Table 4.

The Effect of Isoniazid Preventive Therapy on Disease Incidence of Children 5 Years of Age or Younger (Household Contacts Who Received Isoniazid Preventive Therapy ≥3 Months)^*

Isoniazid Preventive Therapy	Isoniazid Sensitive		MDR		Mono–Isoniazid Resistant
	Cases/Person-Year	HR (95% CI)	Cases/Person-Year	HR (95% CI)	Cases/Person-Year	HR (95% CI)
No	19/566	Ref	10/145	Ref	3/58	Ref
Yes	1/470	0.06 (0.01 to 0.43)	0/54	0 (0 to infinity)	0/64	0 (0 to infinity)

For definition of abbreviations, see Table 3.

^*Stratified by INH profiles of index cases and adjusted for index case age, recreational drug use, household contact age, sex, bacillus Calmette-Guérin vaccination scar, nutritional status, being a student or not, tuberculosis history, household socioeconomic status, and household residential district

Likelihood ratio test for interaction term = 0.768.