RESUMEN
OBJECTIVES: This study aimed to investigate (1) definitions of self-isolation used during the COVID-19 pandemic; (2) measures used to quantify adherence and their reliability, validity, and acceptability; (3) rates of self-isolation adherence; and (4) factors associated with adherence. STUDY DESIGN: This was a systematic review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Synthesis Without Meta-analysis (PRISMA) guidelines (PROSPERO record CRD42022377820). METHODS: MEDLINE, PsycINFO, Embase, Web of Science, PsyArXiv, medRxiv, and grey literature sources were searched (1 January 2020 to 13 December 2022) using terms related to COVID-19, isolation, and adherence. Studies were included if they contained original, quantitative data of self-isolation adherence during the COVID-19 pandemic. We extracted definitions of self-isolation, measures used to quantify adherence, adherence rates, and factors associated with adherence. RESULTS: We included 45 studies. Self-isolation was inconsistently defined. Four studies did not use self-report measures. Of 41 studies using self-report, one reported reliability; another gave indirect evidence for the lack of validity of the measure. Rates of adherence to self-isolation for studies with only some concerns of bias were 51%-86% for COVID-19 cases, 78%-94% for contacts, and 16% for people with COVID-19-like symptoms. There was little evidence that self-isolation adherence was associated with sociodemographic or psychological factors. CONCLUSIONS: There was no consensus in defining, operationalising, or measuring self-isolation, resulting in significant risk of bias in included studies. Future definitions of self-isolation should state behaviours to be enacted and duration. People recommended to self-isolate should be given support. Public health campaigns should aim to increase perceived effectiveness of self-isolation and promote accurate information about susceptibility to infection.