By Harika Palabatla
Hyderabad: Human immunodeficiency virus (HIV) constitutes the major burden of infectious diseases globally. HIV attacks the immune system and weakens the defence against many infections which people with healthy immune systems can easily combat. According to National Aids Control Organisation (NACO) India HIV Estimates 2021 report, 41,968 people died due to AIDS-related deaths in 2021 and a sum of 24,01,284 people are living with HIV in India.
Being a highly contagious disease, HIV has been one of the major concerns in India. The growing prevalence of HIV is also increasing the growth of HIV drug markets. With growing advances in the development of effective HIV treatments, people living with HIV (PLHIV) are able to suppress the effects of the virus and avoid transmitting it to others. Commenting on the new developments in HIV cure, Prashant Khadayate, Director, Lifesciences Consulting and Research, GlobalData said, “A total of 18 gene/cell therapy candidates are in the development process for HIV eradication and making it a curable disease. The National Institute of Allergy and Infectious followed by Johnson & Johnson is working on the development of effective vaccines for HIV prevention. Pharma companies namely ViiV Healthcare (GSK company) and Gilead Sciences are in the race to develop broadly neutralising antibodies and long-acting therapies for HIV. The data also suggests that HIV cases treated with drug therapy in India are estimated to grow at a CAGR of 1.74 per cent, from 1.75 million in 2021 to 1.93 million in 2029.”
Though many innovations in the form of drugs, vaccines, antibodies and therapies are being developed for the disease, the mortality rates of the virus are still challenging. According to World Health Organisation (WHO), Global TB 2020 report TB remains the leading cause of death among PLHIV. PLHIV are 18 times more likely to develop active TB disease than people without HIV. In 2019, of the estimated 10 million (range, 8.9–11.0 million) people who developed TB worldwide, 8.2 per cent were PLHIV. Even when on antiretroviral therapy (ART), PLHIV are three times more likely to die during TB treatment, and continue to suffer disproportionately. As HIV attacks the immune system and makes it susceptible to other infectious diseases such as TB. HIV coinfection with TB cases is seen rising globally. This co-infection is resulting in many challenges such as patient compliance, drug interactions, overlapping toxic effects, and risk of immune reconstitution inflammatory syndrome (IRIS).
Early signs of HIV-TB coinfection
HIV-infected individuals appear to be more likely to acquire TB if exposed to Mycobacterium tuberculosis. Although an HIV patient can suffer from TB at any point of time, the risk increases with the depletion of the T-helper cells with the progression of the HIV disease, due to declining immunity.
Speaking to ETHealthworld Dr Surabhi Madan, Consultant, Infectious diseases, Marengo CIMS, Ahmedabad, said, “When HIV patients who are stable on antiretroviral treatment (ART), develop new onset constitutional symptoms like fever, weight loss, night sweats, decrease in appetite, generalised weakness and lethargy, should be investigated for TB. TB can affect almost any organ of the body. The site-specific symptoms depend on the organ of involvement due to TB. A patient with pulmonary TB presents with a cough that may be associated with breathlessness; a patient with pericardial TB may have chest pain and breathlessness on exertion. Abdominal pain, vomiting, constipation or diarrhoea may be the manifestations of intestinal TB; headache, vomiting, and altered sensorium may be the presenting features of TB affecting the brain.”
HIV-TB co-infection challenges
HIV co-infection with TB leads to challenges in both the diagnosis and treatment of TB. Due to the overlap of the symptoms, the diagnosis of TB may get delayed, which may affect the outcome of treatment, in addition to that as both infections attack the immune system, there is an increased risk of IRIS which can lead to severe complications and difficult-to-control disease.
Commenting on the challenges with HIV-TB Coinfection Dr Manoj Goel, Director, Pulmonology, Fortis Memorial Research Institute, Gurugram said, “TB in HIV may be difficult to diagnose initially which leads to delay in initiation of treatment. There is an increased risk of infection in other organs brain, spine and kidneys besides the lungs. The risk of multidrug and extremely drug-resistant tuberculosis in HIV is much higher. The side effects of anti-tubercular drugs are likely to be more. The risk of treatment failure for both TB and HIV is higher.”
Adding to this, Dr Madan said, “The diagnosis of TB in HIV patients who are treatment naïve (yet not started on ART) is a challenge. This is because the constitutional symptoms of both diseases are similar. Hence many clinicians opt to investigate thoroughly, with the help of investigations like CT scans, to rule out coexisting TB before starting the patient on ART. This is necessary because treatment of TB (AKT) should always be begun earlier than ART to avoid the risks associated with immune reconstitution-related unmasking or worsening of clinically undiagnosed or unrecognised TB, which could be life-threatening.
The other important challenge in HIV and TB coinfection is the role of TB on HIV progression. Elucidating this, Dr Madan said “In HIV patients, TB appears to increase the risk of progression to AIDS or death. The acceleration may occur due to a significant increase in HIV viremia, and generalised immune activation leading to increased levels of the CD4+ cells and receptors, which are the target sites for HIV. The mortality rate in patients coinfected with HIV and TB is higher as compared to patients suffering from HIV without TB.”
Early detection is key
As the constitutional symptoms of HIV and TB are similar, early detection of TB is always a challenge. According to the WHO Global Tuberculosis Report 2022 globally, 44 per cent of people with HIV-associated TB were not diagnosed in 2019. Autopsy studies among individuals who had died from AIDS report that almost half (46 per cent) of them had TB that had not been detected prior to death. Enhancing the detection of TB among people living with HIV is therefore critical.
Speaking on the early identification of TB among HIV patients, Prof Preeti Kumar, Director, IIPH, Delhi and Vice President, PHFI said, “Thus prevention becomes an important pillar of reducing TB in HIV patients. It is important to treat all cases of latent and active TB, among HIV patients. The first step is to screen people living with HIV for TB. All PLHIV (adults, adolescents and children more than one-year-old) should be given TB preventive treatment (TPT). Simultaneously every effort needs to be made to trace and screen all contacts of people who are receiving TPT. Additional interventions in the form of nutritional support, access to regular treatment and ensuring adherence and completion of TPT are essential to reduce the risk of TB among HIV patients.”
With increasing access to effective prevention, diagnosis, treatment and care, HIV has become a manageable chronic health condition, but the incidence of TB has been concerning due to increased mortality rates. So, early identification and preventive measures are key to decreasing the risk of TB prevalence in HIV patients.