Aside from the direct changes to daily life necessitated by COVID-19, the pandemic also has other serious impacts on other programs and initiatives around the world. In medicine, a “syndemic” is defined as “the convergence of two or more diseases that act synergistically to magnify the burden of disease”. The interaction between human immunodeficiency virus (HIV) and tuberculosis (TB) is an exemplary case with deadly consequences for many of those infected around the world.
In 2008, it was estimated that 33.4 million people were living with HIV worldwide. Of this population, 30% were estimated to have latent or active TB infection. In 2019, this number has grown to approximately 38 million and co-infection remains among the leading causes of death for people living with HIV (PLHIV). Despite this, prior to the beginning of the pandemic, many nations were making steady advancements and five lower- or middle-income countries have already exceeded the target of a 75% reduction in TB deaths among PLHIV.
Data and Clinical Characteristics of HIV-TB
HIV infection is divided into three progressive stages: (1) acute HIV infection, (2) chronic HIV infection, and (3) Acquired Immunodeficiency Syndrome (AIDS). Note that characteristic symptoms of the disease during the first stage–night sweats, fatigue, chills, fevers, and rashes–are often mistaken as the flu or a bad cold. However, it is during this period where patients are most contagious due to high viral load. HIV eventually goes into clinical latency in the second phase, but returns at the end as the patient moves into stage three. It is during this period where antiretroviral medicines (ART) can arrest disease progression, allowing those infected to lead nearly-normal lives.
In contrast to HIV, TB is caused by the Mycobacterium tuberculosis bacteria and can affect many organs in the body despite primarily manifesting in the lungs. It is also divided into two kinds: (1) latent and (2) active. In the former condition, the person is infected but the bacteria are inactive–only when they develop into the latter condition do symptoms manifest and the person becomes infectious. Symptoms of the disease include coughing, fever, night sweats, and pain in the affected area (most often the chest). As transmission depends on microscopic droplets in the air, it is enhanced in areas with high population density or when people are required to be in close contact.
It is important to note that TB is an opportunistic infection. Indeed, people with HIV are 18 times more likely to get TB or advance to the active stage of the disease due to a weakened immune system. On average, without treatment, 45% of HIV-negative and nearly all HIV-positive people with TB die.
Control of HIV-TB Syndemic Prior to COVID-19
Aside from co-infection with HIV, people with undernutrition are also three more at risk of developing TB than a health person. Thus, the overlap of risk factors generates a wicked problem for healthcare programmers. In spite of this, the launching of the President’s Emergency Plan for AIDS Relief (PEPFAR) represents a huge step in global health and has proven instrumental in providing economic support for programs all around the world. In the latest UNAIDS Tuberculosis and HIV report, it was estimated that global TB deaths among PLHIV have fallen by 42% since 2010. The World Health Organisation (WHO) recommended “Six I’s” of reducing TB among people living with HIV are: (1) intensified case-finding, (2) isoniazid preventive therapy, (3) infection control, (4) TB/HIV integration, (5) initiating ARV treatment, and (6) involvement of the community. Joint HIV/TB programs provide care in a variety of settings including at home, in community clinics, and in larger hospitals. Main goals include: (1) increasing knowledge of HIV status, starting antiretroviral treatment (ART), (3) starting co-trimoxazole preventative (CPT) therapy, and (4) providing antibacterial drugs to those who have already developed to the active stage of TB.
Though a vaccine that is partially effective against TB, the bacillus Calmette-Guerin (BCG), exists, it is not recommended for general use in the United States because it is not very effective in adults.
Impact of COVID-19 on Testing and Treatment Programs
Historically, diagnosis of TB relied heavily on cultures and sputum smear microscopy. GeneXpert, a new self-contained testing unit that does not require a sophisticated laboratory set-up, accelerates this process. This same equipment is currently being used to detect COVID-19 infections in lower-and middle-income countries (LMIC). Treatment providers and recipients alike report decreased support and funding as well as increased barriers to accessing treatment such as lockdowns, disrupted supply lines, and fear of infection from coming into contact with other people. The result is lack of testing and identification of new cases as well as the disruption of treatments in progress.
In the short term, failing to adhere to the drug regimens for HIV and TB increases susceptibility to illness in the short term. An even deadlier consequence looms in the future–drug resistance. Sporadic treatment applies selective pressure to both bacilli and viruses, producing strains that become increasingly unaffected by the current treatments available until no more drugs or available or what is currently available is too expensive.
In September of 2020, a New York Times article warned of “the biggest monster” that is not coronavirus. It went on to describe the ways in which the pandemic has served to divert scientific and political attention from TB, HIV, and malaria and threaten recent progress by raising insurmountable barriers to regular programs. The article cites estimates from the Stop TB Partnership, WHO, and the Global Fund that paint a bleak picture–a potential 6.3 million increase in TB cases, 1.4 million associated deaths, and 500,000 additional AIDS-related deaths. While infrastructure built to diagnose HIV and TB have been extremely helpful for allowing quick response to coronavirus testing, it is not used to cover all possible bases and its original purpose is neglected. The drop in diagnoses carries an unpayable price tag of at least $28.5 billion USD. Thus, it is crucial to consider how HIV-TB treatment can be restarted as soon as possible and integrated with COVID-19 programming in a way that does not disrupt progress towards eliminating either disease.
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