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Abstract

Background

COVID-19, caused by SARS-CoV-2, first appeared in China and subsequently developed into an ongoing epidemic. Understanding epidemiological factors characterising the transmission dynamics of this disease is of fundamental importance.

Aims

This study aimed to describe key epidemiological parameters of COVID-19 in Hong Kong.

Methods

We extracted data of confirmed COVID-19 cases and their close contacts from the publicly available information released by the Hong Kong Centre for Health Protection. We used doubly interval censored likelihood to estimate containment delay and serial interval, by fitting gamma, lognormal and Weibull distributions to respective empirical values using Bayesian framework with right truncation. A generalised linear regression model was employed to identify factors associated with containment delay. Secondary attack rate was also estimated.

Results

The empirical containment delay was 6.39 days; whereas after adjusting for right truncation with the best-fit Weibull distribution, it was 10.4 days (95% CrI: 7.15 to 19.81). Containment delay increased significantly over time. Local source of infection and number of doctor consultations before isolation were associated with longer containment delay. The empirical serial interval was 4.58–6.06 days; whereas the best-fit lognormal distribution to 26 certain-and-probable infector–infectee paired data gave an estimate of 4.77 days (95% CrI: 3.47 to 6.90) with right-truncation. The secondary attack rate among close contacts was 11.7%.

Conclusion

With a considerable containment delay and short serial interval, contact-tracing effectiveness may not be optimised to halt the transmission with rapid generations replacement. Our study highlights the transmission risk of social interaction and pivotal role of physical distancing in suppressing the epidemic.

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/content/10.2807/1560-7917.ES.2020.25.16.2000155
2020-04-23
2020-05-29
http://instance.metastore.ingenta.com/content/10.2807/1560-7917.ES.2020.25.16.2000155
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References

  1. Lai CC, Shih TP, Ko WC, Tang HJ, Hsueh PR. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and coronavirus disease-2019 (COVID-19): The epidemic and the challenges. Int J Antimicrob Agents. 2020;55(3):105924.  https://doi.org/10.1016/j.ijantimicag.2020.105924  PMID: 32081636 
  2. World Health Organization (WHO). Statement on the second meeting of the International Health Regulations (2005) Emergency Committee regarding the outbreak of novel coronavirus (2019-nCoV) 2020. Geneva: WHO; 2020. Available from: https://www.who.int/news-room/detail/30-01-2020-statement-on-the-second-meeting-of-the-international-health-regulations-(2005)-emergency-committee-regarding-the-outbreak-of-novel-coronavirus-(2019-ncov)
  3. World Health Organization (WHO). Coronavirus disease (COVID-19) outbreak. Geneva: WHO. [Accessed 21 Apr 2020]. Available from: https://www.who.int/westernpacific/emergencies/covid-19
  4. World Health Organization (WHO). Coronavirus disease 2019 (COVID-19). Situation Report – 24. Geneva: WHO; 13 Feb 2020. Available from:https://www.who.int/docs/default-source/coronaviruse/situation-reports/20200213-sitrep-24-covid-19.pdf?sfvrsn=9a7406a4_4
  5. Hong Kong Centre for Health Protection. CHP investigates highly suspected imported case of novel coronavirus infection 2020. Hong Kong: CHP; 2020. Available from: https://www.info.gov.hk/gia/general/202001/22/P2020012200982.htm
  6. Kwok KO, Wong V, Wei VWI, Wong SYS, Tang JW. Novel coronavirus (2019-nCoV) cases in Hong Kong and implications for further spread. J Infect. 2020;S0163-4453(20)30084-0.  https://doi.org/10.1016/j.jinf.2020.02.002  PMID: 32092391 
  7. Government of the Hong Kong Special Administrative Region. Hong Kong's multi-pronged response to COVID-19 2020; 2020. Available from: https://www.hketojakarta.gov.hk/doc/pdf/Factsheet_coronavirus_Mar_17_E.pdf
  8. Chen N, Zhou M, Dong X, Qu J, Gong F, Han Y, et al. Epidemiological and clinical characteristics of 99 cases of 2019 novel coronavirus pneumonia in Wuhan, China: a descriptive study. Lancet. 2020;395(10223):507-13.  https://doi.org/10.1016/S0140-6736(20)30211-7  PMID: 32007143 
  9. Kwok KO, Cowling B, Wei V, Riley S, Read JM. Temporal variation of human encounters and the number of locations in which they occur: a longitudinal study of Hong Kong residents. J R Soc Interface. 2018;15(138):20170838.  https://doi.org/10.1098/rsif.2017.0838  PMID: 29367241 
  10. Lau JT, Tsui H, Lau M, Yang X. SARS transmission, risk factors, and prevention in Hong Kong. Emerg Infect Dis. 2004;10(4):587-92.  https://doi.org/10.3201/eid1004.030628  PMID: 15200846 
  11. Lee SS, Wong NS. Probable transmission chains of Middle East respiratory syndrome coronavirus and the multiple generations of secondary infection in South Korea. Int J Infect Dis. 2015;38:65-7.  https://doi.org/10.1016/j.ijid.2015.07.014  PMID: 26216766 
  12. Government of the Hong Kong Special Administrative Region. Press releases 2020; 2020. Available from: https://www.coronavirus.gov.hk/eng/press_release.html
  13. Hong Kong Centre for Health Protection. Latest situation of cases of novel coronavirus infection 2020; 2020. Available from: https://www.chp.gov.hk/files/pdf/enhanced_sur_pneumonia_wuhan_eng.pdf
  14. Hong Kong Centre for Health Protection (CHP). Communicable Disease Surveillance Case Definitions 2020. Hong Kong: CHP; 2020. Available from: https://cdis.chp.gov.hk/CDIS_CENO_ONLINE/disease.html
  15. Pung R, Chiew CJ, Young BE, Chin S, Chen MI, Clapham HE, et al. Singapore 2019 Novel Coronavirus Outbreak Research Team. Investigation of three clusters of COVID-19 in Singapore: implications for surveillance and response measures. Lancet. 2020;395(10229):1039-46.  https://doi.org/10.1016/S0140-6736(20)30528-6  PMID: 32192580 
  16. Vink MA, Bootsma MC, Wallinga J. Serial intervals of respiratory infectious diseases: a systematic review and analysis. Am J Epidemiol. 2014;180(9):865-75.  https://doi.org/10.1093/aje/kwu209  PMID: 25294601 
  17. Fine PE. The interval between successive cases of an infectious disease. Am J Epidemiol. 2003;158(11):1039-47.  https://doi.org/10.1093/aje/kwg251  PMID: 14630599 
  18. Liu Y, Eggo RM, Kucharski AJ. Secondary attack rate and superspreading events for SARS-CoV-2. Lancet. 2020;395(10227):e47.  https://doi.org/10.1016/S0140-6736(20)30462-1  PMID: 32113505 
  19. Linton NM, Kobayashi T, Yang Y, Hayashi K, Akhmetzhanov AR, Jung SM, et al. Incubation Period and Other Epidemiological Characteristics of 2019 Novel Coronavirus Infections with Right Truncation: A Statistical Analysis of Publicly Available Case Data. J Clin Med. 2020;9(2):538.  https://doi.org/10.3390/jcm9020538  PMID: 32079150 
  20. Nishiura H, Linton NM, Akhmetzhanov AR. Serial interval of novel coronavirus (COVID-19) infections. Int J Infect Dis. 2020;93:284-6.  https://doi.org/10.1016/j.ijid.2020.02.060  PMID: 32145466 
  21. Thompson RN. Novel Coronavirus Outbreak in Wuhan, China, 2020: Intense Surveillance Is Vital for Preventing Sustained Transmission in New Locations. J Clin Med. 2020;9(2):498.  https://doi.org/10.3390/jcm9020498  PMID: 32054124 
  22. Kraemer M, Pigott D, Xu B, Hill S, Gutierrez B, Pybus O. Epidemiological Data from the nCoV-2019 Outbreak: Early Descriptions from Publicly Available Data 2020; 2020. Available from: http://virological.org/t/epidemiological-data-from-the-ncov-2019-outbreak-early-descriptions-from-publicly-available-data/337
  23. Chan JF, Yuan S, Kok KH, To KK, Chu H, Yang J, et al. A familial cluster of pneumonia associated with the 2019 novel coronavirus indicating person-to-person transmission: a study of a family cluster. Lancet. 2020;395(10223):514-23.  https://doi.org/10.1016/S0140-6736(20)30154-9  PMID: 31986261 
  24. Bi Q, Wu Y, Mei S, Ye C, Zou X, Zhang Z, et al. Epidemiology and Transmission of COVID-19 in Shenzhen China: Analysis of 391 cases and 1,286 of their close contacts 2020. Available from: https://www.medrxiv.org/content/10.1101/2020.03.03.20028423v3
  25. Ng Y, Li Z, Chua YX, Chaw WL, Zhao Z, Er B, et al. Evaluation of the Effectiveness of Surveillance and Containment Measures for the First 100 Patients with COVID-19 in Singapore - January 2-February 29, 2020. MMWR Morb Mortal Wkly Rep. 2020;69(11):307-11.  https://doi.org/10.15585/mmwr.mm6911e1  PMID: 32191691 
  26. Du Z, Xu X, Wu Y, Wang L, Cowling BJ, Meyers LA. Serial Interval of COVID-19 among Publicly Reported Confirmed Cases. Emerg Infect Dis. 2020;26(6).  https://doi.org/10.3201/eid2606.200357  PMID: 32191173 
  27. Li Q, Guan X, Wu P, Wang X, Zhou L, Tong Y, et al. Early Transmission Dynamics in Wuhan, China, of Novel Coronavirus-Infected Pneumonia. N Engl J Med. 2020;382(13):1199-207.  https://doi.org/10.1056/NEJMoa2001316  PMID: 31995857 
  28. Kwok KO, Li KK, Chan HHH, Yi YY, Tang A, Wei WI, et al. Community Responses during Early Phase of COVID-19 Epidemic, Hong Kong. Emerg Infect Dis. 2020;26(7).  https://doi.org/10.3201/eid2607.200500  PMID: 32298227 
  29. Government of the Hong Kong Special Administrative Region. HA enhanced laboratory surveillance programme extends to outpatients with mild symptoms 2020; 2020. Available from: https://www.info.gov.hk/gia/general/202002/18/P2020021800437.htm
  30. Lauer SA, Grantz KH, Bi Q, Jones FK, Zheng Q, Meredith HR, et al. The Incubation Period of Coronavirus Disease 2019 (COVID-19) From Publicly Reported Confirmed Cases: Estimation and Application. Ann Intern Med. 2020.  https://doi.org/10.7326/M20-0504  PMID: 32150748 
  31. Backer JA, Klinkenberg D, Wallinga J. Incubation period of 2019 novel coronavirus (2019-nCoV) infections among travellers from Wuhan, China, 20-28 January 2020. Euro Surveill. 2020;25(5).  https://doi.org/10.2807/1560-7917.ES.2020.25.5.2000062  PMID: 32046819 
  32. Pang X, Zhu Z, Xu F, Guo J, Gong X, Liu D, et al. Evaluation of control measures implemented in the severe acute respiratory syndrome outbreak in Beijing, 2003. JAMA. 2003;290(24):3215-21.  https://doi.org/10.1001/jama.290.24.3215  PMID: 14693874 
  33. Kwok KO, Lai F, Wei WI, Wong SYS, Tang JWT. Herd immunity - estimating the level required to halt the COVID-19 epidemics in affected countries. J Infect. 2020;S0163-4453(20)30154-7.  https://doi.org/10.1016/j.jinf.2020.03.027  PMID: 32209383 
  34. Kimball A, Hatfield KM, Arons M, James A, Taylor J, Spicer K, et al. Public Health – Seattle & King CountyCDC COVID-19 Investigation Team. Asymptomatic and Presymptomatic SARS-CoV-2 Infections in Residents of a Long-Term Care Skilled Nursing Facility - King County, Washington, March 2020. MMWR Morb Mortal Wkly Rep. 2020;69(13):377-81.  https://doi.org/10.15585/mmwr.mm6913e1  PMID: 32240128 
  35. Chen T, Wu D, Chen H, Yan W, Yang D, Chen G, et al. Clinical characteristics of 113 deceased patients with coronavirus disease 2019: retrospective study. BMJ. 2020;368:m1091.  https://doi.org/10.1136/bmj.m1091  PMID: 32217556 
  36. McMichael TM, Currie DW, Clark S, Pogosjans S, Kay M, Schwartz NG, et al. Epidemiology of Covid-19 in a Long-Term Care Facility in King County, Washington. N Engl J Med. 2020;NEJMoa2005412.  https://doi.org/10.1056/NEJMoa2005412  PMID: 32220208 
  37. Parodi E. Uncounted among coronavirus victims, deaths sweep through Italy's nursing homes. Reuters. 2020.
  38. Kwok KO, Leung GM, Lam WY, Riley S. Using models to identify routes of nosocomial infection: a large hospital outbreak of SARS in Hong Kong. Proc Biol Sci. 2007;274(1610):611-7.  https://doi.org/10.1098/rspb.2006.0026  PMID: 17254984 
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