High Prevalence of and Risk Factors for Latent Tuberculosis Infection among Prisoners, Tianjin, China

Abstract

T uberculosis (TB) remains a global threat to human health. In 2018, a total of 10 million cases of TB and 1.5 million deaths from TB were reported by the World Health Organization (WHO) (1). Globally, TB notification rates for prisoners are 11-81 times higher than those for local general populations (2). An estimated 10.4 million persons are held in penal institutions throughout the world, and each year the number of persons passing through prison gates could be 4-6 times higher because of high turnover of inmates (3). TB in prisons might spread to the civilian population through staff, visitors, and released prisoners because of inadequate treatment for TB and thus could affect TB control in the general population (4,5). China has the second highest burden of TB in the world (0.9 million incident TB cases during 2018) (1). There were ≈1.7 million prisoners in China during 2016 (3). However, similar to the situation in other countries, TB control in prisons remained largely neglected (6,7). Tianjin, located in northern China, has ≈16 million permanent residents and is one of the pioneering regions for TB control in China. This city had systematically implemented active TB case-finding and directly observed treatment using short-course chemotherapy in all prisons according to the guidelines (8,9). However, despite major achievements, TB incidence among prisoners is still much higher than in the general population in Tianjin (10). It is essential to conduct interventions to identify latent TB infection (LTBI) through screening and prophylaxis in prisons (11). To achieve this goal, we conducted a study to evaluate the prevalence of and risk factors for LTBI by using an interferon-γ release assay (IGRA) in 8 prisons in Tianjin, China. Methods We conducted a baseline cross-sectional study in Tianjin during 2016, followed by providing prophylaxis to prisoners with LTBI and consecutive surveillance of TB incidence. We determined the necessary sample size as >880 persons by using Epi Info (https://www. cdc.gov/epiinfo) to satisfy a cross-sectional design for estimation of LTBI (>480 persons) and a community randomized control trial design (>880 persons). The 8 prisons contained 14,401 prisoners (>18 years of age) and were composed of separate wards, each containing ≈200 persons. Sampling was performed by using a 2-stage process and ward clustering; persons in selected wards participated in a screening procedure for the study.

Prevalence of latent tuberculosis infection and feasibility of TB preventive therapy among Thai prisoners: a cross-sectional study

“…Surprisingly the 61.6% prevalence of positive QFTP was much higher than the 13 and 20% prevalence in reported in Thai people living with HIV (PLWH) [ 13 ] and Thai health care workers, respectively [ 14 ] who were also tested by IGRA. Furthermore, this positive IGRA prevalence was higher than that reported from correctional facilities in other high TB burden countries such as China (52%) [ 15 ] and Ethiopia (51%) [ 16 ].…”

“…Having been incarcerated ≥10 years, or having a previous incarceration were independent risk factors associated with LTBI prevalence in our study. Many previous studies have demonstrated that previous incarceration was a risk factor for LTBI in prisons, regardless of the TB burden in the country [ 15 , 17 , 20 , 32 ]. Furthermore, a longer duration of incarceration was associated with LTBI among Chinese [ 15 ] and Ethiopian [ 16 ] prisoners.…”

“…Many previous studies have demonstrated that previous incarceration was a risk factor for LTBI in prisons, regardless of the TB burden in the country [ 15 , 17 , 20 , 32 ]. Furthermore, a longer duration of incarceration was associated with LTBI among Chinese [ 15 ] and Ethiopian [ 16 ] prisoners. This finding underscores the cumulative nature of the risk of TB transmission among prisoners, and highlights the public health importance of implementing LTBI screening and treatment in this setting.…”

Epidemiology and control strategies for tuberculosis in countries with the largest prison populations

“…The magnitude of LTBI in the prison system is poorly understood; however, some studies have reported high rates of LTBI. This is the case for prisons in China, in 2016, with an LTBI rate above 50%, which is higher than that of the general population (13.5-24.3%), using an interferon-γ release assay (IGRA) 34 . From August 2018-November 2019, Gatechompol et al (2021) conducted a study in a maximum-security prison in Thailand, with 46.5% of patients testing positive for LTBI using tuberculin skin test (TST) and IGRA 35 .…”

Latent tuberculosis infection in the Polish prison staff

“…Tendencja do zachorowania wzrasta w grupach zwiększonego ryzyka i dotyczy to szczególnie bezdomnych, imigrantów i więźniów [6]. Więzienia, które są często nazywane rezerwuarami chorych na gruźlicę, stwarzają szczególnie duże zagrożenie dla zatrudnionych w aresztach i zakładach karnych, a także pośrednio dla społeczeństwa [7]. Więźniowie należą do grup wysokiego ryzyka oraz są na ogół biedni, mają niskie wykształcenie i pochodzą z grup ludności o niskim statusie ekonomiczno-społecznym, gdzie poziom zakażenia i przenoszenia gruźlicy jest wyższy.…”