Population attributable fractions for late postnatal mother-to-child transmission of HIV-1 in Sub-Saharan Africa.
OBJECTIVE
Assess population attributable fractions (PAFs) for late postnatal transmission (LPT) of HIV-1 in a cohort of HIV-1-exposed infants.


METHODS
We used data established from a risk factor analysis of LPT (negative HIV-1 results through the 4-6 week visit, but positive assays thereafter through the 12-month visit) from a perinatal clinical trial conducted in 3 sub-Saharan countries. PAFs were calculated as the proportions of excess LPTs attributed to identified risk factors.


RESULTS
For the cohort of 1317 infants, 206 (15.6%) had only low maternal CD4 counts (<200 cells/mm), 332 (25.2%) had only high maternal plasma viral loads (VLs) (>50,000 copies/mL), and 81 (6.2%) had both low CD4 counts and high VLs. Their PAFs were 26.0% [95% confidence interval (CI): 12.0% to 36.0%], 37.0% (95% CI: 22.0% to 51.0%), and 16.0% (95% CI: 6.0% to 25.0%), respectively.


CONCLUSIONS
Our PAF analysis illustrates the public health impact of the substantial proportion of LPTs accounted for by high-risk women with both low CD4 counts and high VLs. In light of these results, access to and use of antiretroviral therapy by high-risk HIV-1-infected pregnant women is essential. Additional strategies to reduce LPT for those not meeting criteria for antiretroviral therapy should be implemented.
Chen
Ying Q
YQ
Statistical Center for HIV/AIDS Research and Prevention, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA. yqchen@scharp.org
Young
Alicia
A
Brown
Elizabeth R
ER
Chasela
Charles S
CS
Fiscus
Susan A
SA
Hoffman
Irving F
IF
Valentine
Megan
M
Emel
Lynda
L
Taha
Taha E
TE
Goldenberg
Robert L
RL
Read
Jennifer S
JS
D017954:Africa South of the Sahara / Q000453:epidemiology; D018791:CD4 Lymphocyte Count; D015331:Cohort Studies; D005260:Female; D015658:HIV Infections / Q000453:epidemiology / Q000635:transmission* / Q000821:virology; D015497:HIV-1; D006801:Humans; D007223:Infant; D018445:Infectious Disease Transmission, Vertical; D011247:Pregnancy; D012307:Risk Factors