Table 1.

Periods of data collection for KCL CHECK to week 18 (April – Aug 2020)

	Timepoint
Data collection period	P0 (Baseline)	P1	P2	P3	P4	P5	P6	P7	P8
Week of study	1–3	3–4	5–6	7–8	9–10	11–12	13–14	15–16	17–18
Month	April	May		June			July		Aug
Long survey • "In the last two months"	x				x				x
Short survey • "In the last two weeks"		x	x	x		x	x	x
Antibody test						x