The Covid-19 pandemic affected health systems worldwide, and its impact is now being felt on the infectious disease, tuberculosis (TB), caused by the bacterium Mycobacterium tuberculosis. The pandemic has impeded access to TB care, both directly via drug and clinic access, and indirectly via loss of funding and resources, as described by the World Health Organization (WHO) 2021 Global Tuberculosis Report. GlobalData epidemiologists expect a temporary decrease in diagnosed incident cases of TB and a temporary increase in TB deaths resulting from the Covid-19 pandemic across the 16 major pharmaceutical markets (16MM: US, France, Germany, Italy, Spain, UK, Japan, Australia, Brazil, Canada, China, India, Mexico, Russia, South Africa, and South Korea).
According to the WHO Global TB report, newly reported TB cases dropped from 7.1 million in 2019 to 5.8 million in 2020, an 18% decline. This was associated with consequences of the Covid-19 pandemic such as lockdowns, fear of leaving home, reduction in healthcare capacity, and confusion between TB and Covid-19 symptoms. This reduction in case reporting increased the discrepancy between reported cases and estimated TB incident cases. In the 16MM, GlobalData epidemiologists forecast that diagnosed incident cases of TB will increase from 3.6 million cases in 2022, to 3.8 million cases in 2027. However, the impact of Covid-19 on both the global population and on healthcare access and mortality rates may result in diagnosed incident cases falling below current forecast estimates. It is unclear how much time will be required for these metrics to return to pre-pandemic levels as case reporting catches up.
TB mortality was also affected by the pandemic. TB was the leading cause of infectious disease deaths until 2020, when it was deposed by Covid-19. Even so, global TB deaths increased during the Covid-19 pandemic in 2020, marking the first increase in TB mortality since 2005. In fact, TB mortality returned to 2017 levels, with 1.5 million TB deaths. The WHO predicts that global TB mortality will not return to previously expected levels until at least 2024.
The changes in TB mortality are more abrupt and dramatic than TB incidence for a variety of reasons. The onset of TB is very slow, so delay in diagnosis is not as urgent as delay or disruption in treatment. Disruptions in antibiotic access also affected treated cases more strongly than undiagnosed cases because antibiotic non-compliance can lead to increased risk of drug-resistant TB. Decreased income also affects likelihood to seek treatment but not mortality.
Logistic impacts of the Covid-19 pandemic may perpetuate barriers to appropriate care and exacerbate TB under-reporting and mortality in upcoming years. This includes physical impediments, like supply delays, funding insufficiency, and decreased income, and nutrition levels of populations globally. This impact can be ameliorated by focusing public health efforts on re-establishing medical access to remote areas, and increasing emphasis on major infectious diseases like TB.