PHM203 Lecture 22: HIV - Questions With Correct
Solutions
Who is most likely to get HIV? Right Ans - People facing multiple barriers
(e.g. indigenous gay men)
Racism, economic exclusion, stigma and criminalization also negatively affect
care and treatment outcomes
Race/ethnicity data is not reported consistently
What is HIV? Right Ans - human immunodeficiency virus
having HIV does not mean a person has AIDS
Thought to have progressed from SIV (simian immunodeficiency virus)
What is AIDS? Right Ans - acquired immune deficiency syndrome
Untreated HIV will progress to AIDS
HIV-1 vs HIV-2 Right Ans - HIV-1 is the predominant cause of AIDS
Has 4 groups, with many subtypes
(M group has 9 subtypes)
Cabotegravir less effective in subtypes A1/A6
HIV-2 is less virulent, transmissible, and prevalent than HIV-1
found in west africa
How is HIV transmitted? Right Ans - Mainly Through Blood & Unprotected
Sex
- e.g. transfusions, sharing needles
-can be transmitted vertically (mother to fetus)
What are the risk factors for HIV? Right Ans - Rectal intercourse (is
traumatic: rupture of mucous membranes)
Heterosexual Intercourse*
Perinatal*
Sharing contaminated needles
*more common risk factors in poorer countries
What are the methods with the highest transmission rates? Right Ans -
Blood Transfusion
Receptive Anal Intercourse
, Needle-sharing
Needle stick injury
Insertive anal intercourse
Receptive vaginal
Insertive vaginal
How do we diagnose HIV? Right Ans - **Need to make sure it has been 5
days since exposure (Eclipse Period)
Days 6-8 NAAT
Days 13-20 p24 viral antigen detectable
Day 20 IgM antibodies detectable
Day 30 IgG antibodies detectable
NAAT HIV POC testing Right Ans - >99% sensitive and specific
(unless in eclipse period)
Needs to be confirmed with antigen/antibody testing for diagnosis
Monitoring of HIV Right Ans - Viral load (RNA copies/mL)
Target: Undetectable (typically <50 copies/mL)
Undetectable = Untransmissible
"Speed of Car"
CD4 Cell count
Target: As high as possible!
(>200 cells/mm^3 to avoid OIs)
Normal is 500-1600
"length of road"
What is the clinical presentation of HIV? Right Ans - Typically "flu-like"
symptoms lasting ~2 weeks
Resembles mononucleosis illness
(happens due to seroconversion of virus)
People often say it was one of the sickest they have been
Attachment Right Ans - HIV protein gp160 is made up of gp120 & gp41
subunits
gp120 binds to CD4 Receptor, but requires a co-receptor for attachment to the
CD4 cells
2 chemokine co-receptors on CD4 cells:
Solutions
Who is most likely to get HIV? Right Ans - People facing multiple barriers
(e.g. indigenous gay men)
Racism, economic exclusion, stigma and criminalization also negatively affect
care and treatment outcomes
Race/ethnicity data is not reported consistently
What is HIV? Right Ans - human immunodeficiency virus
having HIV does not mean a person has AIDS
Thought to have progressed from SIV (simian immunodeficiency virus)
What is AIDS? Right Ans - acquired immune deficiency syndrome
Untreated HIV will progress to AIDS
HIV-1 vs HIV-2 Right Ans - HIV-1 is the predominant cause of AIDS
Has 4 groups, with many subtypes
(M group has 9 subtypes)
Cabotegravir less effective in subtypes A1/A6
HIV-2 is less virulent, transmissible, and prevalent than HIV-1
found in west africa
How is HIV transmitted? Right Ans - Mainly Through Blood & Unprotected
Sex
- e.g. transfusions, sharing needles
-can be transmitted vertically (mother to fetus)
What are the risk factors for HIV? Right Ans - Rectal intercourse (is
traumatic: rupture of mucous membranes)
Heterosexual Intercourse*
Perinatal*
Sharing contaminated needles
*more common risk factors in poorer countries
What are the methods with the highest transmission rates? Right Ans -
Blood Transfusion
Receptive Anal Intercourse
, Needle-sharing
Needle stick injury
Insertive anal intercourse
Receptive vaginal
Insertive vaginal
How do we diagnose HIV? Right Ans - **Need to make sure it has been 5
days since exposure (Eclipse Period)
Days 6-8 NAAT
Days 13-20 p24 viral antigen detectable
Day 20 IgM antibodies detectable
Day 30 IgG antibodies detectable
NAAT HIV POC testing Right Ans - >99% sensitive and specific
(unless in eclipse period)
Needs to be confirmed with antigen/antibody testing for diagnosis
Monitoring of HIV Right Ans - Viral load (RNA copies/mL)
Target: Undetectable (typically <50 copies/mL)
Undetectable = Untransmissible
"Speed of Car"
CD4 Cell count
Target: As high as possible!
(>200 cells/mm^3 to avoid OIs)
Normal is 500-1600
"length of road"
What is the clinical presentation of HIV? Right Ans - Typically "flu-like"
symptoms lasting ~2 weeks
Resembles mononucleosis illness
(happens due to seroconversion of virus)
People often say it was one of the sickest they have been
Attachment Right Ans - HIV protein gp160 is made up of gp120 & gp41
subunits
gp120 binds to CD4 Receptor, but requires a co-receptor for attachment to the
CD4 cells
2 chemokine co-receptors on CD4 cells:
