Table 1.

Sample size required to detect certain antibody conversion rates with 95% CIs at different follow-up periods.

Individuals included and antibody conversion rate		4 weeks between follow-up	8 weeks between follow-up	12 weeks between follow-up
Secondary staff, approximate n=10,620
	Antibody conversion, % (95% CI)	0.4 (0.2-0.6)	0.8 (0.5-1.1)	1.2 (0.9-1.5)
	Converting, n (95% CI)	42 (21-64)	85 (53-117)	127 (96-159)
Secondary students, approximate n=20,400
	Antibody conversion, % (95% CI)	0.4 (0.3-0.5)	0.8 (0.6-1.0)	1.2 (1.0-1.4)
	Converting, n (95% CI)	82 (41-122)	163 (102-224)	245 (184-306)
Primary staff, approximate n=1440
	Antibody conversion, % (95% CI)	0.4 (0.0-0.9)	0.8 (0.1-1.5)	1.2 (0.3-2.1)
	Converting, n (95% CI)	6 (3-9)	12 (7-16)	17 (13-22)
Primary students, approximate n=8460
	Antibody conversion, % (95% CI)	0.4 (0.2-0.6)	0.8 (0.5-1.1)	1.2 (0.8-1.6)
	Converting, n (95% CI)	34 (17-51)	68 (42-93)	102 (76-127)