Table 4.

Bacteriological findings in class 3 contacts

Group	Contacts	Total No	No (%) of carriers	No (%) of carriers with pathogenic strain
13	Classmates	286	51 (18)	4 (1)
14	Children at same nursery	220	9 (4)	2 (1)
15	Teachers	44	2 (5)	0
16	Others*	264	31 (12)	7 (3)
All groups	—	814	93 (11.4)	13 (1.6)

^*Neighbours, pupils at same school but not in patient’s class, nurses, and doctors. Contacts sampled only when they had been in close contact with patient during past two weeks before patient became ill.