Adherence to Isoniazid Preventive Therapy among children living with tuberculosis patients in Delhi, India: An exploratory prospective study.

INH Preventive Therapy (IPT) substantially reduces the risk of incidence of TB disease in pediatric household contacts of TB patients. The National TB Elimination Program (NTEP) of India prescribes a daily regimen of Isoniazid to all under-6 pediatric contacts for 6 months duration. We conducted, this exploratory prospective study (June to Nov' 2020) to assess adherence to IPT and reasons for nonadherence among child contacts of microbiologically confirmed, drug sensitive, non-PLHIV Tuberculosis patients in Delhi, India. The study outcomes included the initiation, adherence and completion of IPT. The caregivers of the child TB contacts were interviewed face to face by the field investigator. The data were entered on EpiData 3.1 and analysed with IBM SPSS 25. The INH adherence was assessed in a total of 86 household child TB contacts. IPT had been initiated in 62 (72.1%) child TB contacts of which 61 (98.4%) received INH within 1 month of starting of ATT-DOTS therapy in the index TB patient of the household. Furthermore, the failure to initiate IPT was reported by 24 (27.9%) child TB contacts. Within the cohort of child TB contacts who were not initiated with IPT, the ATT-DOTS duration in the index-TB patient was ≥5 months in 18 (75%) cases, 1-2 months in 3 (12.5%) cases, and <1 month in also 3 (12.5%) cases. Reasons for non-initiation (n = 24) were reported as refusal by the family in 12 (50%) cases mostly due to concern over side-effects of the drug, while non-provision of the drug by the DOTS provider was also observed in 12 (50%) cases. The mean (SD) INH adherence in the INH initiated cohort was 5.6 (2.0) (n = 62). Reasons for INH non-adherence were attributed to forgetfulness (n = 23, 37.1%), carelessness (n = 24, 38.7%), and intermittent stopping of the medication (n = 17, 27.4%) on the child falling sick, perceived drug side effects, and running out of drug stocks. INH non-adherence defined as at-least two missed INH doses in the previous 7 days was observed in 47 (54.7%) participants (n = 86). On bivariate analysis, none of the household sociodemographic characteristics showed any statistically significant association with the rate of INH non-adherence in the child TB contacts. The findings of the present study indicate the need to periodically assess adherence and persistence to IPT in the child TB contacts as high intermittent missed dosing rates can undermine the effectiveness of IPT in preventing incident disease.