1. HIV 101 Dr Sindisiwe van Zyl sindi@drsindi.co.za
Saturday 25 August 2018
Pretoria

2. Introduction

3. MAP OF THE WORLD
© Copyright SASI Group (University of Sheffield) and Mark Newman (University of Michigan).

4. Worldwide HIV prevalence in adults aged 15 – 49 © Copyright SASI Group (University of Sheffield) and Mark Newman (University of Michigan).
Map from worldwide mapper showing country size according to HIV prevalence

5. WHAT IS HIV? retrovirus and a lentivirus – slow progress
The HUMAN IMMUNODEFICIENCY VIRUS (HIV)
retrovirus and a lentivirus – slow progress
uses the body’s own cells to make copies of itself
attacks the body’s immune system
causes AIDS – Acquired Immune Deficiency Syndrome

6. BACK TO BASICS CD4 cells – most important cells in the body “army”
HIV – targets CD4 cells, hijacks them and starts making copies of itself
VIRAL LOAD – the number of HIV copies in your body
ART antiretroviral therapy – combination of 3 or more ARVs taken to suppress the virus’ ability to make copies of itself

7. What else do we know about HIV?
2 types of HIV
HIV - 1 – global distribution, mutates easily
many subtypes of HIV - 1: A - K
southern Africa subtype C dominates
HIV - 2 – isolated to West Africa
slower disease progression
5 subtypes

8. TRANSMISSION OF HIV
unprotected sexual intercourse with an infected person
from mother to child – pregnancy, labour and delivery, breastfeeding
occupational exposure
infected blood products

9. NOT transmitted by… Casual contact – handshakes Hugging
Sharing cups and utensils
Coughing or sneezing
Crying
Sweating
Kissing

10. Risk factors for transmission
Biological risk factors
presence of STIs
women more vulnerable physiologically
semen is deposited into vagina, stays there for days
whilst males “dip in & dip out”
area of mucous membrane exposed during sex much larger
viral load in source partner
(genetics – co-receptor deletion; < 1% of population)
Not all penetrative sexual contact with an infected partner leads to infection
SERODISCORDANT COUPLES

11. Structure of HIV

12. Target cells of HIV “ the enemy”
HIV targets specific cells of the immune system “army”
cells with CD4 receptors
happen to be VERY important members of the defence force

13. Life cycle of HIV Binding+ fusion Releases contents Makes RNA into DNA
Inserts its own DNA into human DNA
Takes over the cell and makes new viruses

14. many millions of viruses are made daily – viral load
CD4 cells are destroyed in the process
immune system can no longer function normally; inflammatory process

15. 4 Stages of HIV infection
Primary and acute HIV infection
‘window period’
followed by seroconversion: production of antibodies
asymptomatic phase
symptomatic disease
AIDS

16. Primary and acute HIV infection
initially asymptomatic
then 6 – 12 weeks after infection
non-specific viral symptoms
HIGH viral load
a drop in CD4 count
“window period”
seroconversion

17. Asymptomatic phase no symptoms for years but do not be fooled
the war is raging on…
CD4 cells putting up a fight
but immune system is suffering

18. Symptomatic phase immune system ‘tired’ mild symptoms initially
but gradually worsen
opportunistic infections

19. AIDS immune system can no longer function normally
without ART death follows

20. Anti-retroviral Therapy ART
Reverse transcriptase
inhibitors X
Fusion
inhibitors X X
Integrase
inhibitors X
Protease
inhibitors
Maturation
inhibitors X

21. Treatment works!

22. Three-in-one combination

23. New kid on the block

24. HIV affects eveybody Nobody is immune – NO assumptions!
(Almost) everyone is sexually active
Test BEFORE embarking on a sexual relationship
Keep testing – every 6 – 12 months

25. Know your HIV status Every individual must know their status
Cannot rely on your partner to test on your behalf “proxy testing”
It is better to know earlier rather than later

26. Condoms work If used correctly and consistently
Intermittent use is the same as no use
Male condom and female condom
Non-latex condoms are available - expensive

27. PEP Post Exposure Prophylaxis

28. PEP Post Exposure Prophylaxis
Pre-condition: YOU must be HIV negative
Must be taken within 72 hours of exposure
Must be taken for 28 days
Repeat HIV test after the course and after 12 weeks

29. PrEP Pre Exposure Prophylaxis

30. PrEP Pre Exposure Prophylaxis
Part of “Combination Prevention” strategy
Trials have proven efficacy: >90% effective
Commit to three – four monthly check-ups
Lead-in time: tablet must be taken DAILY
7 days with recipient anal sex
20 days with vaginal sex

31. Undetectable equals Untransmittable

32. Resources