ID - HIV

Question 1

What type of virus is HIV?

Answer 1

RNA retrovirus

Question 2

What are the types of HIV?

Answer 2

HIV-1 (most common)
HIV-2 (mainly found in West Africa)

Question 3

Outline retroviral replication

Answer 3

• Virus binds to a CD4+ on cell surface & fuses with cell
• Virus penetrates & empties into cell
• Viral ssRNA → dsDNA by reverse transcriptase
• Viral DNA integrated into host DNA by integrase
• Viral DNA transcripted during infected cell division
• Viral protein chains assemble & bud out of cell and matures as protein chains are cut by protease

Question 4

Why does a flu-like illness occur in the first few weeks of infection?

Answer 4

Initial seroconversion

Question 5

How is HIV transmitted?

Answer 5

• Unprotected anal, vaginal or oral sex
• Vertical transmission
• Mucous membrane, blood or open wound exposure to infected blood or bodily fluid (needles or blood splash in eye)

Question 6

How is mode of delivery determined in HIV positive mothers?

Answer 6

Mother’s viral load

Question 7

What modes of delivery are used for different viral loads?

Answer 7

IV Zidovudine during labour and delivery if viral load is unknown or above 1000 copies/ml

Prophylaxis given to baby
- Low-risk babies (under 50 copies) given zidovudine for 2-4 weeks
- High-risk babies (over 50 copies) zidovudine, lamivudine and nevirapine for 4 weeks

Question 8

Can mothers with HIV breastfeed?

Answer 8

No

Can be transmitted during breastfeeding even if low risk

Sometimes mother can be adamant and can be attempted with close monitoring by HIV team

Question 9

What might a positive result for HIV in a new-born be due to?

Answer 9

Maternal antibodies in children under 18 months

Does not necesarily mean HIV positive

Results should be discussed with ID specialists

Question 10

What are the two options for testing in HIV?

Answer 10

HIV antibody screen
- Tests whether immune system has created antibodies due to HIV exposure
- Can give false positive in babies with HIV positive mum, due to maternal antibodies crossing placenta, can take up to 3 months for antibodies to develop after

HIV viral load
- Tests directly viral count in blood
- Never falsy positive
- Can be undetectable if patients on antiretrovirals

Question 11

When is HIV tested for?

Answer 11

• HIV positive parents
• Suspected immunodeficiency, unusual, severe or frequent infections
• Young people who are sexually active, can be offered testing if there are concerns
• Risk factors e.g. needle stick injuries, sexual abuse or IVDU

Question 12

How many times are babies with HIV positive parents tested for HIV?

Answer 12

Twice

HIV viral load at 3 months
If negative child has not contracted HIV during birth, will not develop unless further exposure

HIV antibody test at 24 months
See if contracacted via breast feeding, should be negative if no breastfeeding and 3 month is negative

Can be positive in infants who do not have HIV up to 18 months due to maternal antibodies crossing placenta

Question 13

How is HIV treated?

Answer 13

Coordinated by paediatric HIV specialists
- Antiretroviral therapy
- Normal childhood vaccinations, avoid or delay live vaccines if severely immunosuppressed
- Prophylactic co-trimoxazole (septrin) for kids with low CD4, protect against PCP
- Treat opportunistic infections

Question 14

What is the aim of antiretroviral therapy?

Answer 14

Normal CD4 count
Undetectable viral load

Question 15

What should a paediatric HIV MDT do?

Answer 15

• Regular growth and development follow-ups
• Dietician input for nutritional support
• Parental education
• Delayed diagnosis to child until mature enough
• Psychological support
• Specific sex education in relation to HIV