How HIV Affects the Body: Detailed Stages, Symptoms, and Long-Term Effects

Human Immunodeficiency Virus (HIV) is more than a viral infection; it is a chronic, progressive condition that impacts every system in the human body. Understanding HIV involves recognizing how it systematically weakens the immune system, how symptoms manifest at each stage, and the ways in which long-term infection alters physical and mental health. This article explores HIV’s specific effects on the body, dissecting each phase from acute infection to advanced disease, and detailing the biological mechanisms that drive symptoms and complications.

The Virus’s Target: CD4+ T Cells
HIV specifically attacks the immune system’s CD4+ T lymphocytes, crucial white blood cells responsible for organizing the immune response. The virus binds to CD4 receptors and co-receptors (CCR5 or CXCR4) on the surface of these cells, enters them, and uses their machinery to replicate.

Destruction of the Immune System
As HIV replicates inside CD4+ cells, it destroys them, leading to a gradual decline in immune function. This depletion of CD4+ T cells is central to HIV’s pathogenicity, eventually resulting in immunodeficiency and vulnerability to infections and certain cancers.

Acute HIV Infection (Primary Infection Stage)

Timeline and Viral Load
Acute infection occurs within 2–4 weeks of exposure. During this period, HIV replicates rapidly and the viral load in the bloodstream is extremely high, making transmission risk greatest.

Symptoms of Acute Infection

• Fever (most common, seen in over 80% of cases)
• Sore throat
• Swollen lymph nodes (especially in neck and armpits)
• Fatigue and malaise
• Rash (often non-itchy, red, and maculopapular, appearing on torso)
• Muscle and joint pain
• Headache
• Oral or genital ulcers

Mechanism of Symptoms
These symptoms, often called “acute retroviral syndrome,” arise as the immune system recognizes the viral invasion and mounts an aggressive, but non-specific, response. Because symptoms resemble those of other viral illnesses (like mononucleosis or flu), acute HIV is frequently missed or misdiagnosed.

Chronic HIV Infection (Clinical Latency Stage)

Silent Progression
After the acute phase, HIV enters a long “clinical latency” period, often lasting several years without obvious symptoms. The virus continues to replicate at low levels, but the immune system keeps pace by producing new CD4+ cells.

Subtle Symptoms
Most people feel healthy, but subtle signs may emerge over time:

• Persistent generalized lymphadenopathy (swollen lymph nodes in several areas)
• Mild fatigue
• Occasional minor infections (oral thrush, herpes zoster/shingles)

Immunological Changes
Despite feeling well, the ongoing battle between HIV and the immune system causes gradual immune exhaustion. CD4+ T cell counts slowly decline, and the ability to fight off less common pathogens is reduced.

Symptomatic HIV Infection

Progression to Overt Illness
As CD4+ counts fall below critical thresholds (usually under 500 cells/mm³), symptoms begin to manifest more clearly.

Common Symptoms and Opportunistic Infections

• Oral thrush (Candida infection in the mouth)
• Persistent diarrhea
• Severe weight loss (“HIV wasting syndrome”)
• Recurrent respiratory infections (pneumonia, tuberculosis)
• Herpes simplex outbreaks (chronic or severe)
• Shingles (herpes zoster, especially if occurring more than once)
• Night sweats
• Persistent fevers

Pathophysiology
These symptoms indicate immune suppression. Infections and cancers that would normally be controlled by the immune system begin to take hold.

Acquired Immunodeficiency Syndrome (AIDS)

Definition and Diagnostic Criteria
AIDS is diagnosed when the CD4+ cell count falls below 200 cells/mm³, or when certain defining opportunistic infections or cancers occur.

Opportunistic Infections and Cancers in AIDS

• Pneumocystis jirovecii pneumonia (PJP): Causes severe, progressive shortness of breath and cough
• Toxoplasma gondii encephalitis: Brain infection causing confusion, seizures
• Cytomegalovirus (CMV) retinitis: Can lead to blindness
• Tuberculosis: More aggressive and disseminated
• Kaposi’s sarcoma: Cancer causing purple skin lesions
• Non-Hodgkin lymphoma

Severe Systemic Effects
At this stage, HIV has essentially destroyed the immune surveillance system. Patients are vulnerable to infections and malignancies that rarely occur in people with healthy immune systems.

Immune System Exhaustion and Chronic Inflammation

Ongoing Immune Activation
Even with antiretroviral therapy (ART), HIV infection is associated with chronic immune activation. The immune system is constantly “on,” leading to gradual exhaustion and increased risk for non-AIDS complications.

Consequences of Immune Activation

• Accelerated aging (immunosenescence)
• Increased risk of cardiovascular disease
• Higher rates of certain cancers (even those not classically AIDS-defining)
• Bone loss (osteoporosis)
• Chronic kidney disease

Neurological and Cognitive Effects

HIV-Associated Neurocognitive Disorder (HAND)
HIV can cross the blood-brain barrier, infecting cells within the central nervous system (CNS). This can lead to cognitive decline, from mild forgetfulness to severe dementia (HIV-associated dementia).

Symptoms and Signs

• Memory loss
• Slowed thinking
• Impaired concentration
• Mood disorders (depression, anxiety)
• Movement disorders (tremors, poor coordination)

Gastrointestinal and Metabolic Complications

GI Manifestations
HIV commonly affects the gastrointestinal tract, leading to:

• Chronic diarrhea
• Malabsorption of nutrients
• Weight loss

Metabolic Syndrome
Chronic HIV infection and certain ART medications can result in metabolic disturbances, including:

• Lipodystrophy (abnormal fat distribution)
• Insulin resistance
• Hyperlipidemia (high cholesterol and triglycerides)
• Increased risk for type 2 diabetes

Effects on the Skin and Mucous Membranes

Cutaneous Manifestations
Skin issues are common throughout HIV infection:

• Seborrheic dermatitis (persistent dandruff or rash)
• Molluscum contagiosum (viral skin infection)
• Herpes simplex and zoster outbreaks
• Kaposi’s sarcoma lesions

Oral Complications

• Candidiasis (thrush)
• Oral hairy leukoplakia (white patches on the tongue)
• Ulcers and sores

Endocrine and Reproductive Effects

Hormonal Imbalances
HIV and its treatment can alter hormone levels, potentially causing:

• Menstrual irregularities in women
• Reduced testosterone in men (leading to fatigue, low libido)
• Infertility

Pregnancy and Mother-to-Child Transmission
HIV can cross the placenta or be transmitted during childbirth and breastfeeding if not properly managed with ART.

Cardiovascular and Renal Complications

Heart Disease
HIV increases the risk of atherosclerosis and heart attack, partly due to chronic inflammation and side effects of long-term ART.

Kidney Disease
HIV-associated nephropathy (HIVAN) is a unique form of kidney disease, most common in people of African descent, but HIV can also predispose to other renal issues.

Antiretroviral Therapy (ART)
Modern ART can suppress HIV to undetectable levels, halt CD4+ cell loss, and restore immune function in most patients. With adherence, people with HIV can live near-normal lifespans and avoid many complications.

Impact on Transmission
Undetectable = Untransmittable (U=U): If the viral load is undetectable, HIV cannot be sexually transmitted, which has revolutionized prevention and stigma reduction.

Residual Risks Despite Treatment
Even with ART, people with HIV face higher risks of:

• Cardiovascular disease
• Chronic inflammation-related illnesses
• Side effects from long-term medication use

Psychological Impact
A diagnosis of HIV can have profound emotional effects, including anxiety, depression, and stigma-related stress. Mental health care and strong social support are crucial.

Adherence and Monitoring
Staying healthy with HIV requires strict adherence to medication, regular monitoring of viral load and CD4+ counts, and proactive management of other health risks.

Support and Outlook
With early diagnosis and effective ART, most people with HIV lead full, productive lives. Prevention, education, and ongoing research continue to improve the long-term outlook.

Conclusion

HIV is a complex virus that affects the body in multiple, evolving ways. From the dramatic symptoms of acute infection to the slow, silent erosion of immune function and the myriad complications of advanced disease, HIV requires ongoing attention from both patients and healthcare providers. Modern treatments have transformed HIV from a fatal disease into a manageable chronic condition, but vigilance and comprehensive care remain essential to minimize its long-term impact.