HIV is a retrovirus that infects cells of the immune system.
It destroys or impairs the function of these cells, weakening the immune system.
As the infection progresses, the person becomes more susceptible to infections.
Anatomy of the AIDS Virus
gp120: Envelope protein.
gp41: Envelope protein.
RNA: Genetic material of the virus.
p17: Matrix proteins.
Lipid Membrane: Outer layer of the virus.
p24: Capsule proteins.
Reverse Transcriptase: Enzyme used for replication.
How HIV Weakens the Immune System
HIV targets the immune system, weakening the body's defense against infections and some cancers.
The virus destroys and impairs immune cells, leading to immunodeficiency.
Immune function is measured by CD4 cell count.
AIDS (Acquired Immunodeficiency Syndrome)
AIDS is the most advanced stage of HIV infection.
It can take 2 to 15 years to develop, depending on the individual.
Antiretroviral drugs can slow down the progression to AIDS.
AIDS has severe clinical manifestations.
Signs and Symptoms of HIV
Symptoms vary depending on the stage of infection.
Individuals are most infectious in the first few months but may be unaware of their status.
Initial infection may present with no symptoms or an influenza-like illness (fever, headache, rash, sore throat).
As the immune system weakens, other symptoms can develop: swollen lymph nodes, weight loss, fever, diarrhea, and cough.
Without treatment, severe illnesses such as tuberculosis, cryptococcal meningitis, and cancers can occur.
HIV Transmission
HIV is transmitted through the exchange of body fluids: blood, breast milk, semen, and vaginal secretions.
It is NOT transmitted through ordinary day-to-day contact (hugging, shaking hands, sharing personal objects, food, or water).
Specific modes of transmission:
Unprotected sexual intercourse.
Transfusion of contaminated blood.
Sharing contaminated needles.
Mother to infant during pregnancy, childbirth, and breastfeeding.
Risk Factors for HIV
Having unprotected sex.
Having another sexually transmitted infection (syphilis, herpes, chlamydia, gonorrhea, bacterial vaginosis).
Sharing contaminated needles, syringes, and other injecting equipment.
Receiving unsafe injections, blood transfusions, or medical procedures involving unsterile cutting or piercing.
Experiencing accidental needle stick injuries (including among health workers).
Global HIV/AIDS Statistics (2022)
85.6 million people have become infected with HIV since the start of the epidemic.
40.4 million people have died from AIDS-related illnesses since the start of the epidemic.
39.0 million people globally were living with HIV.
37.5 million adults (15 years or older).
1.5 million children (0–14 years).
53% of all people living with HIV were women and girls.
1.3 million people became newly infected with HIV.
630,000 people died from AIDS-related illnesses.
AIDS-related mortality has declined by 55% among women and girls and by 47% among men and boys since 2010.
29.8 million people were accessing antiretroviral therapy.
The Sustainable Development Goals (SDGs)
Adopted in 2015 to end the AIDS epidemic by 2030 under SDG Goal 3: “ensure healthy lives and promote well-being for all at all ages.”
Successor to the Millennium Development Goals (MDGs).
MDG 6 included an HIV target: to halt and begin to reverse the spread of HIV/AIDS by 2015 and to achieve universal access to treatment for HIV/AIDS by 2010.
95-95-95 Targets by 2025 (UNAIDS)
Ambitious targets released in 2020:
First 95%: 95% of people living with HIV knowing their HIV status.
In 2022, 86% knew their status.
Second 95%: 95% of people who know their HIV-positive status are on treatment.
In 2022, approximately 89% were accessing treatment.
Third 95%: 95% of people on treatment with suppressed viral loads.
In 2022, 93% were virally suppressed.
Diagnosis of HIV
Serological tests (Rapid diagnostic tests - RDTs or enzyme immunoassays - EIAs) detect the presence or absence of antibodies to HIV antigen.
These tests detect antibodies produced by the individual's immune system, not the virus itself.
Antibodies may not be detectable early after infection (the window period), typically within 28 days.
This early period is the time of greatest infectivity; however, HIV transmission can occur during all stages of infection.
HIV Testing Services
HIV testing should be voluntary, and the right to decline testing should be recognized.
Mandatory or coerced testing is unacceptable as it undermines public health and infringes on human rights.
All HIV testing services must include the 5 C’s recommended by WHO: informed Consent, Confidentiality, Counselling, Correct test results, and Connection (linkage to care, treatment, and other services).
Self-Testing for HIV
HIV self-testing involves a person collecting a specimen, performing a test, and interpreting the results in private.
It is an initial test that requires further testing by a health worker; it does not provide a definitive diagnosis.
HIV Prevention
Male and female condom use
Testing and counseling for HIV, TB, and STDs
HIV testing services should integrate screening for TB and STDs.
Individuals diagnosed with HIV who have active TB should urgently use ART.
Voluntary medical male circumcision
Pre-exposure prophylaxis (PrEP) for HIV
Post-exposure prophylaxis for HIV (PEP)
Elimination of mother-to-child transmission of HIV (EMTCT)
Harm reduction for injecting drug users
Using sterile syringes
HIV testing and counseling
HIV treatment and care
Access to condoms
Management of STIs, tuberculosis, and viral hepatitis.