Related Experiment Video
Updated: Jul 15, 2025
A Suction Blister Protocol to Study Human T-cell Recall Responses In Vivo
Published on: August 11, 2018
Contact Investigations With a Single Tuberculin Skin Test on Infants Exposed to Tuberculosis in a Postpartum Care
Soo-Han Choi1,2, Chi Eun Oh3, Jungmin Lee4
1Department of Pediatrics, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Korea.
Insights
A single tuberculin skin test (TST) after isoniazid (INH) prophylaxis is effective for investigating tuberculosis (TB) exposure in neonates. This approach helps manage latent TB infection (LTBI) in infants without progression to active disease.
Area of Science:
- Pediatrics
- Infectious Diseases
- Public Health
Background:
- Neonatal tuberculosis (TB) exposure in congregate settings presents significant medical and social challenges.
- Current contact investigations for infants are often delayed and face diagnostic hurdles due to differing screening recommendations for neonates versus children.
Purpose of the Study:
- To evaluate the efficacy of a single tuberculin skin test (TST) combined with isoniazid (INH) prophylaxis for contact investigations in neonates exposed to infectious TB.
Main Methods:
- The study involved 288 infants exposed to an index case of active pulmonary TB.
- Infants received medical examinations, chest X-rays, and window period prophylaxis with INH.
- A single TST was administered three months after the last TB exposure, after prophylaxis completion.
Main Results:
- The prevalence of latent TB infection (LTBI) among exposed infants was 25.3%.
- No infants developed active TB disease during the one-year follow-up.
- Factors associated with positive TST included male sex, percutaneous BCG vaccination, delayed TST reading, and INH prophylaxis duration.
Conclusions:
- A single TST performed three months post-exposure, following INH prophylaxis, is a viable primary strategy for TB contact investigations in neonates in congregate settings.
- This protocol effectively identifies LTBI and prevents progression to active TB disease in infants.
Background:
Tuberculosis (TB) exposure in congregate settings related to neonates is a serious medical and social issue. TB exposure happens during the neonatal period, but contact investigations for exposed infants are usually conducted after the neonatal period. Generally, recommendations for screening and managing close contact are different for neonates and children. Thus, there are challenges in contact investigations. We aimed to report contact investigations with a single tuberculin skin test (TST) on infants exposed to infectious TB in a postpartum care center.
Methods:
The index case was a healthcare worker with active pulmonary TB: sputum acid-fast bacilli smear negative, culture positive, and no cavitary lesion. All exposed infants underwent medical examinations and chest X-ray. After TB disease was ruled out, contacts received window period prophylaxis with isoniazid (INH) until three months after the last exposure. TST was performed only once after completing the prophylaxis.
Results:
A total of 288 infants were selected as high-priority contacts. At the initial contact investigation, the age of infants ranged from 8 to 114 days. None of these exposed infants had TB disease. The prevalence of latent TB infection (LTBI) was 25.3% (73/288; 95% confidence interval [CI], 20.7-30.7). There were no serious adverse events related to the window period prophylaxis or LTBI treatment with INH. During the 1-year follow-up period, no infants progressed to overt TB disease. The size of TST induration in infants vaccinated with percutaneous Bacillus Calmette-Guérin (BCG) vaccine was significantly larger than that of infants vaccinated with intradermal BCG vaccine (median, 8 mm vs. 5 mm; P = 0.002). In multiple logistic regression analysis, independent factors associated with TST positivity (≥ 10 mm induration) were male (adjusted odds ratio [aOR], 2.98; 95% CI, 1.6-5.64), percutaneous BCG vaccination (aOR, 3.30; 95% CI, 1.75-6.48), TST reading between 60 and 72 hours after injecting purified protein derivative (aOR, 2.87; 95% CI, 1.53-5.49), and INH prophylaxis more than four weeks (aOR, 0.49; 95% CI, 0.25-0.94).
Conclusion:
A single TST at three months after the last TB exposure with INH prophylaxis could be used as a main protocol in contact investigations for infants exposed to infectious TB during the neonatal period in congregate settings in Korea.
More Related Videos
06:26Author Spotlight: Optimizing CFU Determination for Efficient Assessment of TB Vaccine Efficacy and Antigen Presentation Analysis
Published on: July 28, 2023
10:04Analysis of 18FDG PET/CT Imaging as a Tool for Studying Mycobacterium tuberculosis Infection and Treatment in Non-human Primates
Published on: September 5, 2017
Related Concept Videos
01:26Pulmonary Tuberculosis IV
Several diagnostic approaches are used to detect TB. The conventional method is the Tuberculin Skin Test (TST), also known as the Mantoux test. However, this method has...
01:31Pulmonary Tuberculosis III
The first classification is based on the development of the disease, and it includes the following categories:
01:28Pulmonary Tuberculosis V
Latent tuberculosis infection occurs when TB bacteria are present in a person's body, but are not causing illness or symptoms. It is not contagious, and preventive treatment is crucial to avoid the...
01:29Pulmonary Tuberculosis I
Causative Organism
The primary infectious agent causing tuberculosis is Mycobacterium tuberculosis, a slow-growing, acid-fast, aerobic rod that exhibits sensitivity to heat and ultraviolet light. Instances of Mycobacterium bovis and Mycobacterium avium contributing to the development of TB infection are rare.
Mode of...
01:28Pulmonary Tuberculosis II
Here is a detailed explanation of its pathophysiology:
Transmission: The process begins when a person inhales droplet nuclei containing M. tuberculosis. These are typically released into the air when an individual with pulmonary or...
01:22Development of Immunocompetence
The initial cells that migrate from the fetal thymus settle within the skin and epithelial tissues lining the mouth, digestive tract, and in females, the uterus and vagina. These cells, including skin-based dendritic cells, serve as antigen-presenting cells, playing a key role in T cell activation.
Subsequent T...