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Open Access 01-12-2024 | COVID-19 | Research

Transmission chains of the first local outbreak cause by Delta VariantB.1.617.2 COVID-19 in Guangzhou, Southern China

Authors: Chun Chen, Ke Li, Yong Huang, Chaojun Xie, Zongqiu Chen, Wenhui Liu, Hang Dong, Shujun Fan, Lirui Fan, Zhoubin Zhang, Lei Luo

Published in: BMC Infectious Diseases | Issue 1/2024

Abstract

Background

The first local outbreak of Delta Variant B.1.617.2 COVID-19 of China occurred in Guangzhou city, south China, in May 2021. This study analyzed the transmission chains and local cluster characteristics of this outbreak, intended to provide information support for the development and adjustment of local prevention and control strategies.

Methods

The transmission chains and local cluster characteristics of 161 local cases in the outbreak were described and analyzed. Incubation period, serial interval and generation time were calculated using the exact time of exposure and symptom onset date of the cases. The daily number of reported cases and the estimated generation time were used to estimate the effective reproduction number (Rt).

Results

We identified 7 superspreading events who had more than 5 next generation cases and their infected cases infected 70.81%(114/161) of all the cases transmission. Dining and family exposure were the main transmission routes in the outbreak, with 29.19% exposed through dining and 32.30% exposed through family places. Through further analysis of the outbreak, the estimated mean incubation period was 4.22 (95%CI: 3.66–4.94) days, the estimated mean generation time was 2.60 (95%CI: 1.96–3.11) days, and the estimated Rt was 3.29 (95%CI: 2.25–5.07).

Conclusions

Classification and dynamically adjusted prevention and control measures had been carried out according to analysis of transmission chains and epidemical risk levels, including promoting nucleic acid screening at different regions and different risk levels, dividing closed-off area, controlled area according to the risk of infection, raising the requirements of leaving Guangzhou. By the above control measures, Guangzhou effectively control the outbreak within 28 days without implementing a large-scale lockdown policy.

Yang W, Shaman J. COVID-19 pandemic dynamics in India, the SARS-CoV-2 Delta variant and implications for vaccination. J R Soc Interface. 2022;19(191):20210900.CrossRefPubMedPubMedCentral

Lopez Bernal J, Andrews N, Gower C, Gallagher E, Simmons R, Thelwall S, Stowe J, Tessier E, Groves N, Dabrera G, et al. Effectiveness of Covid-19 Vaccines against the B.1.617.2 (Delta) Variant. N Engl J Med. 2021;385(7):585–94.CrossRefPubMed

Lloyd-Smith JO, Schreiber SJ, Kopp PE, Getz WM. Superspreading and the effect of individual variation on disease emergence. Nature. 2005;438(7066):355–9.CrossRefPubMedPubMedCentral

Ac D. DV H: Bootstrap methods and their application. Cambridge: Cambridge University Press; 1997.

Wallinga J, Lipsitch M. How generation intervals shape the relationship between growth rates and reproductive numbers. Proc Biol Sci. 2007;274(1609):599–604.PubMed

headquarters GNcppaC. Circular on Routine Prevention and Control of COVID-19 (No. 9). https://www.gz.gov.cn/xw/jrgz/content/post_5832426.html. Accessed 16 Oct 2022.

Wan Y, Shang J, Graham R, Baric RS, Li F. Receptor Recognition by the Novel Coronavirus from Wuhan: an Analysis Based on Decade-Long Structural Studies of SARS Coronavirus. J Virol. 2020;94(7):1–9.

Li Q, Guan X, Wu P, Wang X, Zhou L, Tong Y, Ren R, Leung KSM, Lau EHY, Wong JY, et al. Early Transmission Dynamics in Wuhan, China, of Novel Coronavirus-Infected Pneumonia. N Engl J Med. 2020;382(13):1199–207.CrossRefPubMedPubMedCentral

Han Y, Yang L, Jia K, Li J, Feng S, Chen W, Zhao W, Pereira P. Spatial distribution characteristics of the COVID-19 pandemic in Beijing and its relationship with environmental factors. Sci Total Environ. 2021;761:144257.CrossRefPubMed

10.

Zhang Y, Gao WJ, Wang Y, Wang XL, Cui SJ, Jia L, Wang QY, Li LM. Epidemiological characteristics of COVID-19 cases in outbreak in Xinfadi market in Beijing. Zhonghua liu xing bing xue za zhi = Zhonghua liuxingbingxue zazhi. 2021;42(3):1–5.

11.

Prevention CfDCa. Scientific Brief: SARS-CoV-2 transmission. https://www.cdcgov/coronavirus/2019-ncov/science/science-briefs/sars-cov-2-transmissionhtml.2021.

12.

Katlama C, Dudoit Y, Huyard J, Blanc C, Soulié C, Schneider L, Faycal A, Lenclume L, Hamani N, Qatib N, et al. Household transmission of SARS-CoV-2 infection in the Paris/Ile-de-France area. Eur J Clin Microbiol Infect Dis. 2022;41(3):445–54.CrossRefPubMedPubMedCentral

13.

Guy GP Jr, Lee FC, Sunshine G, McCord R, Howard-Williams M, Kompaniyets L, Dunphy C, Gakh M, Weber R, Sauber-Schatz E, et al. Association of State-Issued Mask Mandates and Allowing On-Premises Restaurant Dining with County-Level COVID-19 Case and Death Growth Rates - United States, March 1-December 31, 2020. MMWR Morb Mortal Wkly Rep. 2021;70(10):350–4.CrossRefPubMedPubMedCentral

14.

Li Y, Qian H, Hang J, Chen X, Cheng P, Ling H, Wang S, Liang P, Li J, Xiao S, et al. Probable airborne transmission of SARS-CoV-2 in a poorly ventilated restaurant. Build Environ. 2021;196:107788.CrossRefPubMedPubMedCentral

15.

Adam DC, Wu P, Wong JY, Lau EHY, Tsang TK, Cauchemez S, Leung GM, Cowling BJ. Clustering and superspreading potential of SARS-CoV-2 infections in Hong Kong. Nat Med. 2020;26(11):1714–9.CrossRefPubMed

16.

Wu Y, Kang L, Guo Z, Liu J, Liu M, Liang W. Incubation Period of COVID-19 Caused by Unique SARS-CoV-2 Strains: A Systematic Review and Meta-analysis. JAMA Netw Open. 2022;5(8):e2228008.CrossRefPubMedPubMedCentral

17.

Luo L, Liu D, Liao X, Wu X, Jing Q, Zheng J, Liu F, Yang S, Bi H, Li Z, et al. Contact Settings and Risk for Transmission in 3410 Close Contacts of Patients With COVID-19 in Guangzhou, China : A Prospective Cohort Study. Ann Intern Med. 2020;173(11):879–87.CrossRefPubMed

18.

Madewell ZJ, Yang Y, Longini IM Jr, Halloran ME, Vespignani A, Dean NE. Rapid review and meta-analysis of serial intervals for SARS-CoV-2 Delta and Omicron variants. BMC Infect Dis. 2023;23(1):429.CrossRefPubMedPubMedCentral

19.

Ganyani T, Kremer C, Chen D, Torneri A, Faes C, Wallinga J, Hens N. Estimating the generation interval for coronavirus disease (COVID-19) based on symptom onset data, March 2020. Euro Surveill. 2020;25(17):1–8.

20.

Geismar C, Nguyen V, Fragaszy E, Shrotri M, Navaratnam AMD, Beale S, Byrne TE, Fong WLE, Yavlinsky A, Kovar J, et al. Bayesian reconstruction of SARS-CoV-2 transmissions highlights substantial proportion of negative serial intervals. Epidemics. 2023;44:100713.CrossRefPubMed

21.

Dougherty K, Mannell M, Naqvi O, Matson D, Stone J. SARS-CoV-2 B.1.617.2 (Delta) Variant COVID-19 Outbreak Associated with a Gymnastics Facility - Oklahoma, April-May 2021. MMWR Morb Mortal Wkly Rep. 2021;70(28):1004–7.CrossRefPubMedPubMedCentral

22.

Williams SV, Vusirikala A, Ladhani SN, Fernandez Ruiz De Olano E, Iyanger N, Aiano F, Stoker K, Gopal Rao G, John L, Patel B, et al. An outbreak caused by the SARS-CoV-2 Delta (B.1.617.2) variant in a care home after partial vaccination with a single dose of the COVID-19 vaccine Vaxzevria, London, England, April 2021. Euro Surveill. 2021;26(27):1–5.

Title: Transmission chains of the first local outbreak cause by Delta VariantB.1.617.2 COVID-19 in Guangzhou, Southern China
Authors: Chun Chen
Ke Li
Yong Huang
Chaojun Xie
Zongqiu Chen
Wenhui Liu
Hang Dong
Shujun Fan
Lirui Fan
Zhoubin Zhang
Lei Luo
Publication date: 01-12-2024
Publisher: BioMed Central
Keyword: COVID-19
Published in: BMC Infectious Diseases / Issue 1/2024
Electronic ISSN: 1471-2334
DOI: https://doi.org/10.1186/s12879-023-08819-3

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