16.5 Latent tuberculosis infection in household contacts

A household contact is a person who has shared the same enclosed living space as the index case for one or more nights or for frequent or extended daytime periods during 3 months before the start of the current treatment [1] Citation 1. World Health Organization. WHO consolidated guidelines on tuberculosis: Module 1: prevention: tuberculosis preventive treatment. Geneva: World Health Organization. 2020.
https://www.who.int/publications/i/item/who-consolidated-guidelines-on-tuberculosis-module-1-prevention-tuberculosis-preventive-treatment .

16.5.1 Neonates of mothers with active pulmonary tuberculosis

All neonates born to mothers with active PTB should receive treatment for LTBI, after exclusion of active TB, if the mother:

• Has been treated for PTB less than 2 weeks at the time of birth, or
• Has a positive smear microscopy result on a sputum sample collected at birth or close to the time of birth [2] Citation 2. Mittal H, Das S, Faridi MM. Management of newborn infant born to mother suffering from tuberculosis: current recommendations & gaps in knowledge. Indian J Med Res. 2014;140(1):32-39.
  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4181157/ .

Xpert MTB/RIF and Xpert MTB/XDR assays should be performed on a mother's sputum specimen to rule out resistance to rifampicin and isoniazid before starting treatment for LTBI in the neonate.

The recommended regimens are 3HR or 6H. For HIV-exposed neonates receiving nevirapine, only 6H is recommended.

BCG vaccine should be administered just after LTBI treatment completion (not during the treatment).

If a TST is feasible and the regimen chosen is 6H:

• Administer isoniazid for 3 months, then perform a TST.
• If the TST is positive, complete isoniazid monotherapy.
• If the TST is negative, stop isoniazid and administer the BCG vaccine.

Notes:

• A neonate should not be separated from its mother unless severely ill.
• Breastfeeding should continue, and breastfed neonates should receive pyridoxine (vitamin B₆).

16.5.2 Other household contacts 

Children under 5 years

It is not mandatory to perform TST or IGRA prior to LTBI treatment.
All children less than 5 years in contact with a confirmed PTB case and who do not have active TB (for evaluation, see Chapter 4) should receive LTBI treatment, regardless of their HIV and BCG vaccination status.
If LTBI treatment is contra-indicated or in case of parental refusal, monitor the child closely for one year to enable the early detection of active TB.

Children 5 years and older, adolescents and adults

A TST or IGRA should be performed prior to LTBI treatment. If this is not feasible, LTBI treatment may be considered, weighing benefits and risks.

• Children 5 years and over in contact with a confirmed PTB case and who do not have active TB (for evaluation, see Chapter 4) may receive LTBI treatment, regardless of their HIV status.
• Adolescents and adults in contact with a confirmed PTB case and who do not have active TB (no TB symptoms and no abnormality on CXR) may receive LTBI treatment, regardless of their HIV status.

Table 16.3 –  LTBI regimens for household contacts [1] Citation 1. World Health Organization. WHO consolidated guidelines on tuberculosis: Module 1: prevention: tuberculosis preventive treatment. Geneva: World Health Organization. 2020.
https://www.who.int/publications/i/item/who-consolidated-guidelines-on-tuberculosis-module-1-prevention-tuberculosis-preventive-treatment