4. TB prevention
Preventing tuberculosis (TB) infection and stopping progression from infection to disease are critical to reduce TB incidence to the levels envisaged by the End TB Strategy. The main health care interventions to achieve this reduction are TB preventive treatment, which the World Health Organization (WHO) recommends for people living with HIV, household contacts of people with TB and other risk groups (1); TB infection prevention and control (2); and vaccination of children with the bacille Calmette-Guérin (BCG) vaccine. Addressing broader determinants that influence TB epidemics can also help to prevent TB infection and disease; these are discussed in Section 6.3.
TB preventive treatment: overall status of progress
The global number of people living with HIV and household contacts of people diagnosed with TB who were provided with TB preventive treatment increased from 1.0 million in 2015 to 3.6 million in 2019, after which there was a sizeable reduction in 2020 (to 3.2 million) followed by an almost complete recovery in 2021 (to 3.5 million), probably reflecting disruptions to health services caused by the COVID-19 pandemic (Fig. 4.1). Most of those being provided with TB preventive treatment are people living with HIV. The number of children under 5 provided with TB preventive treatment has not increased substantially over the last three years; in contrast, 260 000 household contacts aged 5 years and over were started on TB preventive treatment in 2021, a 90% increase compared to the 137 000 that started treatment in 2020.
Fig. 4.1 The global number of people provided with TB preventive treatment, 2015–2021
Progress made in the past 4 years lags far behind that needed to reach the global target set at the UN high-level meeting on TB (Fig. 4.2). Although the sub-target
for people living with HIV had been achieved by 2020, further scale-up will be needed to reach the target of providing TB preventive treatment to 90% of people living with HIV by 2025 (3),
which was reaffirmed at the 2021 UN high-level Meeting on HIV and AIDS (4).
Fig. 4.2 Global progress in provision of TB preventive treatment 2018–2021 compared with cumulative targets set for 2018–2022 at the UN high-level meeting on TB
Ensuring access to shorter rifapentine-containing regimens may help to increase access to TB preventive treatment. By June 2022, 78 countries reported that they had used shorter rifapentine-containing regimens (including trials and subnational
projects) (Fig. 4.3). In 2021, over 185 000 individuals started shorter regimens in 52 countries. Rifapentine-based regimens were used in 34 countries (mostly a 3-month
weekly regimen of rifapentine and isoniazid); 42 countries reported using a rifampicin-based regimen.
Fig. 4.3 Use of rifapentine in TB preventive treatment regimens,a by June 2022
a Data sources: Sanofi, Global Drug Facility and national reporting. Rifapentine is currently registered for use in China, Hong Kong Special Administrative Region, the Democratic Republic of the Congo, Ethiopia, Ghana, India, Indonesia,
Kenya, Mongolia, Myanmar, Namibia, the Philippines, Singapore, South Africa, Thailand, Turkmenistan, Uganda and the United States of America. Several countries in which rifapentine is not yet registered have accessed it using local waiver
mechanisms.
Household contacts
Globally in 2021, 7.5 million contacts of bacteriologically confirmed pulmonary TB cases were reported (up 7.2% from 7.0 million in 2020), of whom 6.3 million (84%) were evaluated for both TB infection and disease (up 63% from 3.9 million in 2020). The percentage of contacts who were evaluated varied widely among countries (Fig. 4.4). There is considerable variation in the coverage of TB preventive treatment for eligible children aged under 5 years (Fig. 4.5). Data on treatment completion among household contacts were reported by 76 countries; the median completion rate was 86% (IQR, 68–94%) but varied widely (Fig. 4.6).
Fig. 4.4 Percentage of household contacts of bacteriologically confirmed pulmonary new and relapse TB cases evaluated for TB disease and TB infection, 2021
People living with HIV
Most of those provided with TB preventive treatment to date have been people living with HIV (Fig. 4.1). Globally, the annual number increased from fewer than 30 000 in 2005 to 3.0 million in 2019 before falling in 2020 and 2021 (to 2.7 million and 2.8 million respectively) (Fig. 4.7). Between 2005 and the end of 2021, 16 million people living with HIV were initiated on TB preventive treatment, equivalent to about 42% percent of the 38 million people estimated to be living with HIV in 2021 (5). There were reductions in most WHO regions between 2019 and 2020, with recovery only in the African and Eastern Mediterranean regions in 2021 (Fig. 4.7).
Fig. 4.7 Provision of TB preventive treatment to people living with HIVa, 2005–2021
a For the period 2005-2016, countries were requested to report data for people newly enrolled in HIV care (dashed lines). Susequently, countries have been encouraged to report data for people currently on antiretroviral treatment (solid
lines).
Seven countries (India, Nigeria, South Africa, Uganda, United Republic of Tanzania, Zambia and Zimbabwe) each reported initiating over 200 000 people with HIV on TB preventive treatment in 2021, accounting collectively for 82% of the
2.8 million reported globally (Fig. 4.8).
Coverage of TB preventive treatment among people living with HIV varies widely among countries: in 13 high TB/HIV burden countries that reported data for 2021, the median coverage was 58% (interquartile range [IQR], 32–65%) among people newly started on antiretroviral treatment.
In 20 countries reporting data, a median of 87% (IQR, 64–96%) of people living with HIV who started TB preventive treatment in 2020 completed it (Fig. 4.9).
Tests for TB infection
Tests for TB infection can help to target TB preventive treatment to people who can benefit the most from it. In 2021, 115 countries reported using tuberculin skin tests (TST) or interferon gamma release assays (IGRA) in either the public or private sectors to deliver TB preventive treatment to populations at risk (Fig. 4.10). Of the 36 countries reporting no use of tests of TB infection, 29 were in the WHO African Region.
TB infection prevention and control
The risk of TB among health care workers relative to the risk in the general adult population is one of the indicators recommended by WHO for measuring the impact of interventions for TB infection prevention and control in health care facilities. If effective prevention measures are in place, the risk ratio for TB in health care workers compared with the general adult population should be close to 1. In 2021, 16 931 health care workers from 69 countries were reported to have been diagnosed with TB. The ratio of the TB notification rate among health care workers to the general adult population was greater than 1 in 14 countries that reported five or more TB cases among health care workers (Fig. 4.11).
BCG vaccination
BCG vaccination is recommended as part of national childhood immunization programmes, in line with a country’s TB epidemiology. Global coverage dropped from 88% in 2019 to 84% in 2021, most likely due to disruptions to health services caused by the COVID-19 pandemic (Fig. 4.12).
Fig. 4.12 BCG vaccination coverage in infantsa, globally and by WHO region 2015–2021
a Data for 2021 were reported by 156 out of 194 WHO Member States (47/47 in the African Region, 27/35 in the Region of the Americas, 11/11 in the South-East Asia Region, 28/53 in the European Region, 19/21 in the Eastern Mediterranean
Region and 24/27 in the Western Pacific Region).
Source: The
Global Health Observatory, accessed 10 August 2022.
Country-specific details are available in the Global tuberculosis report app and country profiles.
Data shown on this webpage are as of 29 August 2022 (see Annex 2 of the main report for more details).
References
WHO consolidated guidelines on tuberculosis. Module 1: Prevention – Tuberculosis preventive treatment. Geneva: World Health Organization; 2020 (https://www.who.int/publications/i/item/9789240001503).
WHO guidelines on tuberculosis infection prevention and control. 2019 update. Geneva: World Health Organization; 2019. (https://www.who.int/publications/i/item/9789241550512)
Implementing the End TB Strategy: the essentials. Geneva: World Health Organization, 2015. (https://www.who.int/publications/i/item/9789241509930).
United Nations General Assembly. 75th session. Item 10 of the agenda. Implementation of the Declaration of Commitment on HIV/AIDS and the political declarations on HIV/AIDS. Draft resolution submitted by the President of the General Assembly. Political Declaration on HIV and AIDS: Ending Inequalities and Getting on Track to End AIDS by 2030 (A/75/L.95). New York: United Nations; 2018 (https://www.un.org/pga/75/wp-content/uploads/sites/100/2021/06/2107241E1.pdf).
UNAIDS epidemiological estimates, 2022 (https://aidsinfo.unaids.org/).