HIV and STIs Flashcards
HIV Transmission
Bodily fluids: blood, breast milk, semen, vaginal fluids
Blood: needle stick, contaminated surgical equipment
Sex = biggest mode of transmission
MTCT (Mother to child transmission)
Trends of HIV epidemiology
initially lots of people dying & lots of cases then peak 1990s/early 2000s then started to drop off due to effectiveness of treatment etc. (but on a graph number of people living with hiv going up (because people are living – not dying). Number of cases decreasing (partly because viral load is decreasing due to treatment so less infectious (U=U etc.))
Scale of HIV
(How many new cases, how many total, how many deaths)
worldwide
1.5 million new infections 2021
38.4 million people living with HIV 2021
650,000 AIDS related deaths 2021
Globally where are the most cases
Eastern & Southern Africa
Western & Central Africa
Southern Asia
Stages of HIV epidemic
Nascent: <5% Prevalence in all risk groups
Concentrated: >5% prevalence in one or more risk group
Generalised >5% prevalence in general population
What does who is most likely to be infected depend on
Where you are in the world and what stage the pandemic is in that area
E.g. in areas where epidemic is nascent or concentrated –> highest prevalence is in risk groups. Whereas in areas where HIV is endemic: more of the burden is in the heterosexual community
High risk groups for HIV
Sex workers
IVDU
Migrants from endemic countries
MSM
Clients of sex workers
Transgender women
Where do HIV cases come from UK (historically and now)
Initially cases were imported.
Now roughly 50% imported & 50% home grown
What percentages of cases are in high risk groups in Europe compared to E&S Africa
Europe: 99% infections in high risk groups
Eastern & Southern Africa: 25% in high risk groups - most cases in general population
What stage of the HIV Epidemic is the UK in
Concentrated phase
What is the UK prevalence of HIV
(& rough african)
UK: 0.2%
Some African Countries: 20%
Goals of HIV testing services
- Provide a high quality service for identifying HIV
- HIV treatment
- HIV Care
- HIV Support
- Prevent Transmission (PMTCT - prevention of mother to child transmission; VMMC - voluntary medical male circumcision; PrEP; PEP
Aim to close the gap and get people on ART asap
Need to identify high risk groups e.g. TB patients
5 Cs of WHO HIV Testing Services
Consent (for testing, treatment etc. - don’t force people)
Confidentiality
Counselling (psychological trauma, often get diagnosed with multiple diseases at once e.g. TB & HIV)
Correct test results
Connection /linkage to prevention, care & treatment - no point testing if not going to treat
What is the new focus to address the HIV testing gap
Emphasis on quality, efficiency, yield & linkage
o Improving quality to prevent misdiagnosis
o Getting testing out into communities
o Supporting better linkage
o Better focus and appropriate targeting.
Common reasons for HIV misdiagnosis
Clerical/technical errors (mislabelling, poor records etc.)
User error (of tests)
Cross reactivity (antibodies from intercurrent infection, late stage AIDS etc.)
Incorrect/suboptimal testing strategy
Poor management & supervision
How to test for HIV
combination of rapid diagnostic tests (RDTs) and/or enzyme immunoassays which, when used together, achieve at least a 99% positive predictive value.
How many HIV tests to do in lower burden countries
Lower burden = <5% prevalence
3 consecutive reactive tests
How many HIV tests to do in high burden countries
High burden = >5% prevalence
2 consecutive reactive tests
How to get testing out into communities
Rapid diagnostic tests (finger prick)
Lay testers & task shifting
Self testing
Home, mobile & outreach testing (moonlight testing, schools, workplaces, religious facilities etc.)
Rapid tests in shopping centres etc.
Occupational health
Screening for pregnant women
HIV Testing: linkage to care and prevention
Don’t just test: if positive counselling & linkage to treatment
If negative: link to prevention services - condoms etc.
Who are the key populations to target for HIV testing
o Pregnant women
o Couples & partners
o Men
o Infants, children, adolescents
o TB
o Sex workers
o IVDU
o MSM
o Transgender people
How else to target key populations HIV testing
HIV partner services: couples/contacts testing & counselling
Facility based HIV testing services – entry via HIV and ART services – test for TB. And entry via TB services – test for HIV etc.
(&STI, Hepatitis, Antenatal)
How to address HIV (generally)
Regular STI testing (STIs all augment each other)
Education - condoms, awareness etc.
PrEP & PEP
Address stigma
Outreach programmes for risk groups
Should a HIV positive mother breast feed
Risk of transmission from mother to child while breast feeding.
But in many LMICs the risks of not breast feeding are really high: malnutrition, immune system etc.
Best practice: treat mother with ARTs so U=U and baby safe for breastfeeding
Can HIV be transmitted on saliva
No/very low.
Don’t need to worry about contaminated utensils etc.
Strategies for preventing HIV transmission
- PrEP
- Blood supply screening
- Condoms
- Education/behaviour modification
- Clean syringes
- Treatment/prevention of drug/alcohol abuse
- Microbicides
- STI treatment
- Medical male circumcision
- Treatment as prevention
- HIV testing/counselling
- PMTCT
Most effective –> least effective HIV prevention strategies
ART
PrEP
VMMC
STI treatment
Microbicide
HIV vaccine
Issues with condoms
Only work if used properly - before any sexual contact
Need to challenge cultural norms: “doesn’t feel as good with a condom etc.” (and can be difficult to get condoms)
Other risk factors for HIV
Sexual violence
Why does circumcision work
*By removing foreskin, circumcision reduces the ability of HIV to penetrate due to keratinization of the inner aspect of the remaining foreskin.
* The inner part of the foreskin contains many Langherhans cells, that are prime targets for HIV. Some of these are removed with the foreskin.
* Ulcers, characteristic of some STI’s that can facilitate HIV transmission, often occur on the foreskin. By removing the foreskin, the likelihood of acquiring these infections is reduced.
* The foreskin may suffer abrasions or inflammation during sex that could facilitate the passage of HIV.
How to prevent HIV transmission through IVDU/syringes
Needle & syringe programmes
Drug dependency treatment - in particular opioid substitution therapy
Close compulsory drug detention & rehab centres
Management of TB & viral hep
Clean syringes
Discourage needle sharing
How to reduce MTCT of HIV
Comprehensive antenatal HIV screening & appropriate ART
HIV retesting during 3rd trimester
Encourage breastfeeding