Background: COVID-19 is an emerging disease caused by highly contagious virus called SARS-CoV-2. It caused an extensive health and economic burden around the globe. There is no proven effective treatment yet, except certain preventive mechanisms. Some studies assessing the effects of different preventive strategies have been published. However, there is no conclusive evidence. Therefore, this study aimed to review evidences related to COVID-19 prevention strategies achieved through contact tracing, screening, quarantine and isolation to determine best practices.

Methods: We conducted a systematic review in accordance with the PRISMA and Cochrane guide lines by searching articles from major medical databases such as: PubMed/Medline, Global Health Database, Embase, CINAHL, Google scholar and clinical trial registries. Non randomized and modeling articles published to date in areas of COVID prevention with contact tracing, screening, quarantine and isolation were included. Two experts screened the articles and assessed risk of bias with ROBINS-I tool and certainty of evidence with GRADE approach. The findings were presented narratively and in tabular form.

Results: We included 22 (9 observational and 13 modeling) studies. The studies consistently reported the benefit of quarantine, contact tracing, screening and isolation in different settings. Model estimates indicated that quarantine of exposed people averted 44% to 81% of incident cases and 31% to 63% of deaths. Quarantine along with others can also halve the reproductive number and reduce the incidence, thus, shorten the epidemic period effectively. Early initiation of quarantine, operating large scale screening, strong contact tracing systems and isolation of cases can effectively reduce the epidemic. However, adhering only to screening and isolation with lower coverage can miss more than 75% of asymptomatic cases, hence, it is not effective.

Conclusion: Quarantine, contact tracing, screening and isolation are effective measures of COVID-19 prevention; particularly when integrated together. In order to be more effective, quarantine should be implemented early and should cover a larger community.

Key words: COVID-19, Quarantine, contact tracing, screening, Isolation