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Session 14 Oral Abstracts
Prevention of Mother-to-Child Transmission
Session Day and Time: Monday, 4-6 pm
Presentation Time: 4:45 pm
Room: Room 302-304


45aLB
Prevention of Mother-to-Child Transmission of HIV-1 among Breastfeeding Mothers Using HAART: The Kisumu Breastfeeding Study, Kisumu, Kenya, 2003–2007
Timothy Thomas*1, R Masaba2, R Ndivo2, C Zeh1, C Borkowf3, M Thigpen3, K De Cock4, P Amornkul4, A Greenberg3, M Fowler3, and Kisumu Breastfeeding Study Team
1CDC Kenya, Kisumu; 2Kenya Med Res Inst, Kisumu; 3CDC, Atlanta, GA, US; and 4CDC Kenya, Kisumu

Background:  Several trials are underway to assess use of extended maternal or infant antiretrovirals (ARV) to reduce mother-to-child transmission (MTCT) among HIV-exposed breastfed infants where infection rates of 25 to 48% have been observed. We assessed transmission rates in the Kisumu Breastfeeding Study (KiBS), a phase IIb single-arm prevention of (PMTCT) trial using zidovudine/lamivudine and nevirapine (NVP) (later modified to nelfinavir [NLF] for those women with CD4 >250 cells/µL) from 34 weeks’ gestation to 6 months’ postpartum. Infants received single-dose NVP at birth. Women were advised to exclusively breastfeed and wean rapidly at 6 months.

Methods:  We tested infant dried blood spots collected at delivery, 2, 6, and 14 weeks and 6, 9, and 12 months using polymerase chain reaction (PCR). Kaplan-Meier methods were used to estimate rates of HIV infection overall, by maternal enrolment CD4 count (≤ or >250 cells/µL) and by initial regimen (NVP or NLF) for those with maternal CD4 >250 cells/µl.

Results:  HIV infection data were available for 497 infants born alive:  27 (11 males, 16 females) became infected, 3 after 6 months. Cumulative infant HIV infection rates per 100 infants (95%CI) and by maternal CD4 count and regimen are shown in the table. The log-rank test showed no difference in infection rates by maternal CD4 (p = 0.89) or by regimen (p = 0.83). The overall rate at 12 months for females was 7.4 (95%CI 4.6 to 11.9), males 4.5 (95%CI 2.5 to 8.1) (p = 0.15).

 

Age

0–7 days

6 weeks

3 months

6 months

12 months

Transmission events

12

19

20

24

27

All infants

(n = 497)

2.4

(1.4–4.2)

3.9

(2.5–6.0)

4.1

(2.7–6.3)

5.0

(3.4–7.3)

5.9

(4.0–8.5)

CD4 ≤250

(n = 118)

3.4

(1.3–8.8)

4.3

(1.8–10.0)

5.2

(2.4–11.2)

5.2

(2.4–11.2)

6.7

(3.2–13.9)

CD4>250

(n = 379)

2.1

(1.1–4.2)

3.8

(2.2–6.3)

3.8

(2.2–6.3)

4.9

(3.1–7.7)

5.5

(3.6–8.4)

Nevirapine

(n = 178)

1.1

(0.3–4.4)

3.4

(1.6–7.5)

3.4

(1.6–7.5)

5.2

(2.8–9.8)

5.9

(3.2–10.6)

Nelfinavir

(n = 201)

3.0

(1.4–6.5)

4.0

(2.0–7.9)

4.0

(2.0–7.9)

4.6

(2.4–8.6)

5.2

(2.8–9.5)

 

Conclusions:  Low 12-month infant HIV transmission rates were achieved using maternal HAART from late pregnancy through 6 months of breastfeeding. There was no difference in transmission based on maternal CD4 or regimen. Further assessment—adherence to aniretrovirals, the optimal timing for breastfeeding cessation, HIV-free survival, and drug resistance in maternal and infant HIV isolates—is necessary to determine whether HAART is a feasible, acceptable, safe, and efficacious strategy for PMTCT among breastfeeding women, particularly those not meeting WHO treatment criteria.