Screening among Household Contacts of DR-TB Patients

The National TB Elimination Programme (NTEP) follows an integrated algorithm for screening and ruling out active Tuberculosis (TB) among Household Contact persons (HHCs) of Drug-resistant Tuberculosis (DR-TB) patients.

Figure: Integrated Algorithm for Screening and Ruling out Active TB among HHCs of DR-TB Patients; Source: Guidelines for PMDT in India, 2021, p118.

Abbr: MDR/RR-TB: Multidrug-resistant/ Rifampicin-resistant TB; FQ: Fluoroquinolone; h: Isoniazid; R: Rifampicin; DR-TB: Drug-resistant TB; DS-TB: Drug-susceptible TB; TPT: TB Preventive Treatment; CXR: Chest X-ray; TST: Tuberculin Skin Tests; IGRA: Interferon Gamma Release Assay.

Salient Features of the Screening Algorithm

1. Once a DR-TB patient is identified, all HHCs are counselled, screened and evaluated to rule out active TB. 
2. Nucleic Acid Amplification Test (NAAT) will be used up front among contacts with symptoms or abnormal Chest X-ray (CXR) to diagnose TB.

• If the result is Mycobacterium tuberculosis (MTB) detected with no resistance, the treatment for Drug-sensitive TB (DS-TB) is initiated.
• If the result is MTB detected with Isoniazid (H) and/or Rifampicin (R) resistance, manage as per DR-TB guidelines. 
• If the result is MTB not detected, in HHC <5 years of age, assess for TB Preventive Treatment (TPT) and check for any contraindications. 
• If the result is MTB not detected, in HHC >5 years of age with Latent TB Infection (LTBI) test positive or unavailable and CXR is normal or unavailable, check for any contraindications.
• If contraindications to TPT drugs exist, defer TPT and if no contraindication exists, offer TPT regimen as appropriate based on the Drug Susceptibility Testing (DST) pattern of the index patient

Follow-up for active TB as necessary, even for patients who have completed preventive treatment irrespective of TPT offer. 

Footnotes

1. HIV-positive contact: If <10 years of age, any one of current cough, fever, history of contact with TB, reported weight loss, confirmed weight loss >5% since last visit or growth curve flattening or weight for age <-2 Z-scores. Asymptomatic infants, <1 year, with HIV are only treated for LTBI if they are household contacts of a TB patient. TPT or Interferon Gamma Release Assay (IGRA) may identify People Living with HIV (PLHIV) who will benefit most from preventive treatment. CXR may be used in PLHIV on Anti-retroviral Treatment (ART), before starting TPT.
2. Symptomatic HHC: Any one of cough or fever or night sweats or haemoptysis or weight loss or chest pain or shortness of breath or fatigue. Children <5 years should also be free of anorexia, failure to thrive, not eating well, decreased activity or playfulness to be considered asymptomatic.
3. Other key and vulnerable population: Includes silicosis, dialysis, anti-TNF agent treatment, preparation for transplantation or other vulnerable risk groups where testing must precede TPT.
4. Contraindication to TPT: Include acute or chronic hepatitis; peripheral neuropathy (if Isoniazid is used); regular and heavy alcohol consumption. Pregnancy or a previous history of TB are not contraindications.
5. Selection of TPT regimen: Regimen is chosen based on considerations of age, strain (drug-susceptible or otherwise), risk of toxicity, availability and preferences. 
6. CXR may have been carried out early on as part of intensified case finding.

Resources

• Guidelines for Programmatic Management of Drug-resistant Tuberculosis in India, March 2021.
• WHO Consolidated Guidelines on Tuberculosis: Module 1: Prevention: Tuberculosis Preventive Treatment, 2020.
• Latent TB Infection: Updated and Consolidated Guidelines for Programmatic Management, WHO, 2018.

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