Research: Regional changes in TB disease burden among adolescents in South Africa

09 Jul 2020
Regional changes in tuberculosis disease burden among adolescents in South Africa (
09 Jul 2020

SATVI researchers Eric Wekasa Bunyasi, Mark Hatherill, Humphrey Mulenga, Angelique Luabeya, Justin Shenje, Simon Mendelsohn, Elisa Nemes and Tom Scriba have published a research paper titled "Regional changes in tuberculosis disease burden among adolescents in South Africa (2005–2015)" appearing in the PLOS ONE journal.  

Background: Adolescents in the Western Cape Province of South Africa had high force of Mycobacterium tuberculosis (MTB) infection (14% per annum) and high TB incidence (710 per 100,000 person–years) in 2005.

We describe subsequent temporal changes in adolescent TB disease notification rates for the decade 2005–2015.

Comparison of adult and adolescent TB trends 2005–2015
Comparison of adult and adolescent TB trends 2005–2015. Legend: TB = Tuberculosis disease (all TB). A = The period of rollout of Xpert MTB/RIF assay as a replacement for sputum smear microscopy. Between 2005–2015 all–TB rates declined by 15% from 2,750 to 2,331 per 100,000 among children; by 45% from 662 to 361 per 100,000 among adolescents; and by 30% from 1,423 to 994 per 100,000 among adults. P–value is for temporal trend between 2005–2015.

This study conducted an analysis of patient–level adolescent (age 10–19 years) TB disease data, obtained from an electronic TB register in the Breede Valley sub–district, Western Cape Province, South Africa, for 2005–2015. Numerators were annual TB notifications (HIV–related and HIV–unrelated); denominators were mid–year population estimates. Period averages of TB rates were obtained using time series modeling. Temporal trends in TB rates were explored using the Mann–Kendall test.

 The study found that the average adolescent TB disease notification rate was 477 per 100,000 for all TB patients (all–TB) and 361 per 100,000 for microbiologically–confirmed patients. The adolescent all–TB rate declined by 45% from 662 to 361 per 100,000 and the microbiologically–confirmed TB rate by 38% from 492 to 305 per 100,000 between 2005–2015, driven mainly by rapid decreases for the period 2005–2009. There was a statistically significant negative temporal trend in both all–TB (per 100,000) (declined by 48%; from 662 to 343; p = 0·028) and microbiologically confirmed TB (per 100,000) (declined by 49%; from 492 to 252; p = 0·027) for 2005–2009, which was not observed for the period 2009–2015 (rose 5%; from 343 to 361; p = 0·764 and rose 21%; from 252 to 305; p = 1·000, respectively).

Regional changes in tuberculosis disease burden among adolescents in South Africa (2005-2015)
Figure: Adolescent TB temporal trends by age and year. Legend: TB = Tuberculosis disease (all–TB). Panel 3A. Adolescent TB disease rates by age and year. Between 2005–2015, TB rates declined by 63% (from 429 to 157 per 100,000; p–value for temporal trend (p–value) = 0�350) among adolescents aged 10 years old; by 29% (from 560 to 400 per 100,000; p–value = 0�640 among adolescents aged 15 years old; and by 40% (from 1120 to 677 per 100,000; p– value = 0�020) among adolescents aged 19 years old. Panel 3B. Adolescent TB disease rates by five–year age groups. TB rates declined by 60% (from 379 to 151 per 100,000) among adolescents aged 10–14 years old; and by 40% (from 938 to 566 per 100,000) among adolescents aged 15–19 years old. P–value is for temporal trend between 2005–2015.

We observed an encouraging fall in adolescent TB disease rates between 2005–2009 with a subsequent plateau during 2010–2015, suggesting that additional interventions are needed to sustain initial advances in TB control.

Citation: Bunyasi EW, Mulenga H, Luabeya AKK, Shenje J, Mendelsohn SC, Nemes E, Tameris M, Wood R, Scriba TJ, Hatherill M. 2020. Regional changes in tuberculosis disease burden among adolescents in South Africa (2005-2015). PLoS One, 15(7):e0235206. Click here.