Clinical aspects of HIV Flashcards
Name the government campaign out currently for HIV
Test more + treat early + stay safe = ending HIV
Approximately how many people in Australia are currently living with HIV?
27,000, approximately 1000 new cases a year.
~80% MSM
List the four types of biomedical prevention of HIV.
PrEP - pre-exposure prophylaxis
PEP - post-exposure prophylaxis - e.g. needle stick
TasP - treatment as prevention
MTCT mother to child transfer prevention
Name the drug used as biomedical prevention for HIV and state what two drugs it contains.
Truvada, has tenofovir and emtricitabine
Briefly describe HIV PrEP.
pre-exposure prophylaxis.
taken daily, combined with condoms and clean injecting kit.
Not on PBS for prevention, but legal for personal use.
Truvada cost ~$120.
Scenario: taken by negative partner while positive partner on initial treatment until viral load becomes undetectable.
Briefly describe HIV PEP.
Post-exposure prophylaxis.
Travada +/- 3rd antiviral, commenced preferably within 72 hours of exposure (best within 6 hours) and taken for 4 weeks after a possible exposure.
On PBS, no cost to the patient.
Briefly describe HIV TasP
Treatment as Provention.
when viral load below detection, 96% decrease in infections between serodiscordant heterosexual couples. Still recommend condoms.
Briefly describe HIV MTCT prevention.
prevention of mother to child transmission.
Mother: treatment with viral load below detection, normal if undetectable, further treatment and c-sect if detectable.
Infant: 4 weeks of PEP with zidovudine if mother’s viral load was undetectable, combination therapy if detectable.
What is the window period in HIV?
In Australia, the tests are able to detect most infections at 6 weeks, however window period may be up to 12 weeks depending on sensitivity. Protocol to retest at 3 months.
What are the screening tests for HIV?
2 different Ag/Ab detection tests.
HIV p24 antigen, a core antigen, detectable from 2-4 weeks but then declines after couple of months.
HIV antibody, detectable at 6 weeks.
What are the confirmatory tests for HIV?
repeat Ag/Ab
HIV1 western blot.
p24 antigen ELISA.
What tests are done to monitor treatment of HIV?
HIV viral load, assesses HIV RNA to quantify circulating virus and thus treatment response.
CT4 count.
HIV resistance testing - identifies mutations in the virus which are known to confer resistance to drugs for optimal treatment selection
Briefly describe the life cycle of HIV.
HIV contains ssRNA, reverse transcriptase, integrase and protease in a capsid with protein p24, surrounded by a membrane with gp120 and gp41.
HIV gp 120 + gp41 bind to CD4 on the surface of CD4 T cells, dendritic cells, macrophages, and monocytes, fuse with membrane and release viral genome into cytoplasm.
viral RNA is reverse transcribed into proviral DNA by reverse transcriptase.
proviral DNA is integrated into hose genome by integrase.
proviral DNA is transcribed into RNA
precursor proteins, cleaved by protease, produce mature proteins required with the RNA, assembly into virion, and budding and release of mature virion from cell.
How do the antivirals used to treat HIV work?
By inhibiting viral enzymes, such as reverse-transcriptase, integrase.
