Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Oct;50(10):2121-2131.
doi: 10.18502/ijph.v50i10.7516.

Factors Affecting COVID-19 Transmission and Modelling of Close Contact Tracing Strategies

Shahram Yazdani  1 , Majid Heydari  1 , Zeynab Foroughi  2 , Hadi Jabali  2
Affiliations

Factors Affecting COVID-19 Transmission and Modelling of Close Contact Tracing Strategies

Shahram Yazdani et al. Iran J Public Health. 2021 Oct.

Abstract

Background: Close contact tracing is an essential measure that countries are applying to combat the epidemic of COVID-19. The purpose of contact tracing is to rapidly identify potentially infected individuals and prevent further spread of the disease. In this study, based on the factors affecting the COVID-19 transmission, a scoring protocol is provided for close contact tracing.

Methods: First, the factors affecting the COVID-19 transmission in close contacts were identified by a rapid review of the literature. Data were gathered by searching the Embase, PubMed, Google Scholar, and Scopus databases. Then, by formulating and scoring the identified factors with two sessions of the expert panel, close contact transmission risk score determined, and a protocol for contacts tracing was designed.

Results: Close contact transmission risk depends on the contact environment characteristics, the infectivity (virus shedding) of the sentinel case, and contact characteristics. Based on these factors, the close contact transmission risk score and contact tracing protocol were prepared.

Conclusion: The close contact transmission risk scores will provide the ability to contact classifications and developing specific tracing strategies for them. Given that there are not any specific treatments for COVID-19 and lack of universal vaccination, applying nonpharmaceutical measures such as contact tracing along with physical distancing is very crucial. Therefore, we recommended this model to the evaluation of exposure risk and contact tracing.

Keywords: COVID-19; Close contact tracing; Protocol; Transmission.

PubMed Disclaimer

Conflict of interest statement

Conflict of interest The authors declare that there is no conflict of interest.

Figures

Fig. 1:
Fig. 1:
Contact Environment Risk Score (CERS: 7–30)
Fig. 2:
Fig. 2:
Actual viral shedding by sentinel case
Fig. 3:
Fig. 3:
Infectivity score of unobservant sentinel case
Fig. 4:
Fig. 4:
Close Contact Risk Score (CCRS: 0–30)
Fig. 5:
Fig. 5:
Close contact tracing protocol
See this image and copyright information in PMC

References

    1. Harapan H, Itoh N, Yufika A, et al. (2020). Coronavirus disease 2019 (COVID-19): A literature review. J Infect Public Health, 13(5), 667–673. - PMC - PubMed
    1. Keeling MJ, Hollingsworth TD, Read JM. (2020). Efficacy of contact tracing for the containment of the 2019 novel coronavirus (COVID-19). J Epidemiol Community Health, 74(10), 861–866. - PMC - PubMed
    1. Burke RM, Midgley CM, Dratch A, et al. (2020). Active monitoring of persons exposed to patients with confirmed COVID-19 United States, January–February 2020. MMWR Morb Mortal Wkly Rep, 69(9):245–246. - PMC - PubMed
    1. World Health Organization (2020). The first few X cases and contacts (FFX) investigation protocol for coronavirus disease 2019 (COVID-19), 23 February 2020, version 2.2. World Health Organization. https://apps.who.int/iris/handle/10665/332023
    1. European Centre for Disease Prevention and Control (2020). Contact tracing: Public health management of persons, including healthcare workers, having had contact with COVID-19 cases in the European Union-second update. ECDC, Stockholm.

LinkOut - more resources