Non-pharmaceutical interventions and risk of COVID-19 infection: survey of U.K. public from November 2020 – May 2021

Table 1 Analyses, study populations and case definitions

Analysis	Cases^a	Comparison group	Time window for NPIs
Primary	Probable COVID-19	Study population excluding cases and those meeting our broader ‘Suspected COVID-19’ definition	2 weeks before questionnaire completion (cases and comparison)
Sensitivity 1	Probable COVID-19, excluding those who reported receiving one or more COVID-19 vaccine doses prior to completing the questionnaire	Study population excluding cases, ‘Suspected COVID-19’, and participants who reported receiving one or more COVID-19 vaccine doses prior to completing the questionnaire	2 weeks before questionnaire completion (cases and comparison)
Sensitivity 2	Suspected COVID-19	Those not meeting case definition	2 weeks before questionnaire completion (cases and comparison)
Sensitivity 3	Symptomatic COVID-19	Those not meeting case definition	2 weeks before illness (cases) and 2 weeks before questionnaire completion (comparison group)
Sensitivity 4	Any acute RTI lasting 3 days or more	Those not meeting case definition	2 weeks before illness (cases) and 2 weeks before questionnaire completion (comparison group)

^aProbable COVID-19: Positive COVID-19 ‘nose or throat swab’ test AND/OR self-reported respiratory illness (of 3 or more days) occurring during the pandemic period that was associated with fever and loss of smell and/or taste [10]
Suspected COVID-19: Positive COVID-19 ‘nose or throat swab’ test AND/OR self-reported respiratory illness (of 3 or more days) occurring during the pandemic period that was associated with loss or smell and/or taste OR fever and cough OR three or more of: fever, cough, fatigue, headache, myalgia, sore throat, runny or blocked nose, shortness of breath, nausea or vomiting, diarrhoea [11]
Symptomatic COVID-19: Those meeting the criteria for Susptected COVID-19, but excluding those with a positive nose or throat swab who did not report having a respiratory illness lasting 3 days or more

ISSN: 1471-2458