Table 1.

Aspects of social distancing interventions that can be considered to choose randomised comparisons

Important aspects	Examples
Interventions and their dosing	Physical distance: 1 m (like in France or Italy), 1.5 m (like in Australia), 6 foot (like in US or UK), 3 , 6 m (maximum distance virus can reach upon forceful cough) Closures of spaces where people can meet (decide on whether complete closure or some form of function still allowed): schools (decide on which grades and levels of education and whether any level of physical teaching is allowed in parallel or not); workplace; places of worship; pools; gym; clubs; restaurants; bars; shops (which ones); outdoor areas (e.g. parks, beaches); mass transit; non-essential businesses and services (define how is ‘non-essential’ defined) Cancellation of events where many people could meet: decide on types of events (e.g. movie theatres, music events, carnivals, conferences); decide on limit of people allowed (<10, <50, <1000) Travel restrictions: airport screening or other test before travelling; ban on travel between countries (define which); ban on travel within countries (define range of movement allowed) Quarantine (single person, contacts, large groups, whole buildings, whole towns, whole provinces; cordon sanitaire; define duration and how strictly enforced) Lockdown (all non-essential activities prohibited; outdoor activity permitted; interaction limited to few, repeated social contacts, e.g. ‘lockdown buddy’) Contact tracing (human v. digital; feasibility and usability of digital tools like mobile apps and tracking devices, e.g. electronic bracelets; adherence rates; voluntary v. mandated use) Screening: at building entry, at work, at other facilities (define type, sampling and frequency of screening)
Timing and duration of implementation	Pre-emptively (before any cases have been detected), early in the course of the epidemic (define how early and how timing is decided, based on what features or measurements), late in the course of the epidemic (similarly define) Duration (fixed, until the number of cases/reproductive rate/hospital or ICU occupation reaches a certain threshold)
Sequencing and combination	How different interventions at different doses are sequenced (in what order) and how they are combined
Enforcement of adherence	Advice, intense messaging (how intense and by which stakeholders, with what processes and with what means and media), law with fines, law with strong penalties, law with imprisonment, law with capital punishment
Weaning process	Refers to all of the items discussed above (interventions and dosing, timing, sequencing and combination, enforcement of adherence) but in reverse order, trying to remove restrictions
Measurement of extent of adoption	No measurement, tracking of indicators (decide which indicators)
Use of response indicators/surrogates	Using or not tracking indicators (e.g. number of documented infections, hospitalisations or deaths) to modulate the interventions, add more interventions, remove interventions
Target group choice	Entire population, specific groups defined by age, occupation/workplace, perceived risk factors (e.g. underlying predisposing diseases), or setting (see below)
Setting choice	World-wide, country-wide, town-wide, facility-wide (e.g. nursing homes, hospitals), more precisely localised (if so, decide based on which features)