HIV Transmission & Testing

Question 1

What is the most common mode of transmission of HIV?

Answer 1

Sexual transmission - approx. 40% between men and women and approx. 30% between men and women

Question 2

What are 4 factors that increase transmission risk of HIV?

Answer 2

Anoreceptive sex (trauma & lots of lymphoid tissue in anus), trauma, genital ulceration, concurrent STI

Question 3

What are 3 modes of parenteral transmission of HIV?

Answer 3

injection drug use, infected blood products, iatrogenic

Question 4

What are 3 modes of mother-to-child transmission of HIV?

Answer 4

in utero/trans-placental, delivery, breast-feeding

Question 5

Without intervention, 1 in 4 at risk babies will become infected with HIV and 1 in 3 HIV+ infants will die before first birthday if untreated. True/false?

Answer 5

True

Question 6

Where are there rising endemics? (2)

Answer 6

Russia & Eastern Europe

Question 7

Where are there HIV pandemics?

Answer 7

Sub-Saharan Africa, Caribbean, SEA (esp. Thailand)

Question 8

What is estimated percent of undiagnosed HIV cases in UK?

Answer 8

6%

Question 9

The following are prevalence ratios for HIV by risk groups. (PWID, heterosexuals and MSM). Ratios are 1:1000, 1:17 and 1:263. Match the correct risk group to the prevalence ratio.

Answer 9

1: 1000 - heterosexuals
1: 17 - MSM
1: 263 - PWID

Question 10

What makes you more likely to be diagnosed late in UK?

Answer 10

being a woman, aged >65 yrs, black african, heterosexual men, outside london

Question 11

Who should be tested for HIV according to UK guidance? (4)

Answer 11

Universal testing in high prevalence areas to all GP and medical admissions, opt-out HIV testing, screening of high risk groups, testing in presence of clinical indicators

Question 12

List 5 clinical settings in which opt-out HIV testing is carried out.

Answer 12

termination of pregnancy services, sexual health services, addiction and substance misuse services, antenatal services, assisted conception services

Question 13

List 7 groups considered high risk in UK as prevalence is higher than in the background population.

Answer 13

MSM, female partners of MSM, black africans, prisoners, trans women, PWID, partners of people living with HIV.

Question 14

List 4 groups from endemic areas that are considered high risk and should get screening for HIV.

Answer 14

adults from endemic area, children from endemic area, sexual partners from endemic areas, history of iatrogenic exposure in endemic area.

Question 15

If patient is incapacitated, you should only test if in patient’s best interest. Consent is required from relative to do HIV test. True/false?

Answer 15

False - you do not need to get consent from relative

Question 16

What markers of HIV are used by labs to detect infection and put them in order of detectable first to last?

Answer 16

Viral RNA (detectable first), p24 antigen (capsule protein) and antibodies

Question 17

After how many weeks will p24 show positive after infection?

Answer 17

6 weeks

Question 18

After how long will antibodies be detectable after infection with HIV?

Answer 18

3 months

Question 19

What does the following rapid HIV tests (POCT) indicate?

antigen negative, antibody positive

Answer 19

chronic infection

Question 20

What does the following rapid HIV tests (POCT) indicate?

antigen +ve, antibody -ve

Answer 20

early infection

Question 21

What does the following rapid HIV tests (POCT) indicate?

antigen +ve, antibody +ve

Answer 21

early infection

Question 22

What does the following rapid HIV tests (POCT) indicate?

antigen -ve, antibody -ve

Answer 22

can exclude HIV from 6 weeks previously - test is 99% sensitive at 45days