World AIDS Day (1st December)
Editor: Dr. Praful B. Godkar (Ph.D)
Eminent Author, Medical Biochemist and Scientist, Technical Education consultant.
AGD Biomedicals (Pvt) LTD. Andheri East, Mumbai.
Effective use of advanced lVD laboratory tests and Post-Exposure Prophylaxis (PEP) in the past two decades have significantly decreased the total number of AIDS patients in India(1). The objectives of World AIDS Day 2024 are to spread awareness about the status of the HIV-epidemic and encourage progress in HIV prevention, treatment, and care around the world(2). IVD laboratory staff members, healthcare workers and allied professionals are at high risk of exposure to HIV. The Centers for Disease Control and Prevention recommends at least once a year HIV screening tests, if a person is engaged in activities that can transmit HIV infection(3,4). Strategies such as abstinence, not sharing needles, and using condoms correctly are methods to prevent HIV. Medical treatments such as pre-exposure prophylaxis (PrEP) and post-exposure prophylaxis (PEP) are other strategies used to prevent HIV. Both PrEP and PEP are highly effective for preventing HIV(5).
Q1. What are the basic screening laboratory tests for HIV detection?
ANS: ELISA is recommended screening test. If ELISA test is uncertain, repeat positive test is confirmed using Western Blot (WB) test or RT-PCR(6).
Q2. What is the importance of determination of HIV-viral-load?
ANS: HIV-viral-load determination is important to monitor the effects of the treatment of drug combinations, monitor treatment decisions, the status of HIV infection, and reduce the risk of HIV transmission(6).
Q3. which test is used to determine HIV viral load?
ANS: RT-PCR(6).
Q4. What specific biomarkers are used in IVD laboratory tests and how do these contribute to precise diagnosis?
ANS:
(1) A CD4 T lymphocyte cell count (Normal range: 500-1,500 cells/microliter) or a CD4 T lymphocyte cell percentage of total lymphocytes (Normal range 28-58%). Decrease in CD4 lymphocytes indicate rapid progression of HIV infection(6).
(2) Ratio of CD4 T lymphocyte cells and CD8 T lymphocyte cells (Normal ratio: 1.2-3.3). Change of ratio with decrease in CD4 lymphocytes indicate rapid progression of HIV infection(6).
(3) A CD3 T lymphocyte cell count (Normal range: 655-2800 cells/microliter). A decrease in CD3-positive T-cell count is a predictive factor of AIDS development in HIV-1 infected adults, children and infants(7).
Q5. What is the CDC Classification system for HIV infection?
- A CD4 T lymphocyte cell count below 200 cells/µl (or a CD4 T lymphocyte cell percentage of total lymphocytes of less than 14%) OR
- Patient has one of the following defining illnesses: Candidiasis of bronchi, trachea, or lungs, Cervical cancer (invasive), Herpes simplex, Chronic ulcers for more than 1 month. Prolonged illness related to the following clinical conditions: Bronchitis, Pneumonitis, Esophagitis, Histoplasmosis (disseminated or extrapulmonary), Cytomegalovirus disease (other than liver, spleen or lymph nodes), Kaposi’s sarcoma, Cryptococcosis, (extrapulmonary), Coccidioidomycosis (disseminated or extrapulmonary), Mycobacterium tuberculosis, Burkitt’s lymphoma, Mycobacterium avium complex, Salmonella sepsis (recurrent), Toxoplasmosis of the brain, Pneumocystis carinii pneumonia, Encephalopathy, etc.
Q6. What is Post-exposure prophylaxis (PEP)?
ANS: Post-exposure prophylaxis (PEP) means taking infection preventing PEP as soon as possible (ASAP), after a possible exposure to a specific infection like HIV or hepatitis B.
Q7. What is PEP to prevent HIV infection?
ANS: Post-exposure prophylaxis, is a short course of HIV medicines taken very soon after a possible exposure to HIV to prevent the virus from infecting an individual. Patient must start it within 72 hours after exposed to HIV, since HIV is not curable, however, it is 100% preventable. PEP is recommended in the following situations:
- Patient may have been exposed to HIV during sex.
- Patient may have got needle-stick while handling blood specimen.
- Patient was sexually assaulted.
Q8. What are PEP medicines?
- PEP medicines may cause side effects. These side effects can be treated and are not life-threatening.
- PEP medicines may interact with other medicines.
Q9. What is the worldwide prevalence of HIV and how does PrEP and PEP impacted the decline in the total number of HIV cases in India?
ANS: As of the end of 2023, the global prevalence of HIV was 39.9 million people, which is about 0.6% of adults aged 15–49(1). The WHO African Region remains most severely affected, with one in every 30 adults (3.4%) living with HIV and accounting for more than two-thirds of the people living with HIV worldwide(1). According to the India HIV Estimations 2023 report, the adult HIV prevalence in India is 0.2%. This is a decline from the peak of 0.55% in 2000(1) due to the effective implementation of PrEP and PEP.
References
(1) Global HIV & AIDS statistics—Fact sheet UNAIDS. Accessed 4 December 2021.
(2) “About World Aids Day”. worldaidsday.org. National Aids Trust. Archived from the original on 20 November 2015. Retrieved 4 December 2014.
(3) CDC. Acquired immunodeficiency syndrome (AIDS): Precautions for clinical and laboratory staffs. MMWR 1982;31:577-80.
(4) CDC. Acquired immunodeficiency syndrome (AIDS): Precautions for health-care workers and allied professionals. MMWR 1983;32:450-1.
(5) Vontrese McGhee, MBA, Director, Office of HIV Prevention and Care, Alabama Department of Public Health, The RSA Tower, Suite 1200, 201 Monroe Street Montgomery, Alabama 36104.
(6) Godkar PB, Godkar DP. Text book of Medical laboratory technology (4th edition, 2024), Bhlani Publishers, Mumbai. India.
(7) Herman Mendez MD, William T. Shearer MD, PhD. Decline of CD3-positive T-cell counts by 6 months of age is associated with rapid disease progression in HIV-1–infected infants. Journal of Allergy and Clinical Immunology, Volume 108, Issue 2, August 2001, Pages 265-268.
