Preferential in-utero transmission of HIV-1 subtype C as compared to HIV-1 subtype A or D.
OBJECTIVE
To determine whether different HIV-1 genotypes present in a single cohort, in Dar es Salaam, Tanzania, showed differences in timing for transmission from mothers to their infants.


METHODS
We determined the maternal viral load, transmission time, and the HIV-1 envelope (env) subtype of 253 HIV-1-infected infants enrolled in a randomized double-blind placebo-controlled trial to examine the efficacy of vitamins in decreasing mother-to-child transmission in Tanzania. Classification of HIV-1 positivity in utero was based on PCR results at birth. Infants were classified as intrapartum infected if they scored negative for the sample collected at birth and positive for the sample collected at 6 weeks of age.


RESULTS
We found significant differences in the distribution of transmission time according to subtype. A higher proportion of HIV-1 with subtype C env (C-env) was transmitted in utero than HIV-1 with subtype A env (A-env), subtype D env (D-env), or both combined.


CONCLUSIONS
The identification of patterns of mother-to-child transmission times among HIV-1 genotypes may be useful in the selection of drug regimens for chemoprophylaxis. Based on our results, the efficacy of regimens administered only at labor may not protect as large a fraction of infants born in geographical regions with subtype C-env epidemics as compared to epidemics in regions where subtypes A-env and D-env predominate in the population.
Renjifo
Boris
B
Department of Immunology and Infectious Diseases and the Harvard AIDS Institute, Harvard School of Public Health, Boston, Massachusetts 02115, USA.
Gilbert
Peter
P
Chaplin
Beth
B
Msamanga
Gernard
G
Mwakagile
Davis
D
Fawzi
Wafaie
W
Essex
Max
M
D000293:Adolescent; D000328:Adult; D001942:Breast Feeding; D004311:Double-Blind Method; D005260:Female; D015752:Genes, env / Q000235:genetics; D005838:Genotype; D015658:HIV Infections / Q000097:blood / Q000635:transmission*; D015497:HIV-1 / Q000235:genetics*; D006801:Humans; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical / Q000517:prevention & control; D011247:Pregnancy; D012307:Risk Factors; D013997:Time Factors; D019562:Viral Load; D014815:Vitamins / Q000008:administration & dosage
D014815:Vitamins