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Table 1 Characteristics of included studies and summary of result

From: Global strategies and effectiveness for COVID-19 prevention through contact tracing, screening, quarantine, and isolation: a systematic review

S.N

Study characteristics and summary report

1

Author/s and title [14]

Matt J Keeling, T Déirdre Hollingsworth, Jonathan M Read. The efficacy of contact tracing for the containment of the 2019 novel coronavirus (COVID-19).

Population size (N)

5802

Country

UK

Setting

Community based

Design

Cross-sectional study

Objectives

To investigate the efficacy of contact tracing for the containment of Covid-19

Study detail

Contact patterns was characterized using a postal and online cross-sectional survey

Interventions

Contact tracing

Results

Assuming that all the contact tracing can be performed rapidly, contact tracing to reduce the basic reproductive ratio from 3.11 to 0.21, enabling the outbreak to be contained. Each new case requires an average of 36 individuals to be traced, with 8.7% of cases having more than 100 close traceable contacts.

2

Author/s and title [15]

Zengyun Hu, Qianqian Cui, Junmei Han. Evaluation and prediction of the COVID-19 variations at different input population and quarantine strategies, a case study in Guangdong province, China

Population size (N)

113460000

Country

China

Setting

Community based

Design

Case study

Objectives

To simulate and predict the disease variations of Guangdong province and to explore the impacts of the input population and quarantine strategies.

Study detail

The impact of input population was evaluated with simulation

Interventions

Quarantine

Results

➢ The simulated peak value of the confirmed cases is 1002 at Feb 10, 2020

➢ The disease will become extinction with peak value of 1397 at May 11, 2020.

➢ The increased numbers of the input population can mainly shorten the disease extinction days and the increased percentages of the exposed individuals

3

Author/s and title [16]

Mingwang S, Zhihang P, Yuming Gu, et al. Assessing the effects of metropolitan-wide quarantine on the spread of COVID-19 in public space and households

Population size (N)

All population in Hubei province, China

Country

China

Setting

Community based

Design

Retrospective

Objectives

To evaluate the impact of the metropolitan-wide quarantine on the trend and transmission route of the SARS-CoV-2 epidemic

Study detail

Data was collected on the number of cumulative confirmed cases

Interventions

Quarantine

Results

In the presence of the quarantine, 100,610 infections, 68,975 confirmed cases and 3252 deaths would have occurred

Quarantine would prevent 79.27% of deaths, 87.08% and 71.84% of infections in public space and households, respectively.

4

Author/s and title [17]

Jean C, Philippe C, et al. Testing the repatriated for SARS-Cov2: should laboratory-based quarantine replace traditional quarantine?

Population size (N)

337

Country

France

Setting

Community based

Design

Cross-sectional

Objectives

To test all passengers for SARS-Cov2 twice in order to reduce anxiety among the population and decision makers

Study detail

The presence of SARS-CoV-19 in asymptomatic carriers were investigated by testing all repatriated patients within the first 24 h of their arrival in France and at day 5, n = 337

Interventions

Laboratory-based quarantine

Results

337 passengers were tested at day 0 and day 5.

Reducing the time scale to a matter of hours with molecular diagnosis is important

5

Author/s and title [18]

Hao-Yuan et al. Contact tracing assessment of COVID-19 transmission dynamics in Taiwan and risk at different exposure periods before and after symptom onset

Population size (N)

100

Country

Taiwan

Setting

Community, health care setting

Design

Prospective case-ascertained study

Objectives

To delineate the transmission dynamics of COVID-19 and evaluate the transmission risk at different exposure window periods before and after symptom onset.

Study detail

Prospective case-ascertained study that enrolled all the initial 100 confirmed cases

Interventions

Contact tracing, all contacts were followed up until 14 days

Results

The overall secondary clinical attack rate was 0.7% (95% CI, 0.4–1.0%).

The attack rate was higher among the 1818 contacts whose exposure to index cases started within 5 days of symptom onset.

The 299 contacts with exclusive presymptomatic exposures were also at risk

High transmissibility of COVID-19 before and immediately after symptom

6

Author/s and title [19]

Guan Wang, Wenhu Chen, Xian Jin, Yi-Peng Chen. Description of COVID-19 cases along with the measures taken on prevention and control in Zhejiang, China

Population size (N)

Population in Hangzhou, Wenzhou, Ningbo, and Taizhou of Zhejiang Province

Country

China

Setting

Community based

Design

Retrospective study

Objectives

To perform a descriptive analysis of clinical characteristics and epidemiological factors of COVID-19 patients and summed up the steps for disease control and treatment in Zhejiang province.

Study detail

Clinical characteristics were carried out on 889 confirmed cases

Interventions

Screening, masks use, prohibiting public gathering, and suspending public transportation

Results

➢ The factor of intimate contact with confirmed cases took up for 39%, 39%, 64%, and 44% in Hangzhou, Wenzhou, Ningbo, and Taizhou, respectively, which was the leading cause of COVID-19.

➢ Preventing contact with confirmed cases could largely avoid the disease to happen.

7

Author/s and title [20]

Siukan Law, et al. Severe acute respiratory syndrome (SARS) and coronavirus disease-2019 (COVID-19): from causes to preventions in Hong Kong

Population size (N)

General population in Hong Kong

Country

Hong Kong

Setting

Community based

Design

Retrospective

Objectives

To discuss the current understanding of COVID-19 and compares with the outbreak of SARS-CoV-2 in 2003 of Hong Kong

Study detail

A retrospective study was performed to summarize the current knowledge of COVID-19

Interventions

Cases and contact handling and prevention activities on healthcare workers and community

Results

Personal hygiene and protection are the most important for preventing the spread of COVID-19 such as wearing a mask and washing hands as well as reducing social contact including avoiding crowds and working at home.

8

Author/s and title [21]

Vincent C. et al. Escalating infection control response to the rapidly evolving epidemiology of the coronavirus disease 2019 (COVID-19) due to SARS-CoV-2 in Hong Kong

Population size (N)

Population in Hong Kong

Country

Hong Kong

Setting

Health care setting

Design

Case-control study, HCWs with unprotected exposure

Objectives

To describe the infection control preparedness measures undertaken for coronavirus disease (COVID-19)

Study detail

A bundled approach of active and enhanced laboratory surveillance, early airborne infection isolation, rapid molecular diagnostic testing, and contact tracing for healthcare workers (HCWs) with unprotected exposure in the hospitals was implemented

Interventions

Isolation, rapid molecular diagnostic testing, and contact tracing

Results

Vigilance in hand hygiene practice, wearing of surgical masks in the hospital, and appropriate use of PPE in patient care are the key infection control measures

9

Author/s and title [22]

Yansen Bai; et al. SARS-CoV-2 infection in health care workers: a retrospective analysis and model study

Population size (N)

HCWs in the department of neurosurgery of union hospital of Wuhan, N = 171

Country

China

Setting

Health care setting

Design

Single center of case-control series

Objectives

➢ To investigate the risk factors to COVID-19.

Study detail

A single-center study was carried out in the Department of Neurosurgery,

Interventions

Quarantine and isolation

Results

By reducing the average contact rate per HCW by a 1.35 factor and susceptibility by a 1.40 factor, we can avoid an outbreak of the basic case among HCWs.

10

Author/s and title [23]

Xiuli L. et al. Modelling the situation of COVID-19 and effects of different containment strategies in China with dynamic differential equations and parameters estimation

Population size (N)

General population in china

Country

China

Setting

Community based

Design

QSEIR modeling

Objectives

To estimate the dynamic evolution mechanism of the epidemic in China, to find when the epidemic will end and how this result depends on different containment strategies.

Study detail

A quantitative prediction of future epidemic developments based on different containment strategies with the QSEIR model has been made by setting January 23, 2020, as the beginning date of the simulation (5000)

Interventions

Quarantine

Results

Quarantine measures are the most effective containment strategy to control the epidemic.

11

Author/s and title [24]

Adam J. et al. Effectiveness of isolation, testing, contact tracing and physical distancing on reducing transmission of SARS-CoV-2 in different settings: modelling study

Population size (N)

General population in UK

Country

UK

Setting

Community based

Design

Mathematical modeling

Objectives

To understand what combination of measures including novel digital tracing approaches and less intensive physical distancing may be required to reduce transmission.

Study detail

Using a model of individual-level transmission stratified by setting (household, work, school, other) based on BBC Pandemic data from 40,162 UK participants

Interventions

Isolation, testing, contact tracing, and physical distancing

Results

➢ Combined isolation and tracing strategies would reduce transmission more than mass testing or self-isolation alone (50–60% compared to 2–30%).

12

Author/s and title [25]

Biao Tang, et al. Estimation of the transmission risk of the 2019-nCoV and its implication for public health interventions

Population size (N)

Population in China

Country

China

Setting

Community based, health care

Design

Mathematical Modeling, R0 = 6.47

Objectives

To estimate the basic reproduction number by means of mathematical modeling

Study detail

A deterministic compartmental model was devised based on the clinical progression of the disease, epidemiological status of the individuals, and intervention measures.

Interventions

Contact tracing, quarantine and isolation

Results

➢ The estimations based on likelihood and model analysis show that the control reproduction number may be as high as 6.47 (95% CI, 5.71–7.23).

➢ Interventions, such as intensive contact tracing followed by quarantine and isolation, can effectively reduce the control reproduction number

➢ With travel restriction, the number of infected individuals in seven days will decrease by 91.14% in Beijing, compared with the scenario of no travel restriction.

13

Author/s and title [26]

Rocklöv J, et al. COVID-19 outbreak on the Diamond Princess cruise ship: estimating the epidemic potential and effectiveness of public health countermeasures

Population size (N)

Population in cruise ship

Country

Japan

Setting

Community based

Design

SEIR modeling

Objectives

To study the empirical data of COVID-19 confirmed infections on the Cruise ship Diamond Princess, to estimate the R0.

Study detail

SEIR modeling was used on data confirmed cases on the cruise ship

Interventions

Isolation, quarantine, and removal interventions

Results

➢ Based on the modeled initial of 14.8, without any interventions within period of 21 January to 19 February, 2020, out of the 3700 (79%) would have been infected.

➢ The R0 was 14.8 initially and then declined to a stable 1.78 after the quarantine, and removal interventions were initiated.

➢ Isolation and quarantine therefore prevented 2307 cases

14

Author/s and title [27]

Zhao S, Chen H. Modeling the epidemic dynamics and control of COVID-19 outbreak in China

Population size (N)

Population in china (excluding Hubei)

Country

China

Setting

Community based

Design

Mathematical modeling, SUQC

Objectives

To characterize the dynamics of COVID-19

Study detail

SUQC model is applied to the daily released data

Interventions

Quarantine

Results

➢ The confirmation rate of Wuhan is 0.0643, substantially lower than that of Hubei excluding Wuhan (0.1914) and that of China excluding Hubei (0.2189), but it jumps to 0.3229 after February 12 when clinical evidence was adopted

➢ The number of unquarantined infected cases in Wuhan on February 12, 2020, is estimated to be 3509 and declines to 334 on February 21, 2020.

15

Author/s and title [28]

Neil M et al. Impact of non-pharmaceutical interventions (NPIs) to reduce COVID-19 mortality and healthcare demand

Population size (N)

Population in the UK and USA

Country

UK and USA

Setting

Community based

Design

Mathematical modeling study

Objectives

To assess the potential role of a number of public health measures—so-called non-pharmaceutical interventions (NPIs)

Study detail

The effect of non-pharmacological measures were measured

Interventions

Non-pharmaceutical interventions

Results

➢ To reduce R0 to close to 1 or below, a combination of case isolation, social distancing, quarantine, or school and university closure are required

➢ Optimal mitigation policies reduce healthcare demand by 2/3 and deaths by half.

16

Author/s and title [29]

Zifeng Yang, et al. Modified SEIR and AI prediction of the epidemics trend of COVID-19 in China under public health interventions

Population size (N)

Population in china

Country

China

Setting

Community based

Design

Mathematical Modeling, SEIR and an artificial intelligence (AI) approach

Objectives

A modified susceptible-exposed-infected-removed (SEIR) epidemiological model was used that incorporates the domestic migration data before and after January 23 and the most recent COVID-19 epidemiological data to predict the epidemic progression.

Study detail

SEIR model was used epidemiological data based on daily COVID-19 outbreak numbers reported by the National Health Commission of China

Interventions

Quarantine, strict controls on travel and extensive monitoring of suspected cases

Results

➢ A 5-day delay in implementation would have increased epidemic size three-fold.

➢ Where the interventions to be introduced 5 days earlier than they had been, the number of cases nationwide would have been 40,991

➢ Lifting the Hubei quarantine would lead to a second epidemic peak in Hubei province in mid-March and extend the epidemic to late April

17

Author/s and title [30]

Peak, Corey M., et al. Modeling the comparative impact of individual quarantine vs. active monitoring of contacts for the mitigation of COVID-19 (2020)

Population size (N)

2000

Country

USA

Setting

General population

Design

Stochastic branching model

Objectives

To estimate the comparative efficacy of these interventions to control COVID-19 using a stochastic branching model

Study detail

A branching model was fitted for comparing two sets of reported parameters for the dynamics of the disease with a mean serial interval of 4.8 days and 7.5 days

Interventions

Individual quarantine vs. active monitoring of contacts

Results

➢ If social distancing reduces the reproductive number to 1.25 (e.g., 50% of person-to-person contact is removed in a setting where R0 = 2.5), active monitoring of 50% of contacts can result in overall outbreak control (i.e., Re < 1).

➢ Tracing 10%, 50%, or 90% of contacts on top of social distancing resulted in a median reduction in Re of 3.2%, 15%, and 33%, respectively, for active monitoring and 5.8%, 32%, and 66%, for individual quarantine.

➢ Individual quarantine may contain an outbreak of COVID-19 with a short serial interval (4.8 days) only in settings with high intervention performance where at least three-quarters of infected contacts are individually quarantined.

18

Author/s and title [31]

Biao Tang et al. The effectiveness of quarantine and isolation determine the trend of the COVID-19 epidemics in the final phase of the current outbreak in China

Population size (N)

General population in china

Country

China

Setting

Community based

Design

dynamic model

Objectives

To devise a dynamic model with suspected compartment incorporating prevention and control strategies to predict the trend of the COVID-19 epidemics based on multiple data sources and assess the efficacy of control strategies

Study detail

data of laboratory-confirmed COVID-19 cases in China was obtained from the “National Health Commission” of the People’s Republic of China and the Hubei’s “Health Commission

Interventions

Quarantine and isolation

Results

The trend of the epidemics mainly depends on quarantined and suspected cases.

Most infected cases have been quarantined or put in suspected class, which has been ignored in existing models.

The strong measures implemented have reduced the effective reproduction number. These interventions may take a longer time to be effective as the second and third generations of infected people are exposed in succession.

19

Author/s and title [32]

Can Hou, et al. The effectiveness of quarantine of Wuhan city against the corona virus disease 2019 (COVID-19): A well-mixed SEIR model analysis

Population size (N)

11081000

Country

China

Setting

Community based

Design

A well-mixed SEIR modeling

Objectives

to explore the effectiveness of the quarantine of Wuhan city against the epidemic

Study detail

The data of confirmed and suspected cases of COVID-19 acute respiratory disease reported by cities and provinces in mainland China were obtained

Interventions

Quarantine

Results

Reducing the contact rate of latent individuals after quarantine and isolation can effectively reduce the number of individuals infected with COVID-19 and delay the peak time.

20

Author/s and title [33]

Joel Hellewell, et al. Feasibility of controlling COVID-19 outbreaks by isolation of cases and contacts

Population size (N)

100

Country

UK

Setting

Community based

Design

Stochastic transmission modeling

Objectives

To assess if isolation and contact tracing are able to control onwards transmission from imported cases of COVID-19

Study detail

A mathematical model was employed to assess the feasibility of contact tracing and case isolation to control outbreaks of using simulated new outbreaks starting from 5, 20, or 40 introduced cases.

Interventions

Contact tracing and case isolation

Results

When R0 was 2.5 or 3.5, the probability of controlling an outbreak decreased with the number of initial cases

The majority of scenarios with an R0 of 1.5 were controllable with less than 50% of contacts successfully traced.

To control the majority of outbreaks, for R0 of 2.5, more than 70% of contacts had to be traced, and for an R0 of 3.5, more than 90% of contacts had to be traced.

The delay between symptom onset and isolation had the largest role in determining whether an outbreak was controllable when R0 was 1.5.

For R0 values of 2.5 or 3.5, if there were 40 initial cases, contact tracing and isolation were only potentially feasible when less than 1% of transmission occurred before symptom onset.

Contact tracing and isolation might not contain outbreaks of COVID-19 unless very high levels of contact tracing are achieved.

21

Author/s and title [34]

Katelyn Gostic, et al. Estimated effectiveness of symptom and risk screening to prevent the spread of COVID-19.

Population size (N)

30

Country

USA

Setting

Community based

Design

Mathematical modeling

Objectives

To estimate the impact of different screening programs given current knowledge of key COVID-19 life history and epidemiological parameters

Study detail

 

Interventions

Screening

Results

In a growing epidemic, even under the best-case assumptions, with just one infection in twenty being subclinical and all travelers passing through departure and arrival screening, the median fraction of infected travelers detected is only 0.30

In a stable epidemic, under the middle-case assumption that 25% of cases are subclinical, it is estimated that arrival screening alone would detect roughly one-third of infected travelers and that a combination of arrival and departure screening would detect nearly half of infected travelers

Under best-case assumptions, screening will miss more than half of infected people

22

Author/s and title [35]

Mirjam E. et al. Isolation and contact tracing can tip the scale to containment of COVID-19 in populations with social distancing

Population size (N)

100

Country

Netherlands

Setting

Community based

Design

stochastic transmission model

Objectives

To evaluate under which conditions containment could be achieved with combinations of social distancing, isolation and contact tracing

Study detail

Stochastic transmission model-based analyses of the impact of isolation and contact tracing in a setting with various levels of social distancing measures, using varying levels of the effectiveness and timeliness of contact tracing was provided, n = 100.

Interventions

Isolation and contact tracing in populations with social distancing

Results

If the proportion of asymptomatic infections is larger than 30%, contact tracing and isolation cannot achieve containment for an R0 of 2.5

To achieve containment by social distancing requires a reduction of numbers of non-household contacts by around 90%.

Social distancing reduces non-household contacts only by 50%, tracing and isolation also of non-household contacts is needed for containment.