AIDS epidemiology Flashcards by Gabor Szloboda

What are the global statistics for HIV and AIDS.

People living with HIV 39M.

New HIV infections 1.3M.

Deaths due to AIDS 630K.

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How many new HIV infections were diagnosed a day in 2022?

~3600 new ones.

1/2 in sub-Saharan Africa.
260 in children, 3200 in adults.

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What is the 90/90/90 goal set by UNAIDS?

global target of
-90% of people living with HIV being diagnosed
-90% diagnosed on ART (antiretroviral therapy)
-90% viral suppression for those on ART by 2020

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Fast-Track Cities

The Fast-Track Cities initiative
a global partnership
between a network of over 90 high HIV burden cities
where political leaders, affected communities, city health officials, clinical and service providers, and other stakeholders work together to accelerate their local HIV responses

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UK data between 2021 and 2022

New diagnoses increased in men&women
In women: 55% increase in new diagnoses between 2021 to 1,348 in 2022 and among men, an 8% increase
Of persons newly diagnosed in 2022, 72% were aged between 25 and 49 years
23% rise among those aged 25 to 34
24% rise among those aged 35 to 49
21% rise among those aged 50 to 64

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Did the UK achieve a 90-90-90 target?

Yes

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HIV transmission routes

Sexual
Vertical
Blood

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HIV prevention overview

Voluntary medical male circumcision
Treatment of STIs
Female condoms
Male condoms
HIV counselling and testing
Behavioural change
Treatment as Prevention (TasP)
PEP
PrEP
Microbicides for women and some gay men

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Partner notification and HIV

Discuss soon after diagnosis

The length of ‘look back’ depends on individual circumstances

Document discussion of safer sex practices, PEPSE, PreP for their partner (if applicable), U=U

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U=U

Undetectable = untransmittable

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PreP

Several RCTs on PreP; providing evidence for the effectiveness of daily dosing and event-based dosing
Effectiveness has been demonstrated in MSM (men who have sex with men), heterosexual serodifferent couples, trans, and injecting drug users

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PEP

Tablet after sex.

Post-exposure prophylaxis

PEP = 28 days Combination Antiretroviral Therapy –must be started within 72 hours after sex

Not to be confused with PreP

PEP is not as effective as PreP

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Benefits of knowing HIV status

Access to appropriate treatment and care
Reduction in morbidity and mortality
Reduction of vertical transmission
Reduction of sexual transmission
Public health / partner notification
Cost-effective

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Testing for HIV

Clinician initiated testing triggered by clinical indicators of immuno-suppression disease / seroconversion
Routine screening in high prevalence locations
Routine screening Antenatal screening
Screening in high risk groups
Patient initiated requests for testing

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Why do doctors not test for HIV?

They don’t think of HIV
Underestimate the risk of HIV in their patients
Failure to recognise HIV as a modifiable prognostic indicator
Misconception they need pre-test counselling
Misunderstanding of the implications for insurance, etc
Fear of offending the patient

…but these concerns have been overcome in the antenatal setting

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When to maintain a high index of suspicion?

Generalised lymphadenopathy
Acute generalised rash
Glandular fever/ flu-like illnesses
Think about seroconversion
Oral candida
Unexplained weight loss or night sweats
Persistent diarrhoea
Gradually increasing shortness of breath and dry cough
Recurrent bacterial infections including pneumococcal pneumonia

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Consider HIV if

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Flu-like illness, rash

Blood dyscrasias eg low platelets

Multi-dermatomal shingles

Lymphadenopathy

Weight loss or diarrhoea, night sweats, PUO

Oral/oesophageal candidiasis or hairy leukoplakia

How does testing occur in A&E departments?

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Routinely test (opt out testing).

Is pre-test HIV counselling required?

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Screening test

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Venous blood sample is preferred

4th generation HIV tests include p24 antigen and will detect the vast majority of infections at 4 weeks (if negative, repeat at 7 weeks if high index of suspicion)

High sensitivity and specificity

Point of Care tests

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Finger prick blood
Immediate result
Lower sensitivity and specificity
False positive and negative results
Longer incubation period

What are some of the advantages of POCT?

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Outreach into community settings/ non-specialist clinics
Increased patient choice
Increased access to testing and case detection
Earlier diagnosis in non-healthcare seeking individuals

Managing results

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Negative test
Repeat if within “window period”

Positive result or result not clear
Phone Sexual Health for advice and we’ll arrange an appointment within 48 hours
Explain test “reactive” and needs further investigation

Key populations to HIV prevention

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Sex workers and their clients, gay men and other MSM, people who inject drugs,
transgender people) - account for >70% new infections globally

We should also consider which populations?

Refugees (30.5m), asylum seekers (4.6m) and displaced people (53.2m)

Over 96% of new infections occur where?

LMICs

What are the socio-economic impacts of HIV in Africa?

Significant impact on life expectancy Loss of economically-productive adults (including health-care workers) Increased spending on healthcare (particularly as ART drug use becomes more widespread) Distortion of health-care spending Change in social structure: orphans cared for by elderly grandparents Stigma of HIV infection persists

Who are most at risk of acquiring HIV?

50% of all new infections occurring world-wide are in 15-24 year olds

Who is more likely to get HIV?

Women 2x

The risk of HIV transmission differs by biological sex

Male to female HIV transmission is 2-3x as efficient as female to male transmission Young women and teenagers are particularly vulnerable to HIV infection Risk is also increased during pregnancy and for 6 months post partum

What mechanisms make women more susceptible?

STIs causing inflammation/ulceration in the female genital tract Bacterial vaginosis can cause alterations in vaginal pH Hormonal effects on mucosal immunity Sexual violence

1 in 4 women infection occurs due to

Intimate partner violence

Paediatric HIV-1 infection in Africa occur via 3 routes...

In utero: transplacental, mostly during the third trimester Intra partum: exposure to maternal blood and genital secretions during delivery Breast milk: ingestion of large amounts of contaminated milk (45%) Transmission can largely be prevented by ART given to pregnant women and to the infant (MTCT) If maternal pVL is undetectable, risk of transmission is <2%

What is the first line treatment to prevent mother to child transmission?

Mother: First line antiretroviral therapy Breastfeeding infants: daily Nevirapine or AZT from birth until 4 to 6 weeks after cessation of breastfeeding

Early infant diagnosis

Most countries provide mass testing of infant dried blood spots before 6 weeks of age (using PCR).

Untreated HIV = particularly aggressive in African infants

Mortality of 35% - 54% Abundance of HIV target cells Infants have high lymphocyte counts ‘Immaturity’ of infant immune system May not make adequate immune response to HIV Genetic similarity of infant with donor of virus (i.e.mother) Likely to acquire HIV strains that have already “escaped” from maternal immune responses High incidence of co-infections Transmission of maternal infections Impact of maternal infection on placenta, e.g. malaria, CMV, EBV, TB More likely in low income countries

What are the barriers to adolescent testing?

difficulties in obtaining consent for HIV testing of older children in clinics Absent/ poorly defined/changing guardianship, Diagnosis leads to automatic disclosure of parental HIV status

What co-morbidities are seen in older children?

Heart muscle abnormalities Chronic lung disease Bronchiolitis obliterans Growth failure Osteoporosis is more likely

Prevention of HIV-1 transmission

Consistent condom use (80 – 90% effective) Male circumcision (60% reduction in infection – no benefit to female partners) Treating STIs (genital ulcers and HSV infection increase transmission risk) Microbicide gel for women (30 – 40% reduction in transmission risk) Needle and syringe exchange for IVDUs Post-exposure prophylaxis (PeP) Treatment as prevention (TasP) (96% reduction) Pre-exposure prophylaxis (PreP)

How does male circumcision prevent HIV?

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 (tissue DCs expressing CD4) which are prime targets for HIV. 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.

UNAIDS target for 2025

95-95-95

Examples of vaccine trials

AIDSVAX 2003 T-cell vaccines The Thai Vaccine trial (Rv144) Animal trials (CMV-vectored SIV)

AIDS epidemiology Flashcards

(42 cards)