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Year : 2022  |  Volume : 15  |  Issue : 1  |  Page : 43-48  

Use of contact tracing as a pivotal tool to curb the COVID-19 transmission in the urban part of Western Maharashtra

Department of Community Medicine, Armed Forces Medical College, Pune, Maharashtra, India

Date of Submission30-Nov-2020
Date of Decision17-Feb-2021
Date of Acceptance22-Feb-2021
Date of Web Publication13-May-2021

Correspondence Address:
Arun Kumar Yadav
Department of Community Medicine, Armed Forces Medical College, Wanowrie, Pune - 411 040, Maharashtra
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/mjdrdypu.mjdrdypu_667_20

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Introduction: Contact tracing is an essential public health response to infectious disease outbreaks, principally in the early stages of an outbreak when specific treatments are limited. Importation of novel coronavirus (SARS CoV-2) from Hubei province China and elsewhere into the world highlights the need to recognize the power of contact tracing as a preventive measure. This study was performed to estimate the SARS CoV-2 transmission among the contacts of confirmed cases of coronavirus disease-19 (COVID-19). Methods: The present study included data from contact tracing performed on confirmed COVID-19 cases admitted in the tertiary care hospital of western Maharashtra. Contacts were categorized into high-risk and low-risk contacts. Contacts were quarantined in home or institute, and reverse transcription–polymerase chain reaction (RT-PCR) was done as per the COVID-19 testing strategy. Contacts were admitted once they were RT-PCR-confirmed COVID-19 positive. Results: Out of 471 COVID-19 cases, 104 (22.08%) were females and 367 (77.92%) were males. A total of 2617 contacts were traced with the mean (standard deviation) of 5.56 (8.52). Of these 2617 contacts, 289 (11.04%) contacts became RT-PCR-confirmed positive COVID-19 cases. Out of 471 COVID-19 cases, 271 (46.7) were the contacts of RT-PCR-confirmed COVID-19 cases, and from them, 92 (42.4%) were asymptomatic at the time of admission. Conclusion: The contact tracing strategy in India helped to identify a sufficient proportion of infected individuals, and due to that, subsequent spread of the disease could be prevented. However, the complete achievement will depend on the rapid detection of cases and isolation of contacts. With the increasingly large number of cases globally once in between the null period, this strategy can be effectively utilized to contain the spread of disease.

Keywords: COVID-19, disease transmission, high-risk contacts, low-risk contacts

How to cite this article:
Kansara NK, Yadav AK. Use of contact tracing as a pivotal tool to curb the COVID-19 transmission in the urban part of Western Maharashtra. Med J DY Patil Vidyapeeth 2022;15:43-8

How to cite this URL:
Kansara NK, Yadav AK. Use of contact tracing as a pivotal tool to curb the COVID-19 transmission in the urban part of Western Maharashtra. Med J DY Patil Vidyapeeth [serial online] 2022 [cited 2022 Aug 20];15:43-8. Available from: https://www.mjdrdypv.org/text.asp?2022/15/1/43/315911

  Introduction Top

In public health, contact tracing is “Identification of people in close contact with someone who is infected with the virus.” Contact tracing is the main central public health reaction to any infectious disease outbreaks. It is being done particularly in the initial stage of an outbreak when there is uncertainty for the specific treatments. It was implemented in India as per the WHO and Ministry of Health and Family Welfare (MoHFW) guidelines.[1],[2] More than 1.3 billion people are at risk of contracting the novel Coronavirus (SARS Cov-2) infection in India. Risk profiling was done based on the above guidelines for contact tracing for each positive coronavirus disease-19 (COVID-19) case, and contacts were monitored for 14 days to develop symptoms during their quarantine period. Introduction of SARS CoV-2 from China and after that to the other parts of the world felt the need for contact tracing, as it is an essential tool to control the disease transmission.

In India, a multitude of government agencies and private agencies were involved in contact tracing. Studies regarding the transmission dynamics of SARS CoV-2 depend on contact tracing data for the estimation of basic reproduction numbers (R0) to estimate the number of secondary cases.[3] Contact tracing is used in clinical settings to contain the spread of SARS-CoV-2 transmission efficiently.[4] Besides, it also helps to identify the possible infection source, prioritizes them for testing and isolation, and links exposed individuals. Contact tracing also helped to identify and describe the super spreading events.[5] COVID-19 contact tracing data could also be effectively utilized to understand disease spread heterogeneity, particularly at the individual patient level.[6] Whereas population-level estimates of R0 intend to comprehend the transmission dynamics of SARS Cov-2 as a single broad index, individual-level disparities in the transmission of this virus could propose better understandings to establish preventive interventions.[7]

In general, contact tracing is an extremely effective and robust strategy that should be given adequate importance. The main advantages include that it can identify potentially infected individuals before severe signs and symptoms develop. If conducted swiftly, within the window period, it can prevent further transmission from the secondary cases. Modeling studies have focused on quantifying the importance of presymptomatic infectiousness. Model simulations confirmed that eliminating the ongoing SARS-CoV-2 pandemic is only possible by merging the restrictive social distancing and contact tracing. The precise course of the epidemic chiefly depends on how and when quarantine, isolation, and preventive measures are enforced.[8] Here, we leverage detailed contact tracing data from the western part of Maharashtra and rigorously monitored high-risk contacts until their quarantine completion. Implications of early contact tracing and effective quarantine measures were also observed using parameters for the SARS Cov-2 to contain a novel pathogen in terms of estimations of total contacts who found positive during contact tracing and thus led to the prevention of secondary cases.

  Methods Top

This study included data of contact tracing performed from March 30, 2020, to November 22, 2020, of the patients admitted in the western Maharashtra tertiary care hospital. The author was actively involved in the contact tracing of patients getting admitted to the hospitals. A positive case of COVID-19 was defined as the case in which a nasopharyngeal or oropharyngeal swab specimen was positive for SARS CoV-2 by reverse transcription–polymerase chain reaction (RT-PCR) done in Indian Council of Medical Research recognized laboratory. Contact tracing was done telephonically in all the positive COVID-19 patients, followed by confirmation with the family members. Positive COVID-19 cases were contacted telephonically within 30 min of the confirmation of the COVID-19 status. High-risk and low-risk contacts were earmarked and counseled based on the WHO and NCDC guidelines on contact tracing and home quarantine.

High-risk contacts were “all individuals who are staying in the same house, and any person exposed to symptomatic COVID-19 case, from 2 days before to 14 days after the development of symptoms.” For asymptomatic cases, the period for contact tracing was taken as 2 days before to 14 days after the date sample collection if not isolated earlier. To consider contact as high-risk contact, the duration was taken as >15 min, and the proximity was taken as <1 m, and the use of appropriate personal protective equipment (PPE) during contact was asked. All those contacts who prepared or cleaned the linens, clothes, or utensils of the patient and had direct physical contact with the patient were high-risk contacts. In addition, health-care workers who did the physical examination without adequate PPE (gloves and N95 mask) came in direct contact with body fluids (respiratory tract secretions, blood, vomit, saliva, urine, and feces) of the patient were included in the high-risk contact group.

Low-risk contacts included were all those contacts who were not fitting into the above high-risk contact description. Low-risk contacts did not mean “NO RISK” contact, equal emphasis was given in contact tracing for low-risk contacts as their potential capability to transmit infection. High-risk contacts were quarantined at home or institutional facility for 14 days from the date of last exposure. High-risk contacts were tested and isolated if they became symptomatic during the observation period. Asymptomatic contacts of a confirmed COVID-19 case were tested on the next day till May 18, 2020, and after that, they were tested once between day 5 and day 10 from the date of last exposure as per the revised COVID-19 testing strategy of MoHFW. While quarantined, active monitoring for 14 days after the last exposure was done by contacting them telephonically, and they were given 24 × 7 helpline number of the COVID hospital if they develop any symptoms. High-risk contacts had to remain reachable for active monitoring.

Low-risk contacts were advised for self-monitoring for 14 days after the date of last exposure. They were instructed to use a mask during the 14 day observation period and urged to follow home quarantine strictly. They were also advised to practice physical distancing, cough etiquettes, and hand hygiene in the house. They were asked to remain reachable during the quarantine period. Contacts were followed up for the 14 days telephonically, and in case of development of symptoms, they were isolated and tested.

RT-PCR test was performed throughout the study for confirmation of COVID-19 among contacts. However, the timings of the test have been differed according to the national policies.

Approval of the institutional ethical committee was obtained before starting the study with Information, Education, and Communication (IEC) Serial No. 2020/372. Data were collected and compiled in Microsoft Excel 2019 after doing contact tracing daily, and statistical analysis was done using Statistical Package for the Social Sciences (SPSS) version 20 (IBM Corp. Released 2011. IBM SPSS Statistics for Windows, Version 20.0, Armonk, NY, USA: IBM Corp).

  Results Top

A total of 471 COVID-19 patients were traced after having RT-PCR confirmed positive for novel coronavirus-2019. Out of 471, 104 (22.08%) were females and 367 (77.92%) were males. The mean age of the patients was 35.21(standard deviation 15.43). Out of 471 COVID-19 patients, 269 (57.11%) were symptomatic at the time of admission. Out of 471, 217 (46.07%) were the contacts of confirmed COVID-19 case, of these 217, 125 (57.6%), and 92 (42.4%) were symptomatic. A total of 10 patients succumbed to death out of 471 (2.12%). All COVID-19 patients were asked about their contacts, and based on [Figure 1], testing and management of the contacts were done.

High-risk contacts were identified as per the definition of high-risk contacts. After performing contact tracing, a total of 1943 high-risk contacts and 674 low-risk contacts were determined and followed up daily for the development of symptoms, and high-risk contacts, including low-risk symptomatic contacts, were tested for COVID-19. As described in [Table 1], a total 289 (11.04%) contacts turned positive after follow-up and testing in high-risk contacts and 5 (0.74%) contacts turned symptomatic during the quarantine period. Out of the 471, 217 (46.07) COVID-19 patients were primary contacts of confirmed COVID-19 cases. One hundred and twenty-one (25.69%) patients had a history of domestic travel by bus, by train, or by air.
Figure 1: Algorithm for management of contacts

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Table 1: Details of contact tracing

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A statistically significant association was found between the age group and the total number of primary contacts (P < 0.05). However, the gender of the patient was not found significant (P > 0.05) [Table 2] and [Table 3] depicts that a statistically significant association was found between the gender of the COVID-19 patient and number of positive turned contacts (P < 0.01). [Figure 2] depicts a timeline showing the cumulative number of positive COVID-19 cases, their contacts, and COVID-19 positive turned contacts and COVID-19 cases with a history of domestic or international travel by any mode (by road, by train, or by air).
Figure 2: Timeline showing total primary contacts, contacts turned positive during quarantine, and positive cases with a history of travel

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Table 2: Age and gender-wise distribution of total contacts

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Table 3: Association of gender of COVID-19 patients with positive turned contacts

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  Discussion Top

According to the World Health Organization, “When systematically and timely applied, contact tracing can break the chain of transmission of infectious disease and is thus an essential public health tool for controlling infectious disease outbreaks.”[9] In the COVID-19 perspective, where 80% of patients are asymptomatic or mild, and symptomatic patients are infected on an average for 14 days before they start developing any symptoms.[10] A study conducted by Abraham et al. On COVID-19 testing between January 22 and April 30 described that 35.9% of patients found positive from testing were contacts, which included both symptomatic or asymptomatic cases.[11]

Walrave et al. in their study found that the adoption of a contact tracing App for containment of COVID-19 was a good Initiative to stimulate the uptake of contact tracing. A most significant barrier to using this App was privacy concerns. Hence, while developing and launching a contact tracing app, issues regarding the privacy should be addressed.[12] In India, Arogya Setu App was also launched for the self-assessment, and if the close contacts show any symptoms related to COVID-19, an alarm was given to the individual. It was more comfortable for the government to trace and track the person using their smartphone's GPS location. Reliance Jio also came up with the MyJio Coronavirus Self-diagnostic Tool. It was freely available on the MyJio app, used primarily to support the government's measures to control and mitigate the influence of coronavirus disease in numerous ways. This App provides a handy and straightforward nationwide platform for citizens to proclaim their health parameters and be directed to scientifically mentioned next steps based on their risk status.

One threat to the COVID-19 response in India was the spread of misinformation driven by fear, stigma, and blame. There have been increasing levels of violence against health-care providers and stigmatization of individuals with or suspected of COVID-19. This stigma toward novel coronavirus could hamper the reporting of illness.[13],[14] From April 20, 2020, states began to ease restrictions based on hotspots (cluster containment).[15] The immediate challenge at that time was to keep infections at manageable levels and ensure the ability to test, trace contacts, isolate patients, implement COVID care plans, and disseminate timely information. However, it was observed in states like Karnataka, poor contact tracing was evident as 93% of patients who tested positive were unknown about their contact history.[16]

In our study, heterogeneity in the SARS CoV-2 transmission was seen. There was a positive COVID-19 case in the family of 16 high-risk contacts, all high-risk contacts were staying in overcrowding situation under one roof, and no high-risk contact was found positive. There is evidence that in the early days of the COVID-19 pandemic, outbreaks occurred on the Diamond Princess cruise ship and U.S.S Theodore Roosevelt aircraft carrier. These outbreaks of COVID-19 suggest that SARS CoV-2 spreads quickly in the tighter and closed spaces,[17],[18] whereas on the other hand, in the nuclear family of four, all contacts were found positive. Network analysis methods highlight the individual patient level variation in SARS-CoV-2 transmission.[19] The network analysis method had helped to identify the key individual patients and components, which could help the public health implementers to focus their contact tracing activities.

The basic reproduction number (R0) for Maharashtra was estimated at 1.45 (1.441 and 1.460).[20] Hence, in our study, due to vigorous IEC and contact tracing, around 412 COVID-19 cases were averted. The reality of contact tracing in public health is multifaceted and primarily relies upon the relative timing of events and the management of identified contacts. For contact tracing to be a useful public health tool, most secondary cases should be discovered and isolated before they become transmittable. Subsequently, the time required for the primary case to become infectious, tracing of their contacts needs to be shorter than the incubation period. Extended time scales would allow tertiary cases to be infected and potentially increase the scale of tracing required. Besides, those contacts who are traced need to be efficiently screened for infection and quarantined or isolated to not pose a risk to others.[21]

  Conclusion Top

The benefits of contact tracing depend significantly on adherence to home or institutional quarantine and isolation among contacts, which could be boosted by policy measures such as voluntary out-of-home accommodations and social supports. Notification of RT-PCR-confirmed COVID-19 cases along with the utilization of rapid antigen test kits for the high-risk contacts should be done so that contacts can be quarantined early enough to prevent further transmission of COVID-19. Testing contacts without symptoms can be beneficial by recognizing new cases to trace and potentially refining quarantine adherence.


The authors acknowledge all the residents and health assistants of the Department of Community Medicine, AFMC, who were involved in the contact tracing.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Guidelines for Contact Tracing of Covid-19 Cases in Community Settings. In. Available from: https://ncdc.gov.in/WriteReadData/l892s/5543723831596613278.pdf. [Last accessed on 2020 Nov 21].  Back to cited text no. 1
Contact Tracing in the Context of COVID-19. Available from: https://www.who.int/publications/i/item/contact-tracing-in-the- context-of-covid-19. [Last accessed on 2020 Nov 21].  Back to cited text no. 2
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;26:1341-3.  Back to cited text no. 3
Bilinski A, Mostashari F, Salomon JA. Modeling contact tracing strategies for COVID-19 in the context of relaxed physical distancing measures. JAMA Netw Open 2020;3:e2019217.  Back to cited text no. 4
Bi Q, Wu Y, Mei S, Ye C, Zou X, Zhang Z, et al. Epidemiology and transmission of COVID-19 in 391 cases and 1286 of their close contacts in Shenzhen, China: A retrospective cohort study. Lancet Infect Dis 2020;20:911-9.  Back to cited text no. 5
Martinez-Loran E, Naveja JJ, Bello-Chavolla OY, Contreras-Torres FF. Multinational modeling of SARS-CoV-2 spreading dynamics: Insights on the heterogeneity of COVID-19 transmission and its potential healthcare burden.medRxiv 2020.04.14.20064956; doi: https://doi.org/10.1101/2020.04.14.20064956.  Back to cited text no. 6
Hébert-Dufresne L, Althouse BM, Scarpino SV, Allard A. Beyond R 0: Heterogeneity in Secondary Infections and Probabilistic Epidemic Forecasting Arxiv.Org. Available from: https://github.com/. [Last accessed on 2020 Nov 21].  Back to cited text no. 7
Sarkar K, Khajanchi S, Nieto JJ. Modeling and forecasting the COVID-19 pandemic in India. Chaos Solitons Fractals 2020;139:110049.  Back to cited text no. 8
Organization WH. Establishing Integrated Nationwide Contact Tracing Systems 2 2020. Available from: https://iris.wpro.who.int/handle/10665.1/14553. [Last accessed on 2020 Nov 23].  Back to cited text no. 9
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;172:577-82.  Back to cited text no. 10
Abraham P, Aggarwal N, Babu G, Barani S, Bhargava B, Bhatnagar T, et al. Laboratory surveillance for SARS-CoV-2 in India: Performance of testing & descriptive epidemiology of detected COVID-19, January 22 – April 30, 2020. Indian J Med Res 2020;151:424.  Back to cited text no. 11
Walrave M, Waeterloos C, Ponnet K. Adoption of a contact tracing app for containing COVID-19: A health belief model approach. JMIR Public Health Surveill 2020;6:e20572.  Back to cited text no. 12
Singh R. Psychiatry MS-A Journal of, 2020 Undefined. COVID-19 and Stigma: Social Discrimination towards Frontline Healthcare Providers and COVID-19 Recovered Patients in Nepal. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7293527/. [Last accessed on 2020 Nov 23].  Back to cited text no. 13
Diseases SB-TLI, 2020 Undefined. Stigma during the COVID-19 Pandemic. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7314449/. [Last accessed on 2020 Nov 23].  Back to cited text no. 14
The Lancet. India under COVID-19 lockdown. Lancet 2020;395:1315.  Back to cited text no. 15
India COVID-19. Available from: https://www.isibang.ac.in/~ athreya/incovid19/karframe.php. [Last accessed on 2020 Nov 23].  Back to cited text no. 16
Mizumoto K, Kagaya K, Zaresbski A, Chowell G. Estimating the asymptomatic proportion of coronavirus disease 2019 (COVID-19) cases on board the diamond princess cruise ship, Yokohama, Japan, 2020. Euro Surveill 2020;25:2000180.  Back to cited text no. 17
Kasper MR, Geibe JR, Sears CL, Riegodedios AJ, Luse T, von Thun AM, et al. An Outbreak of Covid-19 on an Aircraft Carrier. N Engl J Med 2020;383:2417-26.  Back to cited text no. 18
Nagarajan K, Muniyandi M, Palani B, Sellappan S. Social network analysis methods for exploring SARS-CoV-2 contact tracing data. BMC Med Res Methodol 2020;20:233.  Back to cited text no. 19
Marimuthu S, Joy M, Malavika B, Nadaraj A, Asirvatham ES, Jeyaseelan L. Modelling of reproduction number for COVID-19 in India and high incidence states. Clin Epidemiol Glob Health. 2021;9:57-61. doi:10.1016/j.cegh.2020.06.012.  Back to cited text no. 20
Keeling MJ, Hollingsworth TD, Read JM. Efficacy of contact tracing for the containment of the 2019 novel coronavirus (COVID-19). J Epidemiol Community Health 2020;74:861-6.  Back to cited text no. 21


  [Figure 1], [Figure 2]

  [Table 1], [Table 2], [Table 3]


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