HIV-1 mother-to-child transmission and drug resistance among Brazilian pregnant women with high access to diagnosis and prophylactic measures.
BACKGROUND
A high-coverage public health prenatal program (70,000 women/year) from central western Brazil/Goias State has represented a unique opportunity for the early diagnosis of HIV-1 and implementation of strategies to prevent mother-to-child transmission (MTCT).


OBJECTIVE
To investigate MTCT among a prospective cohort of HIV-1 infected mothers/exposed infants.


METHODS
142 mothers/their 149 infants (2008-2010) were investigated regarding maternal viral load, CD4(+)cell counts, HIV-1 pol sequences; infants' HIV-1 RNA tests (30/120 days), sequential anti-HIV-1/2 serology. HIV-1 subtypes were assigned by REGA. Transmitted drug resistance was identified by the Calibrated Population Resistance tool, secondary resistance by Stanford HIV-1 Drug Resistance/International AIDS Society databases.


RESULTS
Mothers (median age=24 years; 25/142 adolescents) were diagnosed during prenatal care (2008-2010) or previously (1994-2007). Recent cases were younger, mostly asymptomatic. Undetectable viremia and MTCT prophylaxis predominated in formerly diagnosed mothers. Recent cases had higher subtype C prevalence. One naive patient had transmitted resistance; ten antiretroviral-experienced patients had secondary resistance: 6 from MTCT prophylaxis, 4 under HAART. Late disclosure of diagnosis, vaginal delivery, breastfeeding, lack of oral zidovudine were observed in the three MTCT cases (3/149; 2.01%). Two of three infected infants harbored subtype C; infected infants/mothers did not have drug resistance mutations. Two of the transmitting-mothers had viremia <1000 copies/ml. Among exposed-uninfected infants the median time to seroreversion was 12 months.


CONCLUSIONS
In this study delayed disclosure of diagnosis, partial/no preventive measures, drug resistance among asymptomatic women under prophylaxis and MTCT in low viremic mothers raise concerns. The expansion of subtype C infection corroborates surveillance of HIV-1 diversity in this region.
Tropical Pathology and Public Health Institute/Federal University of Goias, Brazil.
Keila Correia
KC
Alcântara
Janaína Bacelar Accioli
JB
Lins
Maly
M
Albuquerque
Letícia Mara
LM
Aires
Ludimila Paula Vaz
LP
Cardoso
Ana Lúcia
AL
Minuzzi
Mariane Martins Araújo
MM
Stefani
D000293:Adolescent; D000328:Adult; D001938:Brazil / Q000453:epidemiology; D018791:CD4 Lymphocyte Count; D015331:Cohort Studies; D024882:Drug Resistance, Viral; D005260:Female; D005838:Genotype; D015658:HIV Infections / Q000635:transmission* / Q000821:virology*; D015497:HIV-1 / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D006801:Humans; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical; D008297:Male; D008969:Molecular Sequence Data; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000821:virology*; D011446:Prospective Studies; D012307:Risk Factors; D017422:Sequence Analysis, DNA; D019562:Viral Load; D055815:Young Adult; D054302:pol Gene Products, Human Immunodeficiency Virus / Q000235:genetics
D054302:pol Gene Products, Human Immunodeficiency Virus