Acquired Immunodeficiency Syndrome (AIDS)

AIDS is a chronic, potentially life-threatening condition caused by the human immunodeficiency virus. Know more about the causes, symptoms and treatment.

Overview

According to UNAIDS, by the end of 2024, approximately 40.8 million people were living with HIV globally. In 2024, approximately 1.3 million people were newly infected with HIV, and around 630,000 deaths occurred due to AIDS-related illnesses.

The African continent has the highest number of people affected. Currently, AIDS is described as a pandemic, a disease which has spread across continents.

People in developing countries are most affected, as HIV infection increases the chances of acquiring infections like tuberculosis and dying due to AIDS-related complications.

AIDS also affects the economy of the country because a majority of the individuals affected are in the productive age group.

Globally, 87% of people living with HIV knew their status in 2024, 77% were accessing antiretroviral therapy, and 73% had achieved viral suppression.

HIV/AIDS in India

According to NACO (National AIDS Control Organisation) and the India HIV Estimates 2025 Technical Report, India’s adult (15–49 years) HIV prevalence stands at approximately 0.20%, significantly lower than the global average of 0.7%.

New HIV infections in India declined by 49% from approximately 1.25 lakh in 2010 to an estimated 64,500 in 2024.

AIDS-related deaths in India have declined by over 81% from 1.73 lakh in 2010 to approximately 32,200 in 2024.

Over 18 lakh people living with HIV in India are currently receiving free antiretroviral treatment through government-supported ART centres, with 94% ART retention and 97% viral suppression rates.

India produces approximately 70% of the global supply of generic antiretroviral drugs, making affordable treatment accessible both domestically and worldwide.

Causes

AIDS is caused by the human immunodeficiency virus (HIV). These viruses are called retroviruses and belong to a genus called Lentivirus.

There are two types of HIV: HIV-1 and HIV-2.

HIV-1 is the most common virus present worldwide. It accounts for 95% of all the infections. HIV-1 has several subgroups, M, N, O, and P. Among these, subgroup M is the most widely prevalent.

HIV-2 is less commonly prevalent. It has been reported from Western Africa, European countries like Portugal and France and India. It causes disease which progresses slower than that caused by HIV-1.

HIV can be transmitted through:

• Unprotected sex with an infected person
• Sharing of infected needles between illicit drug users
• Transfusion of infected blood to an uninfected person
• From an infected mother to her unborn child during pregnancy, delivery, or breastfeeding

Symptoms

HIV infection progresses through three stages:

Stage 1: Acute HIV Infection

Within 2 to 4 weeks of exposure, some individuals experience flu-like symptoms including fever, headache, muscle aches, sore throat, swollen lymph nodes, and skin rash.

This is the body’s initial response to HIV infection. During this stage, the virus multiplies rapidly and the person is highly infectious.

Stage 2: Clinical Latency (Chronic HIV Infection)

During this stage, HIV is still active but reproduces at very low levels.

Individuals may not have any symptoms or may experience only mild ones.

Without treatment, this stage can last a decade or longer, but some people may progress faster.

Towards the end of this phase, the viral load increases and the CD4 cell count declines.

Stage 3: AIDS

AIDS is the most severe stage of HIV infection. The immune system is badly damaged, making the person vulnerable to opportunistic infections and cancers.

A person is diagnosed with AIDS when their CD4 cell count falls below 200 cells/µL, or when they develop certain opportunistic illnesses.

Without treatment, people with AIDS typically survive about 3 years.

Common symptoms at this stage include:

• Rapid weight loss (wasting syndrome)
• Recurring fever and profuse night sweats
• Extreme and unexplained fatigue
• Prolonged swelling of lymph nodes
• Prolonged diarrhoea
• Sores of the mouth, anus, or genitals
• Pneumonia
• Neurological complications including confusion, forgetfulness, and walking abnormalities (AIDS dementia complex)

Risk Factors

Lack of adequate knowledge about HIV and its modes of transmission is the primary factor that increases the chances of exposure to HIV.

Infection with HIV can occur in any individual regardless of their sexual orientation, race, gender, occupation or social status.

However, certain practices and lifestyle behaviours may increase the likelihood of acquiring HIV infection.

These practices are called risk factors because they increase the risk of HIV infection.

Unsafe or Unprotected Sex

Unsafe sex is the leading risk factor for acquiring HIV infection.

When you engage in unsafe vaginal, oral, or anal intercourse with an infected person, exchange of body fluids that contain HIV occurs.

The virus enters your body from the sexual fluids.

The risk of AIDS is very high in an individual who has multiple sex partners as it increases the probability of having intercourse with an infected individual.

Sexually Transmitted Diseases (STDs)

Presence of sexually transmitted diseases such as syphilis, herpes, and gonorrhoea increases the risk of contracting HIV as it causes changes in genital tissues and increases the susceptibility of HIV transmission.

Unsafe Injection Practices

Unsafe injection practices involve using the same syringe, needle or injection equipment among multiple individuals.

This practice is common among illicit drug users who share needles.

According to current WHO estimates, unsafe medical injections account for approximately 2% of new HIV infections globally, a significant reduction from earlier decades due to improved injection safety programmes.

However, the risk remains substantially higher among people who inject drugs, who have 35 times the risk of acquiring HIV compared to the general population.

Blood Transfusion

Receiving a transfusion of infected blood or blood products can transmit HIV.

In many countries, including India, mandatory screening of donated blood for HIV has greatly reduced this risk.

Mother-to-Child Transmission

An infected mother can pass the virus to her child during pregnancy, labour, delivery, or through breastfeeding.

Antiretroviral treatment during pregnancy significantly reduces this risk.

Occupational Exposure

Healthcare workers may be at risk through accidental needle-stick injuries with HIV-contaminated needles or sharps.

Diagnosis

Window period of HIV is the period that immediately follows the initial infection with HIV during which the infection is not detected by the tests used.

During the window period, the patient is highly infectious but the tests for HIV are negative.

Most people develop antibodies to HIV between 3 to 12 weeks of infection.

For fourth-generation ELISA, the window period is usually 4 weeks.

Viral load tests may detect HIV nucleic acid by an average of 14 days.

Due to the window period, if the test for HIV is initially negative following exposure, the test must be repeated after 2–3 months.

The following tests are used to diagnose HIV infection:

ELISA (Enzyme-Linked Immunosorbent Assay)

It is a blood test that detects the presence of HIV antibodies in the blood.

It is the most commonly used screening test for HIV.

Fourth-generation ELISA tests can also detect the p24 antigen, allowing earlier detection.

HIV-Chemiluminescent Assay

This is a variation of HIV-ELISA and is performed using automated instruments.

These tests are highly sensitive and use the principle of chemiluminescence.

Western Blot

It is a blood test used to detect multiple HIV antibodies in the blood.

The procedure for the western blot test requires a strip containing a series of proteins on a specialised blotting paper.

The blood sample is made to react with the paper strip.

An enzyme is used to cause colour change and detect antibodies.

If the person is HIV infected, several coloured bands appear on a strip.

Viral Load Test

It is used to monitor the treatment progress or detect early HIV infection.

It measures the amount of HIV present in your blood.

It can be done using methods that detect the genetic material of the virus.

These include reverse transcription-polymerase chain reaction (PCR), branched DNA assay (bDNA) and nucleic acid sequence-based amplification assays (NASBA).

Treatment

Antiretroviral therapy (ART) is the standard treatment for HIV/AIDS.

Modern ART typically uses a combination of drugs from different classes to suppress the virus effectively and prevent resistance.

ART must be taken lifelong.

Although there is no cure for HIV, medications can suppress the virus to undetectable levels, allowing people living with HIV to lead long, healthy lives.

First-Line Treatment (WHO and NACO Recommended)

Integrase strand-transfer inhibitors (INSTIs): Dolutegravir (DTG) is the preferred first-line anchor drug globally and in India (per NACO 2021 guidelines). Other INSTIs include raltegravir and bictegravir.

Nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs): These form the backbone of most ART regimens. Examples include Tenofovir disoproxil fumarate (TDF) or Tenofovir alafenamide (TAF), Lamivudine (3TC), Emtricitabine (FTC), Abacavir (ABC), and Zidovudine (AZT).

The current WHO-recommended first-line regimen for adults is: Dolutegravir + Tenofovir + Lamivudine (DTG + TDF + 3TC).

Other ART Drug Classes

• Non-nucleoside reverse transcriptase inhibitors (NNRTIs): Efavirenz, Nevirapine.
• Protease inhibitors (PIs): Atazanavir/ritonavir, Darunavir/ritonavir.
• Entry/fusion inhibitors: Enfuvirtide, Maraviroc.
• Post-attachment inhibitors and capsid inhibitors: These are newer drug classes developed for treatment-resistant HIV.

Treatment Outcomes

With consistent ART adherence, people living with HIV can achieve undetectable viral loads, maintain healthy immune function, and have near-normal life expectancy.

An important principle in modern HIV care is Undetectable = Untransmittable (U=U): people with a sustained undetectable viral load do not transmit HIV to sexual partners.

ART is also used to prevent the transmission of HIV infection from an infected pregnant mother to the baby.

For this reason, the WHO advises all pregnant women to be tested for HIV.

Additionally, ART is used as post-exposure prophylaxis (PEP) to reduce the chances of HIV infection in healthcare workers following an accidental prick with an infected needle, and in other high-risk exposure situations.

Anti-HIV medications can interact with other drugs. Patients should inform their physician about all medications they are taking.

Sometimes HIV undergoes mutation while multiplying in the body and develops resistance to the medications.

When resistance develops, the treatment regimen may need to be changed to second-line or third-line drugs.

Prevention

AIDS is a preventable disease.

The following measures can help reduce the risk of HIV infection:

• Avoid unsafe sex: Use condoms every time you have vaginal, anal, or oral sex.
• Avoid multiple sexual partners: Avoid having more than one sexual partner as it increases the risk of acquiring HIV.
• Avoid sharing needles: Do not share needles, syringes, or other injection equipment.
• Get tested: Regular HIV testing is important, especially if you are at higher risk. Early detection allows for timely treatment.
• Ensure safe blood transfusion: Blood and blood products should be screened for HIV before transfusion.
• Prevention of mother-to-child transmission (PMTCT): Pregnant women should be tested for HIV. Antiretroviral treatment during pregnancy, delivery, and breastfeeding can significantly reduce the risk of transmission to the baby.
• Pre-exposure prophylaxis (PrEP): PrEP is a preventive medication for people at high risk of HIV exposure. When taken consistently, PrEP is highly effective in reducing the risk of acquiring HIV.
• Post-exposure prophylaxis (PEP): PEP involves taking antiretroviral medicines within 72 hours of possible exposure to HIV to prevent infection.

Frequently Asked Questions

1. What is the difference between HIV and AIDS?

HIV (human immunodeficiency virus) is the virus that attacks the immune system.

AIDS (acquired immunodeficiency syndrome) is the most advanced stage of HIV infection, diagnosed when the CD4 count falls below 200 cells/µL or when certain opportunistic illnesses develop.

Not everyone with HIV will develop AIDS, especially with timely treatment.

2. Can AIDS be cured?

There is currently no cure for HIV/AIDS.

However, antiretroviral therapy (ART) can effectively suppress the virus, allowing people living with HIV to lead long, healthy lives with near-normal life expectancy.

3. Is the procedure painful?

HIV testing involves a simple blood draw, which causes minimal discomfort.

ART medications are taken orally as tablets.

4. How long does the treatment take?

ART is a lifelong treatment.

With modern regimens such as DTG + TDF + 3TC, most patients take a single combined tablet once daily.

Regular follow-up visits are required to monitor viral load and CD4 counts.

5. What are the potential side effects of ART?

Modern ART regimens, particularly DTG-based regimens, are generally well tolerated.

Common side effects may include nausea, headache, fatigue, and sleep disturbances, which usually improve over time.

Older drugs such as Efavirenz and Zidovudine had more significant side effects, which is one reason for the global transition to DTG-based regimens.

Your doctor will monitor for any side effects and adjust treatment if necessary.

6. How many sessions are required?

ART is a continuous daily treatment, not a session-based therapy.

Follow-up appointments are scheduled regularly to monitor treatment progress, viral load, and CD4 counts.

7. What is the recovery time?

HIV is a chronic condition managed with lifelong ART.

Most people on effective ART achieve viral suppression within 3 to 6 months.

Immune recovery (improvement in CD4 counts) is gradual and continues over years of treatment.

8. Are there any age restrictions for HIV treatment?

There are no age restrictions for HIV treatment.

ART is available for children, adults, and older persons.

Paediatric formulations of ART, including DTG-based regimens, are available for infants and children.

9. Can I return to normal activities while on treatment?

Yes. With effective ART, most people living with HIV can continue their normal daily activities, work, exercise, and lead fulfilling lives.

With an undetectable viral load, people with HIV do not transmit the virus to sexual partners (U=U principle).

10. How do I find a doctor for HIV treatment?

Consult your primary care physician or contact Apollo Hospitals to find a specialist trained in HIV/AIDS management.

In India, free ART is also available through government ART centres under the National AIDS Control Programme.

Book an Appointment

If you or a loved one needs HIV/AIDS testing, treatment, or counselling, experienced specialists at Apollo Hospitals can help.

Early diagnosis and treatment are essential for better outcomes.

To book an appointment, visit apollohospitals.com/book-doctor-appointment or contact your nearest Apollo Hospitals centre.