Risk factors for late postnatal transmission of human immunodeficiency virus type 1 in sub-Saharan Africa.
BACKGROUND
We conducted secondary data analyses of a clinical trial (HIVNET 024) to assess risk factors for late postnatal transmission (LPT) of human immunodeficiency virus type 1 (HIV-1) through breast-feeding.


METHODS
Data regarding live born, singleton infants of HIV-1-infected mothers were analyzed. The timing of HIV-1 transmission through 12 months after birth was defined as: in utero (positive HIV-1 RNA results at birth), perinatal/early postnatal (negative results at birth, positive at 4-6 week visit), or LPT (negative results through the 4-6 week visit, but positive assays thereafter through the 12-month visit). HIV-1-uninfected infants were those with negative HIV-1 enzyme immunoassay results at 12 months of age, or infants with negative HIV-1 RNA results throughout follow-up.


RESULTS
Of 2292 HIV-1-infected enrolled women, 2052 mother/infant pairs met inclusion criteria. Of 1979 infants with HIV-1 tests, 404 were HIV-1-infected, and 382 had known timing of infection (LPT represented 22% of transmissions). Further analyses of LPT included infants who were breast-feeding at the 4-6 week visit (with negative HIV-1 results at that visit) revealed 6.9% of 1317 infants acquired HIV-1 infection through LPT by 12 months of age. More advanced maternal HIV-1 disease at enrollment (lower CD4 counts, higher plasma viral loads) were the factors associated with LPT in adjusted analyses.


CONCLUSIONS
In this breast-feeding population, 6.9% of infants uninfected at 6 weeks of age acquired HIV-1 infection by 12 months. Making interventions to decrease the risk of LPT of HIV-1 available and continuing research regarding the mechanisms of LPT (so as to develop improved interventions to reduce such transmission) remain essential.
Chasela
Charles
C
University of North Carolina Project, Kamuzu Central Hospital, Lilongwe, Malawi. charles.chasela@ucd.ie
Chen
Ying Qing
YQ
Fiscus
Susan
S
Hoffman
Irving
I
Young
Alicia
A
Valentine
Megan
M
Emel
Lynda
L
Taha
Taha E
TE
Goldenberg
Robert L
RL
Read
Jennifer S
JS
D000293:Adolescent; D000328:Adult; D017954:Africa South of the Sahara / Q000453:epidemiology; D000914:Antibodies, Viral / Q000097:blood; D001942:Breast Feeding / Q000009:adverse effects*; D018791:CD4 Lymphocyte Count; D005260:Female; D015658:HIV Infections / Q000453:epidemiology* / Q000635:transmission*; D015497:HIV-1 / Q000302:isolation & purification*; D006801:Humans; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical; D009035:Mothers; D012367:RNA, Viral / Q000097:blood; D012307:Risk Factors; D019562:Viral Load
D000914:Antibodies, Viral; D012367:RNA, Viral