Addressing knowledge gaps and prevention for tuberculosis-infected Indian adults: a vital part of elimination

Abstract Background India plans to eliminate tuberculosis (TB) by 2025, and has identified screening and prevention as key activities. Household contacts (HHCs) of index TB cases are a high-risk population that would benefit from rapid implementation of these strategies. However, best practices for TB prevention and knowledge gaps among HHCs have not been studied. We evaluated TB knowledge and understanding of prevention among tuberculin skin-test (TST) positive HHCs. While extensive information is available in other high-burden settings regarding TB knowledge gaps, identifying how Indian adult contacts view their transmission risk and prevention options may inform novel screening algorithms and education efforts that will be part of the new elimination plan. Methods We approached adult HHC to administer a questionnaire on TB knowledge and understanding of infection. Over 1 year, 100 HHC were enrolled at a tertiary hospital in Pune, India. Results The study population was 61% (n = 61) female, with a mean age of 36.6 years (range 18–67, SD = 12). Education levels were high, with 78 (78%) having at least a high school education, and 23 (24%) had at least some college education. Four (4%) of our participants were HIV-infected. General TB knowledge among HHC was low, with a majority of participants believing that you can get TB from sharing dishes (70%) or touching something that has been coughed on (52%). Understanding of infection was also low, with 42% believing that being skin-test positive means you have disease. To assess readiness for preventive therapy, we asked participants whether they are at a higher risk of progressing to active disease because of their LTBI status. Fifty-four (55%) felt that they are at higher risk. Only 8% had heard of preventive therapy. Conclusion Our TB knowledge survey among HHCs with evidence of recent exposure found that knowledge is poor and families are confused about transmission in the household. It is imperative that the Indian program develop tools and incentives that can be used to educate TB cases and their families on what infected HHCs can do to prevent disease, including preventive therapy

Pregnancy Differentially Impacts Performance of Latent Tuberculosis Diagnostics in a High-Burden Setting

<div><p>Background</p><p>Targeted screening for latent TB infection (LTBI) in vulnerable populations is a recommended TB control strategy. Pregnant women are at high risk for developing TB and likely to access healthcare, making pregnancy an important screening opportunity in developing countries. The sensitivity of the widely-used tuberculin skin test (TST), however, may be reduced during pregnancy.</p><p>Methods</p><p>We performed a cross-sectional study comparing the TST with the QuantiFERON Gold In-tube (QGIT) in 401 HIV-negative women presenting antepartum (n = 154), at delivery (n = 148), or postpartum (n = 99) to a government hospital in Pune, India. A subset of 60 women enrolled during pregnancy was followed longitudinally and received both tests at all three stages of pregnancy.</p><p>Results</p><p>The QGIT returned significantly more positive results than the TST. Of the 401 women in the cross-sectional study, 150 (37%) had a positive QGIT, compared to 59 (14%) for the TST (p<0.005). Forty-nine (12%) did not have their TST read. Of 356 who had both results available, 46 (13%) were concordant positive, 91 (25%) were discordant (12 (3%) TST+/QGIT-; 79 (22%) TST−/QGIT+), and 206 (57%) concordant negative. Comparison by stage of pregnancy revealed that QGIT percent positivity remained stable between antepartum and delivery, unlike TST results (QGIT 31–32% vs TST 11–17%). Median IFN-γ concentration was lower at delivery than in antepartum or postpartum (1.66 vs 2.65 vs 8.99 IU/mL, p = 0.001). During postpartum, both tests had significantly increased positives (QGIT 31% vs 32% vs 52%, p = 0.01; TST 17% vs 11% vs 25%, p<0.005). The same trends were observed in the longitudinal subset.</p><p>Conclusions</p><p>Timing and choice of LTBI test during pregnancy impact results. QGIT was more stable and more closely approximated the LTBI prevalence in India. But pregnancy stage clearly affects both tests, raising important questions about how the complex immune changes brought on by pregnancy may impact LTBI screening.</p></div

Participant characteristics and LTBI test results by time point of screening in Pune, India.

a<p>Missing variables not included in calculations.</p>b<p>Excluding kitchen and bathroom.</p>c<p>Household Food Insecurity Access Scale: Category 1 =  Food Secure, Category 2 =  Mildly Food Insecure, Category 3 =  Moderately Food Insecure, Category 4 =  Severely Food Insecure.</p>d<p>All women enrolled within 24–48 hours of delivery.</p>e<p>TB symptom screen is positive if cough, fever, weight loss, or night sweats are present.</p><p>Abbreviations: HIV indicates human immunodeficiency virus, IPT indicates isoniazid preventive therapy, IQR indicates interquartile range, MDR-TB indicates multi-drug resistant tuberculosis, NA indicates not applicable, TB indicates tuberculosis, TST indicates tuberculin skin test, QGIT indicates QuantiFERON-TB Gold Test In-Tube.</p

Longitudinal comparison of TST and QGIT positivity by stage of pregnancy^a.

<p>QGIT positivity was higher than TST positivity at each stage of pregnancy, but only reached statistical significance at delivery. TST positivity was lowest during delivery and highest in postpartum women. QGIT positivity was also highest in postpartum women. ^aIncludes results for women who had TST and QGIT test results for at least 2 different visits: antepartum/delivery, delivery/postpartum, or antepartum/postpartum. Abbreviations: QGIT =  QuantiFERON TB Gold In-tube Test; TST =  tuberculin skin test.</p

Cross-sectional comparison of TST and QGIT positivity by stage of pregnancy^a.

<p>QGIT positivity was significantly higher than TST positivity at each stage of pregnancy. TST positivity was lowest during delivery and highest in postpartum women. QGIT positivity was stable during antepartum and delivery but was also higher in postpartum women. There was a trend towards a significant difference in TST positivity between antepartum versus delivery (p = 0.17) and antepartum versus postpartum (0.20), and a significant difference between delivery versus postpartum (0.009). There was no significant difference in QGIT positivity between antepartum versus delivery (p = 0.89), but there was a trend towards significance between antepartum versus postpartum (0.11) and a significant difference between delivery and postpartum (p = 0.02). ^aThe number of women who did not return for TST reading was 11 from antenatal, 5 from delivery and 29 from postpartum. Results shown here only include women with both TST and QGIT results. Abbreviations: QGIT =  QuantiFERON TB Gold In-tube Test; TST =  tuberculin skin test.</p