Characteristics of infants exposed to maternal tuberculosis and chemoprophylaxis using 3 months of isoniazid and rifampicin.

BACKGROUND

Although the clinical features of infants with congenital tuberculosis (TB) are well established, the features of infants exposed to TB in utero including those who are non-infected, are not well reported. TB-exposed infants are at risk of developing TB post-delivery, and chemoprophylaxis, usually isoniazid, is therefore recommended. Isoniazid/rifampicin combined is an alternative, but little is known about its effectiveness.

OBJECTIVE

To determine the clinical features of infants exposed to TB in utero and the proportion who develop TB infection and disease despite chemoprophylaxis with a 3-month course of isoniazid/rifampicin.

METHODS

This was a retrospective review of TB-infected women and their infants between 2007 and 2010. Features of mothers and infants at delivery, and follow-up of infants after completion of isoniazid/rifampicin are described.

RESULTS

Eighty-eight infants born to 86 TB-infected women were studied. TB diagnosis was made peri-partum in 24.4% of women, and only 46.2% of those diagnosed ante-partum were on anti-TB treatment for >2 months. Human immunodeficiency virus (HIV) was positive in 97.7% of the TB-infected women and in 74.6% the CD4 count was <200 cells/mm3. Fifty-six (63.6%) infants had a low birthweight (LBW) and 45 (51.2%) were preterm. Mycobacterial culture was positive in four (4.5%) infants (three were also smear-positive) and none was diagnosed with TB on clinical or radiological findings only. At 3-month follow-up, 17 (20.2%) defaulted, and, of 67 who returned, seven (10%) did not return for tuberculin test reading, but one of 60 (1.7%) tested positive. Five infants (7.2%) were HIV PCR-positive at 6 weeks and four of their mothers were on HAART.

CONCLUSION

The majority of TB-exposed infants were born to mothers with TB/HIV co-infection, and a high proportion were pre-term and of low birthweight. Although the high attrition rate made it difficult to assess the effectiveness of chemoprophylaxis with isoniazid/rifampicin, only one of the 60 infants who completed follow-up to 3 months was found to have tuberculous infection.