2.1 Case notifications
Tuberculosis (TB) case notifications refer to people diagnosed with TB disease and officially reported as a case to national authorities. Case notification data have been systematically collected at national level and then reported to WHO on an annual basis since the mid-1990s, based on standard case definitions and associated guidance on the recording and reporting of data provided by WHO. A new edition of WHO guidance on TB surveillance is scheduled for publication before the end of 2023 (1).
Globally in 2022, 7.5 million people with a new episode of TB (referred to as new and relapse cases) were diagnosed and notified (Table 2.1.1). Of these, 83% had pulmonary TB and 17% had extrapulmonary TB. Collectively, the WHO African, South-East Asia and Western Pacific regions accounted for almost 90% of total notifications, with close to half in the South-East Asia Region alone.
| WHO region | Total notified | New and relapsea | Pulmonary new and relapse number | Pulmonary new and relapse bacteriologically confirmed (%) | Extrapulmonary new and relapse (%) | People living with HIV, new and relapse | MDR/RR-TB onlyb | pre-XDR-TB or XDR-TBc |
|---|---|---|---|---|---|---|---|---|
| African Region | 1 779 573 | 1 746 536 | 1 527 151 | 67% | 13% | 307 125 | 21 402 | 1 093 |
| Region of the Americas | 258 007 | 239 987 | 207 873 | 79% | 13% | 21 033 | 5 136 | 292 |
| South-East Asia Region | 3 722 589 | 3 550 243 | 2 820 705 | 62% | 21% | 63 457 | 68 399 | 13 568 |
| European Region | 185 758 | 158 324 | 133 564 | 71% | 16% | 20 029 | 25 015 | 9 424 |
| Eastern Mediterranean Region | 579 795 | 573 401 | 446 130 | 56% | 22% | 1 745 | 5 124 | 1 149 |
| Western Pacific Region | 1 212 133 | 1 182 766 | 1 086 028 | 59% | 8% | 13 569 | 24 435 | 1 549 |
| Global | 7 737 855 | 7 451 257 | 6 221 451 | 63% | 17% | 426 958 | 149 511 | 27 075 |
b RR-TB, rifampicin-resistant TB; MDR-TB, multidrug-resistant TB (defined as TB that is resistant to rifampicin and isoniazid). This column excludes any cases with known resistance to any fluoroquinolone.
c XDR, extensively drug-resistant TB. Pre-XDR-TB is defined as TB that is resistant to rifampicin and to any fluoroquinolone. XDR-TB is TB that is resistant to rifampicin and to any fluoroquinolone, and to at least one of bedaquiline or linezolid.
In 2020 and 2021, disruptions associated with the coronavirus (COVID-19) pandemic had a substantial impact on TB case notifications (Fig. 2.1.1). Globally, the number of people newly diagnosed with TB and notified fell from 7.1 million in 2019 to 5.8 million in 2020 (-18%), in marked contrast to large increases between 2013 and 2019. There was then a partial recovery to 6.4 million in 2021. The 7.5 million people newly diagnosed and notified with TB in 2022 is both a rebound to above the pre-COVID level and the highest number for a single year since WHO started to compile data. The big increase from 2020–2021 levels shows that there has been a good post-COVID recovery in access to and provision of health services in many (but not all) countries; it also likely reflects diagnosis of a backlog of people who developed TB in previous years but whose diagnosis was delayed due to COVID-related disruptions and an increase in the number of people falling ill with TB (Section 1.1).
Trends in case notifications in the six WHO regions before, during and in the aftermath of the COVID-19 pandemic vary (Fig. 2.1.2). The pattern in the South-East Asia Region was very similar to the global trend, with a big reduction (-24%) between 2019 and 2020 followed by a partial recovery in 2021 and then a rebound to above the pre-COVID level in 2022; indeed, it is this region that drove the trend at global level. There was a comparable pattern in the Region of the Americas. Notifications in the Eastern Mediterranean Region had already recovered to 2019 levels in 2021, with a further increase in 2022 (mostly influenced by trends in the country with the highest burden of TB in the region, Pakistan). In the European Region, notifications fell at a rate above the historic trend in 2020, increased in 2021 (likely representing some backlog from 2020) and then fell. In the Western Pacific Region, there was a big drop in case notifications in 2020, a further fall in 2021 and a small increase in 2022. However, trends in the Western Pacific Region were driven by China, which accounted for just over half (51%) of total notifications in the region in the four years 2019-2022, and where notifications have been declining consistently for several years (Fig. 2.1.3). In most countries in this region, including three of the other high TB burden countries (Cambodia, the Philippines, Viet Nam), case notifications fell in either 2020 or 2021 but then recovered to 2019 levels (or beyond) in 2022 (Fig. 2.1.3). It was striking that notifications in the African Region increased throughout the pandemic, suggesting that any COVID-related disruptions had no or limited impact on TB case detection.
At country level, the 30 high TB burden and three global TB watchlist countries can be categorized into six groups, according to the timing and degree of disruptions to TB notifications during the COVID-19 pandemic and subsequent patterns of recovery in its aftermath (Fig. 2.1.3). The biggest group consists of 13 countries in which there were major reductions in TB case notifications in 2020 or 2021, followed by a rebound to 2019 levels or beyond in 2022 (Fig. 2.1.3a). In a further six countries, there were reductions between 2019 and 2021, followed by a partial recovery in 2022 (Fig. 2.1.3b). Nine countries reported either increased notifications throughout the pandemic and its aftermath or declines that were consistent with historic trends, suggesting no or only limited COVID-related disruptions to TB case detection (Fig. 2.1.3c, Fig. 2.1.3d). The countries in these two groups were mostly in the African Region, consistent with the regional data shown in Fig. 2.1.2. Five countries had unusual patterns that are difficult to explain: either a reduction in 2020, an apparent recovery in 2021 and then a reduction in 2022 (Fig. 2.1.3e); or a decline consistent with historic trends during the main years of the pandemic (2020 and 2021) followed by an increase in 2022 that was in stark contrast to pre-2022 trends (Fig. 2.1.3f).
(a) Negative impact in 2020a or 2021, recovery to 2019 levels or beyond in 2022
(b) Negative impact in 2020a–2021, partial recovery in 2022
Patterns of impact and recovery in 2020, 2021 and 2022, in percentage terms and relative to the baseline of 2019, are shown for the 30 high TB burden and three global TB watchlist countries in Fig. 2.1.4. As highlighted in previous global TB reports (2, 3), the countries with the largest relative reductions in either 2020 or 2021 were (ordered according to the size of the relative reduction) Myanmar, the Philippines, Mongolia, Lesotho, Indonesia, Cambodia, Zimbabwe, India, Viet Nam and Bangladesh (all >20%).
Globally, the cumulative total number of people diagnosed with TB and officially reported from 2018 to 2022 was 34 million, 84% of the 5-year target of treating 40 million people between 2018 and 2022 that was set at the UN high-level meeting on TB in 2018 (Fig. 2.1.5). This included 2.5 million children, 71% of the five-year target of 3.5 million. A cumulative total of 824 988 people were treated for multidrug or rifampicin-resistant TB (MDR/RR-TB), 55% of the five-year target of 1.5 million. This included 21 625 children, only 19% of the five-year target.
Most notified cases of TB are among adults (Fig. 2.1.6). Of the global total of people with a new or relapse episode of TB who were notified in 2022, 56% were men, 35% were women and 8.2% were children aged 0–14 years (the age groups related to children for which WHO routinely collects data are 0–4 and 5–14 years; it is recognized that the second category includes young adolescents). For the remainder, either age or sex were unknown. In general, notification data appear to understate the share of the total TB disease burden that is accounted for by men, since higher M:F ratios among adults have been found in national TB prevalence surveys (Section 1.4). The drop in case notifications between 2019 and 2020 and subsequent recovery was similar for men and women, while both the drop in 2020 and subsequent recovery were more pronounced for children.
Although the global proportion of notified cases accounted for by children aged 0–14 years has been relatively stable (Fig. 2.1.6), there is considerable variation at country level (Fig. 2.1.7). There are recognized issues with the diagnosis and reporting of TB in children, including the use of variable case definitions and underreporting of cases diagnosed by paediatricians in the public and private sectors. Greater attention to the quality of TB notification data for children is warranted in many countries.
There is also considerable country variation in the proportion of notified cases diagnosed with extrapulmonary TB (Fig. 2.1.8). This may reflect underlying differences in TB epidemiology as well as diagnostic practices.
There is striking country variation in the distribution of TB case notifications according to country of origin (Fig. 2.1.9). In several countries with a low incidence of TB, more than 75% of notified cases were among people of foreign origin.
Engagement of all care providers in the public and private sectors through public–private mix (PPM) initiatives can help to minimize the underreporting of people diagnosed with TB. Since 2015, the contribution of such initiatives to total notifications has grown in most of the seven countries defined as top global priorities for PPM (Fig. 2.1.10). Detailed data for 18 other countries are available in the online WHO global TB database.
b Public-public mix refers to engagement by the NTP with public health sector providers of TB care that are not under the direct purview of the NTP. Examples include public hospitals, public medical colleges, prisons and detention centres, military facilities, and public health insurance organizations.
Community engagement can help with referrals of people with TB symptoms to health facilities as well as treatment support; in 80 countries from which WHO requested data in 2022, such engagement was reported in a high proportion of basic management units (Fig. 2.1.11).
Case-based digital surveillance systems enable timely reporting and use of TB data. In 2022, 135 countries and areas that collectively accounted for 65% of officially notified TB cases were using a case-based digital surveillance system that covered all people diagnosed with TB (Fig. 2.1.12). This was similar to the level of 2021, when 134 countries and areas that collectively accounted for 67% of officially notified TB cases were using such systems. Acceleration of progress in making the transition from paper-based reporting of aggregated TB data to case-based digital TB surveillance is particularly needed in the African Region. The latest WHO guidance on TB surveillance (1) gives specific attention to the establishment or strengthening of case-based digital TB surveillance.
Further country-specific details about TB case notifications are available in the Global tuberculosis report app and country profiles.
Data shown on this webpage are as of 21 July 2023 (see Annex 2 of the main report for more details).
References
Guidance on tuberculosis surveillance. Geneva: World Health Organization; 2023 (in press).
Global tuberculosis report 2021. Geneva: World Health Organization; 2021 (https://iris.who.int/handle/10665/346387).
Global tuberculosis report 2022. Geneva: World Health Organization; 2022 (https://iris.who.int/handle/10665/363752).