Risk factors for TB infection and disease in young childhood contacts in Malawi

The utility of a modified WHO TB screening tool among children at a Botswana child welfare clinic

Background

In high TB/HIV settings, the increased risk for TB amongst children exposed to HIV has been established through biomedical tests. Screening HIV exposed children for TB can improve early childhood TB detection and treatment.

Objective

This study assessed the utility of a modified World Health Organization (WHO) tool by including HIV variables, to determine TB exposure amongst HIV exposed children presenting to a “Well Child” Clinic (CWC).

Methods

Clinical data were obtained from medical records and/or from the caregivers of children presenting to CWC. Data was analyzed to explore factors associated with positive screening for TB, including being exposed to HIV and current HIV status.

Results

Five percent (55/1100) screened reported a close TB contact and 21% (n=231) had positive TB symptom screen. History of close TB contact was a risk factor for positive screening for TB symptoms (OR 1.89 CI 1.05–3.4) while being HIV negative was protective (OR 0.3, Cl 0.19–0.62). HIV exposure was associated with increased risk of TB exposure (OR 2.9 CI 1.61–5.19).

Conclusion

Integrating HIV variables in the existing WHO screening tool for childhood TB can be useful in early detection and treatment of TB in HIV exposed children in resource limited settings.

Prevalence of tuberculosis infection and its relationship to stunting in children (under five years) household contact with new tuberculosis cases

BACKGROUND

Children who inhabit the same house with tuberculosis (TB) patients are at high risk for infection and illness with TB. Nutritional status (stunting) in children is related to the child's ability to withstand MTB (Mycobacterium Tuberculosis). This study aims to estimated the prevalence of tuberculosis infection and its relationship to stunting in children (under five years) with household contact (HHC) with new TB cases.

METHODS

A cross-sectional design was implemented. Conducted in July 2018-April 2019 at 13 Public Health Center in Makassar City. The sample size was calculated using one sample situation-about precision formula. Samples were children under five who had contact with new diagnosed TB cases. Tuberculosis infection was measured by TST (tuberculin skin test). Logistic regression with causal model to examine TB infection relationship with stunting and covariate variable, analyzed using Stata/MP 13.0 software.

RESULTS

One hundred twenty-six (126) eligible children. Prevalence of tuberculosis infection was 38.10%. Frequency of stunted was 31 children (24.60%). Stunted nutritional status (aPR): 2.36, 95% CI 1.60-3.44), boys (aPR: 1.47, 95% CI 0.96-2.25), not getting BCG immunization (aPR: 1.58, 95%) CI 0.89-2.82), and high contact intensity (aPR: 2.62, 95% CI 1.10-6.22) best predicted the tuberculosis infection in children with TB case household contacts with a model contribution of 64%.

CONCLUSION

Stunted nutritional status (moderate and severe), boys, not getting BCG immunization, and high contact intensity are the determinants of TB infection transmission in children HHC with TB. Children under five years of age who have close contact with TB cases should be targeted for priority interventions to prevent the transmission of TB infection and progressing to TB cases.

Evaluation of clinical and laboratory characteristics of childhood tuberculosis

Aim:

Tuberculosis is one of the oldest and most contagious diseases of human history. One- quarter of the world’s population is infected with the tuberculosis bacillus. Childhood tuberculosis does not have a standard clinical and radiologic description. Herein, we aimed to evaluate the clinical, laboratory, and radiologic findings of childhood tuberculosis.

Material and Methods:

The medical records of 216 patients hospitalized and treated with a diagnosis of TB between January 2015 and July 2019 in the Division of Pediatric Infectious Diseases in our hospital, were examined retrospectively.

Results:

One hundred twenty-nine (59.7%) of 216 patients who were diagnosed as having TB were female and 87 (40.3%) were male. The age distribution of the patients was 12.3 (range, 0.33–18) years. One hundred sixty-nine patients (78.2%) had pulmonary, 34 (15.7%) had extrapulmonary, 13 had (6%) both pulmonary and extrapulmonary. One hundred forty-three (66.2%) patients had tuberculin skin test positivity. Acid-resistant bacteria were observed in 46 (21.3%) body fluid samples, and culture positivity was observed in 42 (19.4%) samples. The association of pulmonary tuberculosis and extrapulmonary tuberculosis was found with a higher rate in individuals who lived on minimum wage and in patients who had growth and developmental retardation (p=0.001, p<0.001). The hospitalization time was longer in these patients (p=0.027). The hemoglobin and sodium levels were significantly lower in patients who had extrapulmonary tuberculosis (p=0.044, p=0.002).

Conclusion:

Although the diagnosis of childhood tuberculosis is difficult due to the nonspecific signs and symptoms, it is a preventable and treatable disease.

Tuberculosis disease and infection among household contacts of bacteriologically confirmed and non-confirmed tuberculosis patients

OBJECTIVE

To compare the prevalence of tuberculosis infection and disease in household contacts of patients with bacteriologically confirmed tuberculosis disease and contacts of non-bacteriologically confirmed disease in western Kenya.

METHODS

We enrolled newly diagnosed index patients and their household contacts from March 2014 to June 2016. All contacts were evaluated with a symptom questionnaire, tuberculin skin test (TST) and HIV test. Clinical evaluation and sputum testing were performed for those with symptoms, positive TST result or HIV infection.

RESULTS

We enrolled 1155 contacts of 330 index patients with bacteriologically confirmed tuberculosis and 192 contacts of 55 index patients with non-bacteriologically confirmed tuberculosis. 3.5% of contacts of patients with bacteriologically confirmed tuberculosis were diagnosed with tuberculosis, whereas no contacts of index patients with non-bacteriologically confirmed tuberculosis were. Of those diagnosed with tuberculosis disease, 58.5% reported symptoms, 34.1% reported no symptoms but had positive TST results, and 7.3% had neither symptoms nor positive TST but were HIV-positive. Among 872 contacts with a TST result, 50.9% of contacts of index patients with bacteriologically confirmed tuberculosis and 41.0% of contacts of index patients with non-bacteriologically confirmed tuberculosis had a positive result (prevalence ratio = 1.16, 95% confidence interval 0.92-1.48).

CONCLUSION

In a high-burden setting, tuberculosis disease was more prevalent among contacts of patients with bacteriologically confirmed tuberculosis than contacts of patients with non-bacteriologically confirmed disease. TST was feasible to perform and helped to detect cases that would have been missed had only symptomatic contacts been evaluated.

Association of Low Sputum Smear Positivity among Tuberculosis Patients with Interferon-Gamma Release Assay Outcomes of Close Contacts in Japan

Risk prediction and response measures may differ in tuberculosis (TB) patients with low sputum smear positivity for acid-fast bacillus (AFB) compared to those who are smear negative. However, previous studies using the tuberculin skin test (TST) did not show that differences in measures are important. This study compared results of interferon-gamma release assays (IGRA) between contacts of pulmonary TB patients with AFB smear positivity and those with smear negativity using QuantiFERON®-TB Gold In-Tube (QFT) assays. Close contacts of TB patients with culture-confirmed infections between April 2010 and December 2012 in Ibaraki, Japan, were enrolled, and 439 Japanese contacts of 129 index TB patients were examined. Adjusted odds ratios of QFT in contacts were 0.68 (95% confidence interval: 0.17-2.8) for AFB scanty patients, 1.12 (0.45-2.8) for AFB 1+, 1.20 (0.48-3.0) for AFB 2+, and 4.96 (1.9-12.9) for AFB 3+, compared to those who were smear negative. Differences in IGRA positivity were not significant between close contacts of TB patients with low positive and negative smears.

Tuberculosis Burden among Household Pediatric Contacts of Adult Tuberculosis Patients

OBJECTIVES

To find out the prevalence of latent tuberculosis (TB) infection and TB disease among pediatric household contacts of adult drug resistant (MDR) and drug susceptible (DS) TB patients and to identify the risk factors for occurrence of TB infection in the contacts.

METHODS

Pediatric household contacts (less than 15 y age) of adult TB patients (both MDR and DS) were included in the study. They were categorized as latent TB infection (LTBI), TB disease and TB exposed based on the results of tuberculin skin testing (TST), clinical examination and chest X-ray. Various factors (age, gender, socioeconomic status, BCG immunization etc.) were evaluated to assess their association with TB transmission.

RESULTS

A total of 271 household contacts were included in the study. Prevalence of LTBI was 20.3% (31% in MDR TB group and 14% in DS TB group); difference was significant (p value = 0.0018). TB disease was seen in 3 subjects in DS group while none in MDR group developed TB disease. Lower socioeconomic status was significantly associated with risk of TB infection in MDR group (p value =0.0027). In DS TB group, male gender, BCG non-immunization was significantly associated with risk of developing TB (p value 0.0068 and 0.0167 respectively).

CONCLUSIONS

Prevalence of latent TB infection was found to be high in household pediatric contacts especially in contacts of MDR TB patients. Risk factors identified for occurrence of TB included lower socioeconomic status, BCG non-immunization and male gender. The study focuses on the importance of contact screening and the need for its implementation in TB control programs.

Tuberculosis contact-tracing among Syrian refugee populations: lessons from Jordan

BACKGROUND

In response to the influx of displaced Syrians since 2011, the Jordanian National Tuberculosis Program (NTP) implemented a specific Tuberculosis (TB) reduction strategy, including contact-tracing (CT). Contacts of all refugees diagnosed with pulmonary TB (PTB) were registered by the International Organization for Migration and screened for active & latent TB infection (LTBI) in 6 NTP centres.The objectives of this study were to assess prevalence of active TB and LTBI, risk factors for LTBI as well as program performance.

METHODS

We performed a retrospective study among contacts (N = 481) of all PTB cases diagnosed between March 2011 and May 2014 (N = 76). CT was performed using verbal screening of TB-related symptoms, tuberculin skin test (TST) and chest X-ray.

RESULTS

LTBI was diagnosed in 24.1% of contacts tested with TST while active TB was diagnosed in 2.1% of contacts. Main risk factors for positive TST included smear-positive index case (IC) (OR: 6.33) and previous TB infection in the family (OR: 4.94). Among children, the risk of LTBI was higher when their IC was a care-giving female (OR: 2.83). Prevalence of active TB was two times higher in children under five (U5 s) (5.3%) compared to adults (2.5%).

CONCLUSION

We found a high prevalence of active TB and LTBI among contacts of PTB cases in the Syrian refugee population, emphasizing the urgent need for host countries to implement CT strategies for refugees. Our results underscore the vulnerability of U5s and contacts of smear-positive IC highlighting the need for specific actions focusing on those groups.

TST positivity in household contacts of tuberculosis patients: a case-contact study in Malawi

BACKGROUND

Screening household contacts of active tuberculosis (TB) patients is recommended for TB control. Due to resource constraints this rarely occurs in lower income countries. Demographic and clinical features of index cases may influence the likelihood of onwards TB transmission. It has also been proposed that accumulation of intracellular lipid bodies within M. tuberculosis cells may also enhance bacterial transmissibility. This study explored whether clinical and bacteriological observations recorded at baseline in TB cases in Malawi could help identify those with the highest risk of onwards transmission, to prioritise contact tracing.

METHODS

In this case-contact study, data on clinical presentation, sputum bacterial load and the percentage of lipid body positive acid-fast bacilli (%LB + AFB) on sputum smears were recorded in adults with sputum smear and culture positive pulmonary TB before initiation of therapy. The Tuberculin Skin Test (TST) was used to detect infection with M. tuberculosis amongst household contacts under the age of 15 years. TST positivity of the child contacts was related to characteristics of the index case.

RESULTS

Thirty four index cases brought 56 contacts (median: 1, range: 1-4 contacts each). 37 (66%) of contacts had a positive TST. Cavities or a high percentage of lung affected on index patient CXRs were associated with TST positivity. Multivariate analysis of non-radiological factors showed that male sex, HIV-negative status and raised peripheral blood white blood count (WBC) in index patients were also independent risk factors of TST positivity. Lower %LB + AFB counts were associated with TST positivity on univariate analysis only.

CONCLUSION

TST positivity is common amongst household contacts of sputum smear positive adult TB patients in Malawi. Contact tracing in this high risk population could be guided by prioritising index cases with CXR cavities and extensive radiological disease or, in the absence of CXRs, those who are HIV-negative with a raised WBC.

A review of tuberculosis contact investigations in the poor urban areas of Manila, The Philippines

Setting: Socio-economically underprivileged areas in the Philippines. Objective: To review the implementation of tuberculosis (TB) contact investigations in the urban poor areas of Manila and Quezon City. Design: A descriptive cross-sectional study based on a review of data from household contact registries in local government unit (LGU) and non-government organisation (NGO) facilities during January-December 2012 in Manila and Quezon City. Free discussion sessions were also conducted among health-care workers. Results: Of 6161 children and adult household contacts listed in the LGUs and 1893 in the NGOs, 17% (n = 1086) in the LGUs and 95% (n = 1800) in the NGOs were evaluated. The yield of clinically diagnosed TB among children aged <15 years was 10.2% (127/1245) in the LGUs and 8.4% (63/752) in the NGOs. The yield of isoniazid preventive therapy (IPT) for those aged <5 years was 23.1% (124/537) in the LGUs and 28.0% (78/279) in the NGOs. The NGOs produced a high yield of IPT due to a better logistical system that ensured the availability of supplies and systematic home visits. Conclusion: Screening of household contacts in poor urban areas appears to be effective; it increased the number of children aged <15 years eligible for IPT and should be expanded as an intervention strategy for TB control in the Philippines.

Knowledge and perception about tuberculosis among children attending primary school in Ntcheu District, Malawi

BACKGROUND

Knowledge and perceptions about tuberculosis (TB) can influence care-seeking behavior and adherence to treatment. Previous studies in Malawi were conducted to assess knowledge and attitudes regarding TB in adults, with limited data on knowledge in children.

OBJECTIVES

This study assessed knowledge and perceptions about TB in children aged 10-14 years attending primary school in Ntcheu District, Malawi.

DESIGN

A cross-sectional study was conducted in four primary schools in Ntcheu District. Data on knowledge and perception of TB were collected using a structured questionnaire. Pearson chi-square test was used to determine the association between socioeconomic factors and TB knowledge and perception. A P<0.05 was considered significant.

RESULTS

The study found that the learners had high knowledge regarding the cause, spread, and TB preventive measures. Almost 90% of learners knew that TB is caused by a germ, however, a lower proportion knew about TB symptoms ie, night sweats (49%) and enlarged cervical lymph nodes (40%). We found that 68% of learners did not know the duration of anti-TB treatment. No association was found between age, learners' grade, and knowledge (P>0.05).

CONCLUSION

Lack of knowledge regarding TB and gaps identified, may be due to a deficiency in the content of the school curriculum or the availability of information, education, and communication materials. This is the first study to report on knowledge and perceptions of TB among primary school learners in Malawi. These results will inform the development of relevant information, education, and communication materials to enhance awareness about TB among school going children.

Risk factors for tuberculosis in older children and adolescents: a matched case-control study in Recife, Brazil

Background

Tuberculosis is a major disease worldwide and most research focus on risk factors for adults, although there is a marked adolescent peak in incidence. The objective of this study was to identify risk factors for tuberculosis in children aged 7 to 19.

Methods

A case control study matched by age with 169 cases and 477 controls. The study population consisted of adolescents and older children from Recife, Brazil. Cases were individuals diagnosed with tuberculosis in the control programme and controls were selected in the neighborhood of cases. Conditional logistic regression was used to identify risk factors.

Results

Cigarette smoking increased by 50% the risk of tuberculosis but that this was not statistically significant (OR = 1.6). Other risk factors were sleeping in the same house as a case of tuberculosis (OR = 31.6), living in a house with no piped water (OR = 7.7) (probably as a proxy for bad living conditions), illiteracy (OR = 3.7) and male sex (OR = 1.8). The increase in risk with living in houses with no piped water was much more marked in males. The proportion of cases of tuberculosis attributed to contact with someone with TB was 38% and to illiteracy, lack of piped water and smoking, 20%.

Conclusion

Household contact with tuberculosis, social factors and male sex play the biggest role in determining risk of TB disease among children and adolescents in the study. We recommend further research on the relationship of cigarette smoking on tuberculosis in adolescents, and on whether the sex differentials are more marked in bad living conditions. Separate studies should be conducted in older children and in adolescents.

Yield of contact tracing from pediatric tuberculosis index cases in Gaborone, Botswana

SETTING

Contact tracing using pediatric index cases has not been adequately investigated in high tuberculosis (TB) and human immunodeficiency virus (HIV) prevalence settings.

OBJECTIVE

To determine the yield of contact tracing in household contacts of pediatric TB index cases in Botswana.

DESIGN

Index cases included all pediatric (age ≤ 13 years) TB admissions from January 2009 to December 2011 to Botswana's largest referral hospital. A contact tracing team identified cases, conducted home visits, symptom-screened contacts and referred those with ≥ 1 TB symptoms. The primary outcome was newly diagnosed TB in a contact.

RESULTS

From 163 pediatric index cases, 548 contacts were screened (median 3 contacts/case, interquartile range [IQR] 2-4). Of these, 49 (9%) were referred for positive symptoms on screening and 27/49 (55%) were evaluated for active TB. Twelve new TB cases were diagnosed (12/548, 2.2%); the median age was 31 years (IQR 23-38); 11 (92%) were smear-positive. Ten (83%) had known HIV status: 7 (70%) were HIV-positive. To find one new TB case, the number needed to contact trace (index cases/new cases) was 13.6, and the number needed to screen (contacts/new cases) was 46.

CONCLUSION

This yield of contact tracing using pediatric index cases is similar to the traditional adult index case approach. Improving the proportion of symptomatic contacts evaluated may increase yield.

Management of children exposed to Mycobacterium tuberculosis: a public health evaluation in West Java, Indonesia

OBJECTIVE

To investigate qualitatively and quantitatively the performance of a programme for managing the child contacts of adult tuberculosis patients in Indonesia.

METHODS

A public health evaluation framework was used to assess gaps in a child contact management programme at a lung clinic. Targets for programme performance indicators were derived from established programme indicator targets, the scientific literature and expert opinion. Compliance with tuberculosis screening, the initiation of isoniazid preventive therapy in children younger than 5 years, the accuracy of tuberculosis diagnosis and adherence to preventive therapy were assessed in 755 child contacts in two cohorts. In addition, 22 primary caregivers and 34 clinic staff were interviewed to evaluate knowledge and acceptance of child contact management. The cost to caregivers was recorded. Gaps between observed and target indicator values were quantified.

FINDINGS

THE GAPS BETWEEN OBSERVED AND TARGET PERFORMANCE INDICATORS WERE: 82% for screening compliance; 64 to 100% for diagnostic accuracy, 50% for the initiation of preventive therapy, 54% for adherence to therapy and 50% for costs. Many staff did not have adequate knowledge of, or an appropriate attitude towards, child contact management, especially regarding isoniazid preventive therapy. Caregivers had good knowledge of screening but not of preventive therapy and had difficulty travelling to the clinic and paying costs.

CONCLUSION

The study identified widespread gaps in the performance of a child contact management system in Indonesia, all of which appear amenable to intervention. The public health evaluation framework used could be applied in other settings where child contact management is failing.

Tuberculin Skin Test, chest radiography and contact screening in children ≤5 y: relevance in Revised National Tuberculosis Control Programme (RNTCP)

OBJECTIVES

To ascertain the status of Tuberculin Skin Test (TST) in the children aged 0-5 y who are household contacts of adults having sputum smear positive pulmonary tuberculosis and also to study the relationship of TST and Chest X-Ray (CXR) and their relevance in contact screening under RNTCP setup.

METHODS

This prospective hospital based clinical study was conducted at a tertiary level referral medical college in Northern India. Study subjects were 200 children ≤5 y of age who were household contacts of adults with sputum smear positive pulmonary tuberculosis. All these adult index cases were registered and taking regular treatment at RNTCP centre attached to a medical college. Demographic data collection, detailed clinical history along with clinical examination, growth assessment, TST and chest radiography (CXR) was done for every child.

RESULTS

TST was positive in 39 % children and out of these 68 % of child contacts had CXR findings suggestive of tuberculosis. This correlation was found to be highly significant (p < 0.001), especially in children less than 1 y of age. A high percentage of clinically asymptomatic children also had positive TST and CXR consistent with definition of TB disease.

CONCLUSIONS

Contact screening must be prioritized in RNTCP. Unlike presently, TST and CXR should be actively employed in RNTCP for contact screening.

The hidden harm of home-based care: pulmonary tuberculosis symptoms among children providing home medical care to HIV/AIDS-affected adults in South Africa

Millions of children in sub-Saharan Africa undertake personal and medical care for family members who are unwell with AIDS. To date, no research has investigated whether such care provision places children at heightened risk for pulmonary tuberculosis. This study aimed to address this gap by identifying risk factors for paediatric pulmonary tuberculosis symptomatology. In 2009-2011, 6002 children aged 10-17 years were surveyed using door-to-door household sampling of census enumeration areas. These were randomly sampled from six urban and rural sites with over 30% HIV prevalence, within South Africa's three highest tuberculosis-burden provinces. Validated scales and clinical tuberculosis symptom checklists were modelled in multivariate logistic regressions, controlling for socio-demographic co-factors. Findings showed that, among children, severe pulmonary tuberculosis symptomatology was predicted by primary caregiver HIV/AIDS-illness [odds ratio (OR): 1.63, confidence interval (CI): 1.23-2.15, p<0.001], and AIDS-orphanhood (OR: 1.44, CI: 1.04-2.00, p<0.029). Three-fold increases in severe tuberculosis symptoms were predicted by the child's exposure to body fluids through providing personal or medical care to an ill adult (OR: 3.12, CI: 1.96-4.95, p<0.001). Symptoms were also predicted by socio-economic factors of food insecurity (OR: 1.52, CI: 1.15-2.02, p<0.003) and household overcrowding (OR: 1.35, CI: 1.06-1.72, p<0.017). Percentage probability of severe tuberculosis symptoms rose from 1.4% amongst least-exposed children, to 18.1% amongst those exposed to all above-stated risk factors, independent of biological relationship of primary caregiver-child and other socio-demographics. Amongst symptomatic children, 75% had never been tested for tuberculosis. These findings identify the risk of tuberculosis among children providing home medical care to their unwell caregivers, and suggest that there are gaps in the health system to screen and detect these cases of paediatric tuberculosis. There is a need for effective interventions to reduce childhood risk, as well as further support for community-based contact-tracing, tuberculosis screening and anti-tuberculosis treatment for children caring for ill adults in contexts with a high burden of HIV and tuberculosis.

Incidence and prevalence of tuberculosis among household contacts of pulmonary tuberculosis patients in a peri-urban population of South Delhi, India

BACKGROUND

Tuberculosis (TB), caused by Mycobacterium tuberculosis, is one of the leading causes of mortality and morbidity across all age groups throughout the world, especially in developing countries.

METHODOLOGY/PRINCIPAL FINDINGS

In this study, we have included 432 open index cases with their 1608 household contacts in a prospective cohort study conducted from May 2007 to March 2009. The follow-up period was 2 years. All Index cases were diagnosed on the basis of suggestive signs and symptoms and sputum being AFB positive. Among the 432 index patients, 250 (57.9%) were males and 182 (42.1%) females; with mean age of 34 ± 14.4 yr and 26 ± 11.1 yr, respectively. Out of 1608 household contacts, 866 (53.9%) were males and 742 (46.1%) females; with mean age of 26.5 ± 15.8 and 26.5 ± 16.0 yr, respectively. Of the total 432 households, 304 (70.4%) had ≤ 4 members and 128 (29.6%) had ≥ 5 members. The median size of the family was four. Of the 1608 contacts, 1206 were able to provide sputum samples, of whom 83 (6.9%) were found MTB culture positive. Household contacts belonging to adult age group were predominantly (74, 89.2%) infected as compared to the children (9, 10.8%). On screening the contact relationship status with index patients, 52 (62.7%) were first-degree relatives, 18 (34.6%) second-degree relatives and 12 (14.5%) spouses who got infected from their respective index patients. Co-prevalent and incident tuberculosis was found in 52 (4.3%) and 31 (2.6%) contacts, respectively. In incident cases, the diagnosis could be made between 4 to 24 months of follow-up, after their baseline evaluation.

CONCLUSION

Active household contact investigation is a powerful tool to detect and treat tuberculosis at early stages and the only method to control TB in high-TB-burden countries.

Contact investigation for tuberculosis: a systematic review and meta-analysis

Investigation of contacts of patients with tuberculosis (TB) is a priority for TB control in high-income countries, and is increasingly being considered in resource-limited settings. This review was commissioned for a World Health Organization Expert Panel to develop global contact investigation guidelines. We performed a systematic review and meta-analysis of all studies reporting the prevalence of TB and latent TB infection, and the annual incidence of TB among contacts of patients with TB. After screening 9,555 titles, we included 203 published studies. In 95 studies from low- and middle-income settings, the prevalence of active TB in all contacts was 3.1% (95% CI 2.2-4.4%, I(2)=99.4%), microbiologically proven TB was 1.2% (95% CI 0.9-1.8%, I(2)=95.9%), and latent TB infection was 51.5% (95% CI 47.1-55.8%, I(2)=98.9%). The prevalence of TB among household contacts was 3.1% (95% CI 2.1-4.5%, I(2)=98.8%) and among contacts of patients with multidrug-resistant or extensively drug-resistant TB was 3.4% (95% CI 0.8-12.6%, I(2)=95.7%). Incidence was greatest in the first year after exposure. In 108 studies from high-income settings, the prevalence of TB among contacts was 1.4% (95% CI 1.1-1.8%, I(2)=98.7%), and the prevalence of latent infection was 28.1% (95% CI 24.2-32.4%, I(2)=99.5%). There was substantial heterogeneity among published studies. Contacts of TB patients are a high-risk group for developing TB, particularly within the first year. Children <5 yrs of age and people living with HIV are particularly at risk. Policy recommendations must consider evidence of the cost-effectiveness of various contact tracing strategies, and also incorporate complementary strategies to enhance case finding.

Preventive therapy in children exposed to Mycobacterium tuberculosis: problems and solutions

Young children living with a tuberculosis patient are at high risk of Mycobacterium tuberculosis infection and disease. WHO guidelines promote active screening and isoniazid (INH) preventive therapy (PT) for such children under 5 years, yet this well-established intervention is seldom used in endemic countries. We review the literature regarding barriers to implementation of PT and find that they are multifactorial, including difficulties in screening, poor adherence, fear of increasing INH resistance and poor acceptability among primary caregivers and healthcare workers. These barriers are largely resolvable, and proposed solutions such as the adoption of symptom-based screening and shorter drug regimens are discussed. Integrated multicomponent and site-specific solutions need to be developed and evaluated within a public health framework to overcome the policy-practice gap and provide functional PT programmes for children in endemic settings.

Childhood tuberculosis in household contacts of newly diagnosed TB patients

INTRODUCTION

Childhood tuberculosis (TB), although estimated to account for a major proportion of the global TB disease burden, has a lower public health priority. Reliable research and surveillance data on childhood TB is limited in most regions of the world. This study was conducted to assess the burden of childhood TB among the household contacts of new TB patients in Karachi, Pakistan.

METHODS

A retrospective analysis of children (<15 years) who were household contacts of new adult TB patients presenting to Marie Adelaide Leprosy Center (MALC) clinics in Karachi during the period of 2008 to 2010 was conducted.

RESULTS

Of the household children contacts (n = 6613) screened, 317 were suspected and 121(1.8%) diagnosed with TB. These included 89 (73.6%) with pulmonary and 32 (26.4%) with extra-pulmonary disease. Smear positivity rate in pulmonary cases was 32.6%. Mean age of children diagnosed with TB was 11.7 (± 2.8) years. Within the child-contacts screened, disease was found to be significantly higher among females (2.3%) in comparison to males (1.2%) (p-value <0.01). The commonest relationship of source cases to diagnosed children was the mother (n = 51, 42.1%). The source case was a female for 66.1% (n = 76) of the children.

CONCLUSION

A smear positivity rate of 32.6% amongst pulmonary cases suggests their potential to spread disease and emphasizes a need to review the contribution of children in transmission of TB within communities. Greater vulnerability of the female child and considerable role of mother in disease transmission highlights a need to increase focus on females in TB control programs in Pakistan.

Opportunities for chemoprophylaxis in children with culture-confirmed tuberculosis

BACKGROUND AND OBJECTIVES

Chemoprophylaxis is an effective strategy to prevent progression of tuberculosis (TB) in vulnerable children who have had contact with an infectious source of TB. However, many operational gaps prevent implementation of routine chemoprophylaxis in high-burden settings. The TB exposure status and disease spectrum in children diagnosed with culture-confirmed TB are described and missed opportunities for chemoprophylaxis are highlighted.

METHODS

All children <13 years of age diagnosed with culture-confirmed TB at a tertiary referral hospital between March 2003 and February 2007 were included. Clinical data were collected from retrospective review of files. TB was classified as pulmonary and extra-pulmonary; disseminated TB included miliary disease and TB meningitis.

RESULTS

During the study period, 614 children (327, 53·3% boys, median age 32 months) were diagnosed with culture-confirmed TB. Contact with an infectious adult source case was documented in 333 (54·2%), 237 (71·2%) of whom were <5 years of age, and 24 (7·2%) were HIV-infected and ≥5 years of age. Of those eligible for chemoprophylaxis, missed opportunities were identified in 156/221 (70·6%) children; 127 (81·4%) were <3 years of age, 39 (25%) had disseminated TB and 8 (5·1%) died. The TB source case was the mother or father in 74/156 (47·4%) children.

CONCLUSION

Opportunities for initiation of chemoprophylaxis in vulnerable children following TB exposure are often missed. Awareness should be increased among health-care workers and in the community at large regarding the importance of chemoprophylaxis in young and HIV-infected children. Health system strengthening is required to improve delivery of chemoprophylaxis to vulnerable children in close contact with newly diagnosed infectious TB cases.

Contact investigation of children exposed to tuberculosis in South East Asia: a systematic review

Background. Screening of children who are household contacts of tuberculosis (TB) cases is universally recommended but rarely implemented in TB endemic setting. This paper aims to summarise published data of the prevalence of TB infection and disease among child contacts in South East Asia. Methods. Search strategies were developed to identify all published studies from South East Asia of household contact investigation that included children (0-15 years). Results. Eleven studies were eligible for review. There was heterogeneity across the studies. TB infection was common among child contacts under 15 years of age (24.4-69.2%) and was higher than the prevalence of TB disease, which varied from 3.3% to 5.5%. Conclusion. TB infection is common among children that are household contacts of TB cases in South East Asia. Novel approaches to child contact screening and management that improve implementation in South East Asia need to be further evaluated.

Tuberculosis contact screening and isoniazid preventive therapy in a South Indian district: operational issues for programmatic consideration

Background

Under India's Revised National Tuberculosis Control Programme (RNTCP), all household contacts of sputum smear positive Pulmonary Tuberculosis (PTB) patients are screened for TB. In the absence of active TB disease, household contacts aged <6 years are eligible for Isoniazid Preventive Therapy (IPT) (5 milligrams/kilogram body weight/day) for 6 months.

Objectives

To estimate the number of household contacts aged <6 years, of sputum smear positive PTB patients registered for treatment under RNTCP from April to June'2008 in Krishna District, to assess the extent to which they are screened for TB disease and in its absence initiated on IPT.

Methods

A cross sectional study was conducted. Households of all smear positive PTB cases (n = 848) registered for treatment from April to June'2008 were included. Data on the number of household contacts aged <6 years, the extent to which they were screened for TB disease, and the status of initiation of IPT, was collected.

Results

Households of 825 (97%) patients were visited, and 172 household contacts aged <6 years were identified. Of them, 116 (67%) were evaluated for TB disease; none were found to be TB diseased and 97 (84%) contacts were initiated on IPT and 19 (16%) contacts were not initiated on IPT due to shortage of INH tablets in peripheral health centers. The reasons for non-evaluation of the remaining eligible children (n = 56, 33%) include no home visit by the health staff in 25 contacts, home visit done but not evaluated in 31 contacts. House-hold contacts in rural areas were less likely to be evaluated and initiated on IPT [risk ratio 6.65 (95% CI; 3.06–14.42)].

Conclusion

Contact screening and IPT implementation under routine programmatic conditions is sub-optimal. There is an urgent need to sensitize all concerned programme staff on its importance and establishment of mechanisms for rigorous monitoring.

Married to M. tuberculosis: risk of infection and disease in spouses of smear-positive tuberculosis patients

OBJECTIVES

To quantify the risk of infection and disease in spouses of tuberculosis patients and the extent to which intervention could reduce the risk in this highly exposed group.

METHODS

We compared HIV prevalence, TB prevalence and incidence and tuberculin skin test (TST) results in spouses of TB patients and community controls. HIV-positive spouses were offered isoniazid preventive therapy (IPT), and TST was repeated at 6, 12 and 24 months.

RESULTS

We recruited 148 spouses of smear-positive patients ascertained prospectively and 3% had active TB. We identified 203 spouses of previously diagnosed smear-positive patients, 11 had already had TB, and the rate of TB was 2.4 per 100 person years(py) over 2 years (95% CI 1.15-5.09). 116 were found alive and recruited. HIV prevalence was 37% and 39% in the prospective and retrospective spouse groups and 17% in controls. TST was ≥10 mm in 80% of HIV negative and in 57% of HIV-positive spouses ascertained retrospectively; 74% HIV negative and 62% HIV-positive spouses ascertained prospectively, and 48% HIV negative and 26% HIV-positive community controls. Of 54 HIV-positive spouses, 18 completed 6-month IPT. At 2 year follow-up, 87% of surviving spouses had TST ≥10 mm and the rate of TB was 1.1 per 100 py (95% CI 0.34-3.29).

CONCLUSIONS

Spouses are a high-risk group who should be screened for HIV and active TB. TST prevalence was already high by the time the spouses were approached but further infections were seen to occur. Uptake and adherence to IPT was disappointing, lessening the impact of short-duration therapy.

Symptom-based screening of child tuberculosis contacts: improved feasibility in resource-limited settings

OBJECTIVE

National tuberculosis programs in tuberculosis-endemic countries rarely implement active tracing and screening of child tuberculosis contacts, mainly because of resource constraints. We aimed to evaluate the safety and feasibility of applying a simple symptom-based approach to screen child tuberculosis contacts for active disease.

METHODS

We conducted a prospective observational study from January through December 2004 at 3 clinics in Cape Town, South Africa. All of the children <5 years old in household contact with an adult tuberculosis source case were assessed by documenting current symptoms and tuberculin skin test and chest radiograph results.

RESULTS

During the study period, 357 adult tuberculosis cases were identified; 195 cases (54.6%) had sputum smear and/or culture positive results and were in household contact with children aged <5 years. Complete information was available for 252 of 278 children; 176 (69.8%) were asymptomatic at the time of screening. Tuberculosis treatment was administered to 33 (13.1%) of 252; 27 were categorized as radiologically "certain tuberculosis," the majority (n = 22) of which had uncomplicated hilar adenopathy. The negative predictive value of symptom-based screening varied according to the case definition used, with 95.5% including all of the children treated for tuberculosis and 97.1% including only those with radiologically "certain tuberculosis."

CONCLUSIONS

Our findings support current World Health Organization recommendations, demonstrating that symptom-based screening of child tuberculosis contacts should improve feasibility in resource-limited settings and seems to be safe.