HIV

1. National O.O. Bohomolet’s Medical
University
Department of Infectious Diseases
HIV infection:
basic concepts
Lecture for 5-th year students
National O.O. Bohomolet’s Medical
University
Department of Infectious Diseases

2. Lecture objectives
1. Be able to describe the uses for definitions:
“HIV infection”, “AIDS”, “ART”
2. Describe the distribution, transmission,
vulnerable groups for HIV infection
3. Explain the key points of path physiology of
HIV infection
4. Know the principles of prevention and
management of HIV infection

3. Definition
HIV-infection
– infectious disease caused by
human immunodeficiency virus (HIV), which
demonstrates high tropism to immune system
cells. Disease is characterized with long-lasting
latent course, and slow gradual progression from
asymptomatic carrying to firm irreversible
damages of immune system, which manifest with
severe life threatening infections, and tumors

4. Definition
Acquired immunodeficiency syndrome
(AIDs)
– final stage of HIV-infection, when
the progressive failure of the immune system
results to severe, fatal course of any infection;
disturbance of nerves system and all other
organs occurs, and without antiretroviral
therapy (ART) patient dies mostly from
opportunistic infections or malignancies.

5. GLOBAL HIV STATISTICS (UNAIDS, 2016)
 20.9 million people were accessing antiretroviral
therapy (ART) in June 2017
 76% of all pregnant women living with HIV
globally received ART in 2016
 36.7 million people were living with HIV
 1 mln people died from AIDS-related illnesses
 76.1 million people have become infected with
HIV since the start of the epidemic.
 35.0 million people have died from AIDS-related
illnesses since the start of the epidemic.

6. GLOBAL HIV STATISTICS (UNAIDS, 2016)
 1.8 million people
became newly infected
in 2016
 5000 new HIV
infections a day in 2016
 64% are in sub-Saharan
Africa
 400 are among children
under 15 years of age

8. Expectation vs. Reality

9. Etiology
 RNA-virus
 Family Retroviridae
 Subfamily Lentivirus
Proteins HIV-1 HIV-2
Envelope
glicoproteins
(env-gp)
gp120, gp160,
gp41
gp140, gp105
gp36
Group specific
antigen (gag-p)
p24, p17, p55 P26, p25, p56, p18
Polymerase (pol-p) p31, p51, p66 p68

10. HIV life cycle

11. Main targets for HIV
 CD4+ T lymphocytes
 monocytes/macrophages
 dendritic/Langerhans cells

13. Epidemiology
 Source of infection is any person with HIV-
infection. The risk of transmission was highest
during early-stage and advanced disease.
 HIV is contained in all biological fluids
 blood
 semen
 cervical secret
 Susceptibility is general. It depends on genetic
factors.

14. Epidemiology

15. Key populations and vulnerable groups
 men who have sex with men
 people in prisons and other closed settings
 people who inject drugs
 sex workers and
 transgender people.

16. Types of HIV testing
 HIV-1/2 antibody screening enzyme immunoassay
(EIA) – “3rd generation” or “ELISA”
 Rapid HIV tests (oral or blood)
 HIV Ab differentiation assay – “Western blot”
 HIV antigen & antibody combination immunoassay
– “4th generation”
 HIV RNA (PCR) –
“viral quantification”

17. ARV drugs
 NRTI Nucleoside/Nucleotide Reverse
Transcriptase (RT) Inhibitors
 NNRTI Non-nucleoside (RT) Inhibitors
 PI Protease Inhibitors
 EI Entry and Fusion Inhibitors
 INSTI Integrase Inhibitors
First-line regimens:
– 2 NRTI + [NNRTI, PI, or INSTI]

18. Principles of ART
1. ART should be initiated in all individuals soon
after assessment on HIV-status regardless of
WHO clinical stage or CD4 count (WHO, 2016)
2. ART is used in combination regimens and,
according to optimum schedules and dosages.
3. Life-long treatment
4. Monitoring of efficacy (viral load, CD4 count,
HIV resistance testing)
5. Monitoring of side effects

19. Prevention of sexual transmission
 Practice of
"safer sex”
 Latex condoms
are preferable
 Abstinence from
sexual relations

20. Prevention of HIV infection among IDUs
 Targeted information, education and communication
for IDUs and their sexual partners
 improve cultural and social standards of life
 to stop the use of injecting drugs
 the avoidance of sharing of needles, paraphernalia
should be cleaned after each usage with a virucidal
solution, such as undiluted sodium hypochlorite
(household bleach)
 IDUs should have access to sterile injecting
equipment through needle and syringe programmes
(NSPs)

21. Prevention of mother-to-child
transmission (MTCT)
1. Primary prevention of HIV infection among
women of childbearing age
2. Prevention of unintended pregnancies among
HIV-infected women
3. Preventing HIV transmission from women living
with HIV to their infants
4. Treatment, care, and
support to mothers
living with HIV, their
children and families.

22. Prevention of mother-to-child
transmission (MTCT)
 All pregnant and breastfeeding women living with
HIV should initiate triple ART, which should be
maintained at least for the duration of risk of
MTCT, but for programmatic and operational
reasons, particularly in generalized epidemics ART
should continue lifelong
 treatment postpartum ARVs for infant for the first
week following birth;
 PLCS at 38 weeks of pregnancy (not obligatory)
 avoidance of breastfeeding (or ART during
breastfeeding)

23. Post-exposure prophylaxis (PEP) for
HIV infection
 First aid care (us running water only)
 counseling and risk assessment
 HIV testing based on informed consent
 and depending on risk assessment, the provision
of short term (28 days) antiretroviral ARVs, with
follow up and support.

24. WHO PEP guidelines (2014)
 PEP should be initiated within hours of exposure
and not later than 72 hours after exposure and
should not be delayed while waiting for tests results.
 PEP should be administered for 28 days.
 PEP regimens, often composed by once daily triple
ARV drug combinations including nucleotide
analogues and heat stable boosted protease
inhibitors.
 More recently, other alternative drug classes such as
non-nucleside analogues and integrase inhibitors
have been considered.

25. Thank you for