latent tuberculosis in children less than 12 years of age in tertiary care center

2. Latent Tuberculosis Infection
(LTBI) in Children Less than
12 Years of Age in a Tertiary
Care Centre, Lahore, Pakistan

3. Authors
Afzal MF, Iqbal SMJ, Masood A, Sultan MA, Hanif
Source
Pak Pediatr J 2017; 41(4): 207-10

4. Place of Study
Department of Pediatrics,
King Edward Medical University, Lahore.
Study design
Cross-sectional study

6. LTBI is a condition in which M.tuberculosis
survives in the body in a dormant state. Persons
with latent TB:
 Don’t show any symptoms of disease
 Are not infectious
 Transition to Active TB is frequent and
faster(weeks)
 Conversion rate is 5% in 2 years

7.  Tuberculosis (TB) is leading causes of
morbidity and mortality in all age groups
 World Health Organization (WHO) has
estimated that 13.7 million population in the
world has active TB
 about 1 million (11%) of them are children
<15 years of age
 This figure varies from 3% to 25% in different
countries.
 1/3 of world population is having LTBI

8.  Sputum smear-positive and culture-
confirmed patients with TB pose high risk for
developing LTBI in the close contacts.
 . QuantiFERON®-TB Gold in-tube test (QFT-
GIT) has been introduced as new diagnostic
tests for LTBI
 compared to TST, QFT-GIT assay has a
comparable sensitivity, while superior
specificity and no false positive results

9.  Individuals with LTBI represent a reservoir of
infection, leading to progression to the
disease.
 Early detection of the LTBI cases will decline
mortality and also the overall burden of the
disease.
 Addressing LBTI reservoir is critical to achieve
elimination.

10.  Prevalence of TB in Pakistan = 44%
 Registered cases of TB in children = 4%
 Risk of getting infection in children = 2.5%
 Will progress to primary disease = 5%-10%
of infected children
 Will get latent tuberculosis infection (LTBI) =
80-90% of infected children

11. Study : Cross sectional study
Location : peads dept. KEMU
Duration :July 2014 to June 2015
Sample size : 250
Sample technique : Non-probability convenient
sampling, 250 children (using 20% prevalence of
childhood TB in Pakistan, 95% confidence interval &
5% margin of error)

12.  Presence or absence of BCG vaccination scar was
documented.
 All children were subjected to QFT-GIT for
evidence of LTBI.
 All QFT-GIT test positive subjects underwent
further clinical investigation with symptom query,
and chest x-ray for detection of active disease
 Data were analyzed by SPSS 20.0

13.  Total of 250 children 1-12 years of age were
enrolled. The mean age was 6.48 ± 2.97
years
Variables
 Gender
 BCG scar
 Age

14. Children having contact with:
 Confirmed (sputum positive adult case of
pulmonary TB)
 Suspected tuberculosis case (adult having
fever and unremitting cough for 3 weeks)
 Non-responsive to conventional treatment
based on history and available clinical record.

15.  Diagnosed cases of TB were excluded

16. Study results:
Out of 250, 75 (30%) of children were found to be
suffering from LTBI as evident by positive QFT-GIT
Demographic results:
 Among 250, 136 (54.4%) were male and 114
(45.6%) were female.
 Positive male and female were 14% and 16%
respectively
.

19.  When data were analyzed for BCG scar and
QFT-GIT positivity, it was found that 8.4%
vaccinated male and 10% vaccinated female
were affected, whereas 17.6% of children less
than 5 years were having LTBI.

21.  Tuberculosis control program in Pakistan is
generally facing low case detection rates.
 LTBI constitute hidden pools, feeding the new
cases.
 Present study had reported the 30% prevalence of
LTBI among study population, among which male
and female were 14% and 16% respectively.

22.  No local data about LTBI in children to compare
the results
 Mancuso et al from United States reported the
estimated prevalence of LTBI as 4.8%.
 Kizza et al13 from South Africa reported overall
prevalence of LTBI as 49% and authors observed
the increase in overall LTBI prevalence with age.
Authors also observed the higher prevalence of
LTBI in males as compared to females.

23.  BCG has failed to protect adults against active
pulmonary tuberculosis, especially in countries
where the disease is endemic
 Despite the prior vaccination with BCG, a
positive QFT-GIT in a child having close contact
with infectious adult most likely represents LTBI
 there should be consideration for treatment of
LTBI, especially if the child is younger than 5
years.

24. Merits:
 Appropriate study design
 Appropriate sample size
 Sampling technique defined
 Practical
 Achieving its objective
 Inclusion and exclusion criteria is well defined
 Purpose well defined

25.  Tables are understandable
 Funding source disclosed
 Results discussed acc to objective
 Research findings compared with other
studies
 Limitations of study mentioned

26. Confounding variables
 Nutritional status
 Income
 Immunosuppressed cases

27.  Single centered
 Hospital based
 Not true reflection of community
 Study population not defined
 Ethical consideration

28.  The prevalence of latent tuberculosis
infection in children less than 12 years of age
is 30%.
 It is need of time to screen each child for
LTBI who has close contact with adult case of
TB in developing countries like Pakistan

29.  Consideration of Immunosuppressed
children(HIV +) for LTBI
 Ethical consideration
 Basis of sample size could have been
mentioned
 Study could be done at multiple centers for
better reflections of LTBI prevalence

30. ANY SUGGESTIONs ???

32.  Used 3cc non-heparinized whole blood
sample.
 The sample was taken into 3 pre-coated
tubes (2 control tubes and 1 TB antigen tube)
 One of the controls had nil antigen serving
as negative control while the other had a
mitogen protein serving as positive control.
There were 3 peptides specific to MTB in TB
antigen tube: ESAT-6, CFP-10 and TB7.7.

33.  The amount of interferon gamma release
assay was measured by ELIZA after 16-24
hours incubation.
 The interpretation of test was as “positive”
(IFN-g response level was at least 0.35 IU/ml
over the nil concentration), and
“indeterminate” (Nil concentrations of at least
8.0 IU/ml and mitogen differences of less
than 0.5 IU/ml).
 In our study, we did not have indeterminate
QFT-GIT results