HIV Basics and Infection Stages

HIV Basics

• HIV stands for Human Immunodeficiency Virus.
• AIDS stands for Acquired Immunodeficiency Syndrome.
• HIV attacks and destroys CD4 cells in the immune system.

HIV Transmission

• HIV spreads through specific bodily fluids from an infected person.
• These fluids include blood, semen, vaginal fluids, rectal fluids, and breast milk.
• In the US, the main transmission routes are sexual contact (homosexual or heterosexual), contact with infected blood (shared needles, occupational exposure) and mother-to-child transmission during pregnancy, childbirth, and breastfeeding.

HIV Infection Stages

• Infection is characterized by three stages:
  • Acute HIV Infection
  • Chronic HIV Infection
  • Acquired Immunodeficiency Syndrome (AIDS)

Acute HIV Infection

• Occurs 2-6 weeks after HIV infection.
• Symptoms may include fever, lymphadenopathy (swollen lymph nodes), pharyngitis (sore throat), and a diffuse maculopapular rash.
• HIV multiplies rapidly, spreading throughout the body and destroying CD4 cells.
• High levels of HIV in the blood greatly increase transmission risk.
• Antiretroviral therapy (ART) at this stage provides significant health benefits.

The Eclipse and Seroconversion Periods

• The eclipse phase is the period after HIV acquisition when tests cannot reliably detect HIV.
• This typically lasts around 10 days.
• The seroconversion window period is the interval between HIV acquisition and detection of HIV antibodies.
• The average window period is approximately 23-25 days.

HIV Testing

• Multiple methods exist for detecting HIV, including antigen-antibody tests, antibody tests (performed in labs or using point-of-care devices), and Western blot tests.

Testing After Exposure

• A negative HIV test 12 weeks after exposure is usually reliable for ruling out infection.

HIV-1/2 Antigen/Antibody Testing

• This assay detects both HIV-1 and HIV-2 antibodies and the p24 antigen.
• Different results of an HIV-1/2 Antigen/Antibody Immunoassay are possible
• (+): Negative for HIV-1 and HIV-2 antibodies and p24
• HIV-1/HIV-2 Antibody Differentiation Immunoassay can definitively identify the presence or absence of HIV-1 or HIV-2 antibodies

Chronic HIV Infection

• Acute infection subsides within weeks.
• Without treatment, progresses to chronic HIV infection.
• If the CD4 count falls below 200 cells/μL or the individual has an opportunistic infection, it is considered AIDS.

Who Should Be Tested?

• Initial/one time testing for individuals aged 15-65 who have no prior screening and are being treated for TB or other sexually transmitted diseases.
• Yearly testing for high-risk individuals (e.g., high-risk sexual behavior, IV drug users).
• Additional testing for factors like correctional facility entry, pregnancy, or occupational exposure to blood or body fluids.

Before Beginning ART

• Baseline CD4 count and viral load tests.
• Resistance testing (genotype testing) for all new patients starting ART.
• Baseline liver function tests (LFTs), chemistry, and lipid profiles for monitoring adverse drug reactions.
• Testing for co-infections (hepatitis A, B, and C).
• Tests for other conditions (e.g. Toxoplasma IgG, RPR, PPD/IGRA, HLA B5701).

Special Tests

• HLA-B*5701 screening before starting Abacavir to reduce the risk of hypersensitivity reactions.
• For HLA-B*5701 positive individuals, they should be recorded as allergic to Abacavir

When to Start ART?

• ART is recommended for all HIV-infected individuals, regardless of CD4 count, to reduce morbidity and mortality.
• ART is also recommended to prevent transmission.

FDA Approval of HIV Medicines

• A timeline of FDA approvals for various HIV medications.

What to Start for HIV Medications

• Integrase Strand Transfer Inhibitor regimens.
• Protease Inhibitor-Based Regimens.

Prophylaxis Against Opportunistic Infections

• Recommendations for prophylaxis based on CD4 count and opportunistic infections(e.g prophylaxis against PCP, toxoplasmosis and latent tuberculosis).

HIV Immunization

• Recommended vaccines for people with HIV (e.g., Hepatitis B, HPV, influenza, meningococcal, pneumococcal, monkeypox).

Pre-exposure Prophylaxis (PrEP)

• Approved for daily use by HIV-negative individuals to prevent HIV acquisition from positive partners.
• PrEP effectiveness depends on consistent use.
• New injectable HIV medications are available for PrEP.

Post-exposure Prophylaxis (PEP)

• Recommended for individuals within 72 hours of potential HIV exposure.
• PEP regimens should consist of three antiretroviral drugs.
• PEP treatment should continue for 28 days.
• Combo HIV 1/2 antigen-antibody immunoassay tests can confirm HIV status within 45 days of possible exposure

Review Questions and Answers

• (Note: Full question sets and answer explanations are given below)*
• Review questions address various scenarios about HIV infection, transmission, stages, diagnosis, treatment, and patient management to reinforce understanding.

This quiz covers the fundamentals of HIV, including its definition, transmission methods, and the stages of HIV infection. Test your knowledge on how HIV affects the immune system and learn about the symptoms associated with acute infection.