1. COVID-19 pandemic and TB

A widely available indicator that can be used to assess the impact of disruptions caused by the COVID-19 pandemic on essential TB services at country level is the national number of monthly or quarterly notifications of people diagnosed with TB. This indicator reflects impacts on access to diagnosis and treatment on both the supply side (e.g. capacity to continue to provide services) and the demand side (e.g. willingness and ability to seek care in the context of lockdowns and associated restrictions on movement, concerns about the risks of going to health care facilities during a pandemic, and stigma associated with similarities in symptoms related to TB and COVID-19). After successfully collecting such data from 14 high TB burden countries for January–June 2020 (1), in January 2021 WHO established a global system for regular collection of monthly and quarterly notification data from more than 100 countries, initially for the whole of 2020 and then for 2021, with visualizations of all reported data available in real time (2–4).

Following large increases in the global number of TB case notifications per year between 2017 and 2019, the reported data show a substantial fall of 18% between 2019 and 2020, from 7.1 million to 5.8 million (Fig. 1.1). This set back, coupled with continued disruptions in 2021, mean that the United Nations (UN) high-level meeting target of treating 40 million people diagnosed with TB in the 5-year period 2018–2022 is off-track.

A similar pattern of increases in notifications up to 2019 followed by a sharp fall in 2020 is also evident in four of the six WHO regions (Fig. 1.2), with particularly large absolute and relative reductions in the regions of South-East Asia and the Western Pacific. In combination, these two regions accounted for 84% of the global reduction in TB case notifications between 2019 and 2020. The decline in the WHO African Region was much more modest (2.5%). In the WHO European Region, there was a clear discontinuity in an existing downward trend in notifications (reflecting an underlying decline in TB incidence), suggesting that detection and reporting of TB cases in this region was also affected by the COVID-19 pandemic.

Monthly and quarterly TB notifications in 2020 and the first half of 2021 were substantially below the average for 2019 in most of the high TB burden countries (Fig. 1.3, Fig. 1.4), with the largest relative reductions in annual notifications between 2019 and 2020 seen in Gabon (80%), the Philippines (37%), Lesotho (35%), Indonesia (31%) and India (25%) (Fig. 1.5). Exceptions to this general pattern included the Democratic Republic of Congo, Nigeria, the United Republic of Tanzania and Zambia (Fig. 1.3).

Reasons for regional and country variation in TB notification trends between 2019 and 2020 include differences in when they were first affected by the COVID-19 pandemic, the severity of the impact, the extent to which restrictions were put in place and adhered to, and the capacity and resilience of health systems.

Data presented elsewhere in this report suggest that other impacts associated with the COVID-19 pandemic include a 15% decline in people enrolled on treatment for MDR/RR-TB (Section 3.4); a downturn in the number of people initiated on TB preventive treatment between 2019 and 2020 (from 3.6 million to 2.8 million; Section 4); a reduction in spending on TB prevention, diagnostic and treatment services between 2019 and 2020 (from US$ 5.8 billion to US$ 5.3 billion; Section 5); and a reduction in coverage of the bacille Calmette-Guérin (BCG) vaccine among children between 2019 and 2020 (5% or more in 31 countries; Section 4).

The monthly and quarterly notification data reported by countries for 2020 have been used to produce provisional global, regional and country-specific estimates of TB incidence and TB mortality for that year. Dynamic models were developed for 16 countries, prioritized based on the size of their contribution to the global shortfall in TB notifications in 2020 compared with 2019 (Fig. 1.6). It was assumed that reductions in notifications in 2020, relative to the expected number of monthly or quarterly notifications in 2020 based on extrapolation of pre-2020 trends, were attributable to delays in diagnosis and initiation of treatment. Results were then extrapolated to other low- and middle-income countries using a statistical model. For high-income countries, incidence was estimated using case notification data with a standard adjustment, whereas mortality was estimated using data from national vital registration systems. Further details about methods are provided in Section 2 and a technical annex.

Globally, disruptions to the provision of and access to TB diagnostic and treatment services due to the COVID-19 pandemic are estimated to have caused an increase of about 100 000 in the global number of TB deaths between 2019 and 2020 (an increase from 1.2 million to 1.3 million in HIV-negative people, with about 5000 additional TB deaths among HIV-positive people). These disruptions have also caused a slight slowing in the annual decline in the global TB incidence rate (Section 2).

Projections of TB incidence and mortality for the 16 modelled countries up to 2025 suggest that these impacts will be much larger in 2021 and beyond, especially on TB mortality in 2021 and TB incidence in 2022 (Fig. 1.7, Fig. 1.8). In 2021, TB mortality is projected to be much higher than in 2020 in all of these 16 countries and by 2022, TB incidence is projected to be above the level of 2020 in most of them, consistent with other modelling projections published in 2020 (5–8). Moreover, these impacts could be underestimates because the modelling does not yet account for the impact of the COVID-19 pandemic on broader TB determinants, such as levels of poverty and undernutrition, which increase the rate of disease breakdown among infected individuals. Declines in income may also affect health care seeking behaviour when people become unwell, causing delays in TB diagnosis and treatment. There is a strong association between the TB incidence rate and both average income (measured as gross domestic product [GDP] per capita) and the prevalence of undernutrition (Section 6).

There are two main reasons for the more delayed impact on TB incidence compared with TB mortality. The first is that disruptions to diagnostic and treatment services affect those who already have TB disease first, resulting in an increase in the number of deaths. The second is that the impact on incidence of the increased pool of prevalent cases that develops as more people with TB are not diagnosed and treated is slow, due to the relatively long period of time between the acquisition of infection and the development of disease (which ranges from weeks to decades). Other sources of information about the impact of the COVID-19 pandemic on TB include a review of data published between January 2020 and March 2021 (9), a study of changes in TB services provided in 19 countries between 2019 and 2020 (10) and a compendium of research studies related to TB and COVID-19 (11). 

WHO has issued guidance on TB in the context of the COVID-19 pandemic (12, 13). Advice includes:

• leverage the expertise and experience of NTPs, especially in rapid testing and contact tracing, for the COVID-19 response;

• maximize remote care and support for people with TB by expanding the use of digital technologies;

• minimize the number of visits to health services that are required during treatment, including through the use of WHO-recommended, all-oral TB treatment regimens and community-based care;

• limit the transmission of TB and COVID-19 in congregate settings and health care facilities by ensuring basic infection prevention and control for health staff and patients, cough etiquette, and patient triage;

• support the provision of TB preventive treatment by building synergies with contact-tracing efforts related to COVID-19;

• provide simultaneous testing for TB and COVID-19 for individuals when indicated, including by leveraging TB laboratory networks and platforms; and

• ensure proactive planning and budgeting for both conditions (including for the catch-up phase), procurement of supplies and risk management.

Content related to TB has also been included in WHO guidance on maintaining essential health services and the role of community-based care during the COVID-19 pandemic (14, 15).

The top priority for the rest of 2021 and 2022 is to try to restore access to and provision of essential TB services such that levels of TB case detection can recover to at least 2019 levels.