title: Household Contact Screening and Yield of Tuberculosis Cases-A Clinic Based Study in Chennai, South India.
abstract: BACKGROUND
  Contact investigation is an active case finding strategy to increase detection of Tuberculosis (TB) and a key component of TB control programs. The household contacts are at a higher risk of exposure than members of the general population. The information on the value and yield of household contact screening and the approaches used in high incidence settings like India is limited.
  
  
  OBJECTIVE
  To evaluate the yield of active case finding in household contacts of newly diagnosed smear positive TB patients and the factors associated with increased yield.
  
  
  METHODS
  Retrospective record review of the household contacts of newly diagnosed sputum smear positive patients (index case) enrolled in a clinical trial at National Institute of Research in Tuberculosis, Chennai during the period 2007-2014. A sequential screening algorithm with chest x-ray followed by symptom screen was employed to identify presumptive TB patients.
  
  
  RESULTS
  643 household contacts of 280 index TB patients were identified out of which 544 (85%) consented for screening. 71/544 (13%) patients had an abnormal chest radiograph and out of them 70% were symptomatic. A total of 29/544 (5.3%) contacts were found to have TB among whom 23/29 (79%) were sputum smear positive. The number needed to screen (NNS) to identify a new TB case among all household contacts was 19 and among those with an abnormal CXR was 02. Age group > 44 years, male gender and siblings of the index case was associated with abnormal chest radiograph whereas age group between 15-44 was significantly associated with developing TB disease among household contacts.
  
  
  CONCLUSIONS
  Active screening among household contacts is an effective way to improve TB case detection. The yield for new TB cases among contacts with abnormal x-ray was high in this study and the use of Chest X-rays in combination with symptom screen is recommended.
authors: National Institute for Research in Tuberculosis, Chennai, India.
authors: Dina
authors: D
authors: Nair
authors: Mailman School of Public Health, Columbia University, New York City, United States of America.
authors: Nandita
authors: N
authors: Rajshekhar
authors: National Institute for Research in Tuberculosis, Chennai, India.
authors: Joel Shyam
authors: JS
authors: Klinton
authors: National Institute for Research in Tuberculosis, Chennai, India.
authors: Basilea
authors: B
authors: Watson
authors: National Institute for Research in Tuberculosis, Chennai, India.
authors: Banurekha
authors: B
authors: Velayutham
authors: International Union against Tuberculosis and Lung Disease, The Union South-East Asia Office, New Delhi, India.
authors: Jaya Prasad
authors: JP
authors: Tripathy
authors: National Institute for Research in Tuberculosis, Chennai, India.
authors: Mohideen Shaheed
authors: MS
authors: Jawahar
authors: Indian Council of Medical Research, New Delhi, India.
authors: Soumya
authors: S
authors: Swaminathan
mesh_terms: D000328:Adult; D016358:Contact Tracing; D005191:Family Characteristics; D005260:Female; D006801:Humans; D015994:Incidence; D007194:India / Q000453:epidemiology; D008297:Male; D014376:Tuberculosis / Q000453:epidemiology*