Table 1.

Carriage rate of Neisseria meningitidis during first week of term, 1997

Date	No of students		% carriage rate (95% CI)
	Swabbed	Positive for N meningitidis
30 September	825	57	6.9 (5.3 to 8.9)
1 October	669	75	11.2 (8.9 to 13.6)
2 October	691	131	19.0 (16.0 to 21.9)
3 October	268	62	23.1 (18.1 to 28.2)

χ² for linear trend = 74. 

P<0.0001.