Table 3.

Estimating the required levels of physical distancing (% of reduction required for baseline daily social contacts) to keep the overall attack rates under designated thresholds in different scenarios.

	Attack rate threshold <5%		Attack rate threshold <2%
Contact tracing system	No	Functioning	No	Functioning
With Original strain	50% (39–69%)†	36% (22–56%)	56% (45–52%)	43% (31–46%)
With VOC B.1.1.7	61% (53–68%)	48% (41–60%)	64% (58–71%)	56% (46–64%)
With VOC B.1.167.2	75% (70–80%)	68% (60–75%)	77% (73–81%)	71% (66–77%)

^†The required reduction of daily social contacts for the given thresholds of attack rates. A higher percentage indicated a more strengthened and strict level of physical distancing.