What is HIV?

HIV stands for human immunodeficiency virus.  Infection by this virus frequently leads to AIDS – acquired immunodeficiency syndrome. Viral infection initially causes a flu-like illness characterized by fever, sore throat, headache, rash, gastrointestinal discomfort, and body aches (myalgia).  The virus tends to stay dormant for months or years while it is slowly killing immune cells – especially CD4 cells.

Individuals with high viral loads and low CD4 cell counts have high viral infectivity and tend to develop opportunistic infections – atypical infections that generally affect immunocompromised hosts.  AIDS is a common cause of death worldwide, buts its medical treatment in developed countries has led to a significant reduction in mortality and complications.  Despite this, many underserved countries still suffer grave consequences from this serious viral illness.

What Causes HIV Infection?

HIV is caused by the human immunodeficiency virus.  People typically acquire HIV infection through sexual, oral, or anal intercourse due to exchange of bodily fluids.  Patients may also develop infection through the blood by either abusing drugs and sharing needles with other infected persons or rarely via blood transfusion (donor blood is contaminated with virus).

This virus enters the blood stream and infects CD4 cells – a form of white blood cell - eventually leading to cellular death. These cells are important for proper function of the immune system.  Primary viral infection generally produces flu-like symptoms - however, unlike the flu, HIV goes on to suppress the immune system, resulting in constitutional symptoms (e.g., weight loss, night sweats), and opportunistic infections.  In fact, HIV infection is a leading cause of immunosuppression worldwide and in the United States.

The virus tends to lie dormant for months or years, slowly and progressively killing immune cells.  Patients eventually develop opportunistic infections as their CD4 counts decrease below 200.

How Common is HIV Infection?

HIV is relatively common in the United States and responsible for a fair amount of deaths.  This condition is a frequent cause for referral to an infectious disease specialist.

In 2015, worldwide - approximately 37 million adults and children had HIV or AIDS, 2 million were newly infected that year, and 1 million people died of the condition.  Sub-Saharan Africa makes up about 75% of the word’s HIV-infected population.  Approximately 3.3 million children have HIV/AIDS in the world – most of these patients are born in sub-Saharan Africa and Southeast Asia.

The prevalence of HIV seems to be stabilizing overall, however some countries are still demonstrating an increase.  Since 2001, there has been about a 38% decrease in the incidence of HIV infection.

Signs and Symptoms

Symptoms of acute HIV infection are flu-like and typically include:

  • Fever
  • Enlarged and painful lymph nodes - lymphadenopathy
  • Rash
  • Sore throat
  • Body aches
  • Headache
  • Weight loss
  • Night sweats
  • Anorexia - loss of appetite

These typically subside and the virus then hibernates in the lymphatic system.  Months or years later, the CD4 cells become significantly depleted and patients develop an AIDS defining lesion or opportunistic infection.  Opportunistic illnesses generally happen when the CD4 count is <200.  The most common AIDS defining illnesses include Pneumocystic jiroveci pneumonia, esophageal candidiasis, Kaposi sarcoma, wasting syndrome, and disseminated Mycobacterium avium infection.


The diagnosis of HIV is suggested based on symptoms and physical examination, but typically confirmed with laboratory studies.  Your doctor will typically check you for HIV viral load, HIV PCR and antibodies, as well as CD4 counts.  They will also typically test for HIV resistance patterns to guide treatment.

Other commonly ordered blood tests include a CMP (comprehensive metabolic panel), CBC (complete blood cell count), and thyroid function (TSH, free T4).  They will also usually check your cholesterol levels and screen for diabetes.  Urine tests typically include a urinalysis and gonorrhea/chlamydia PCR.

Additional blood tests for sexually transmitted infections include hepatitis B and C serology, and RPR for syphilis.  Your doctor will also usually order a TB test and or obtain a chest x-ray to evaluate your lung anatomy.

HIV Medication and Treatment

HIV is treated with antiretroviral therapy (ART).  This typically includes nucleoside reverse transcriptase inhibitors, nonnucleoside reverse transcriptase inhibitors, and protease inhibitors.

Nucleoside reverse transcriptase inhibitors are available as:

Non-nucleoside reverse transcriptase inhibitors are usually given with nucleoside reverse transcriptase inhibitors.  Common options include:

Commonly prescribed protease inhibitors include:

Integrase inhibitors such as Isentress (raltegravir) may also be recommended.

Treatment is generally continued life-long.


  1. Daar ES, Little S, Pitt J, et al. Diagnosis of primary HIV-1 infection. Los Angeles County Primary HIV Infection Recruitment Network. Ann Intern Med 2001; 134:25. -
  2. Braun DL, Kouyos RD, Balmer B, et al. Frequency and Spectrum of Unexpected Clinical Manifestations of Primary HIV-1 Infection. Clin Infect Dis 2015; 61:1013. -
  3. Patel P, Mackellar D, Simmons P, et al. Detecting acute human immunodeficiency virus infection using 3 different screening immunoassays and nucleic acid amplification testing for human immunodeficiency virus RNA, 2006-2008. Arch Intern Med 2010; 170:66. -
  4. Lodi S, Phillips A, Touloumi G, et al. Time from human immunodeficiency virus seroconversion to reaching CD4+ cell count thresholds <200, <350, and <500 Cells/mm³: assessment of need following changes in treatment guidelines. Clin Infect Dis 2011; 53:817. -

The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.