period 1, the reproduction number was 0.9 (95% confidence interval, 0.5-1.4) and fluctuated below 1.0 before January 22 except for January 14. The effective reproduction number gradually decreased in the period 2 with the lowest point of 0.1 on February 20, then increased again since March 27 and reach a spike of 1.8 on April 12. The number decreased to below 1.0 after April 17 and decreased further to <0.2 after May 7 in the period 3.Under prospective dynamic observation, close contacts turned into infected cases could provide a spectrum of COVID-19 cases from real-world settings. The lockdown of Wuhan and closed-loop management of people arriving Guangzhou were effective in halting the spread of the COVID-19 cases to Guangzhou. The spread of COVID-19 was successfully controlled in Guangzhou by social distancing, wearing a face mask, handwashing, disinfection in key places, mass testing, extensive contact tracing, and strict quarantine of close contacts.
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
Communicable Disease Control
/
Disease Outbreaks
/
SARS-CoV-2
/
COVID-19
Type of study:
Cohort study
/
Experimental Studies
/
Observational study
/
Prognostic study
Limits:
Adult
/
Aged
/
Humans
/
Middle aged
/
Young adult
Country/Region as subject:
Asia
Language:
English
Journal:
Medicine (Baltimore)
Year:
2021
Document Type:
Article
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