The COVID-19 pandemic caused many governments to impose policies restricting social interactions . A controlled and persistent release of lockdown measures covers many potential strategies and is subject to extensive scenario analyses . Here, we use an individual-based model (STRIDE) to simulate interactions between 11 million inhabitants of Belgium at different levels including extended household settings, i.e.,``household bubbles". The burden of COVID-19 is impacted by both the intensity and frequency of physical contacts, and therefore, household bubbles have the potential to reduce hospital admissions by 90% . In addition, we find that it is crucial to complete contact tracing 4 days after symptom onset . Assumptions on the susceptibility of children affect the impact of school reopening, though we find that business and leisure-related social mixing patterns have more impact on COVID-19 associated disease burden . An optimal deployment of the mitigation policies under study require timely compliance to physical distancing, testing and self-isolation.