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Very Low Risk of Mother-to-Child Transmission in Women on HAART Who Achieve Viral Suppression: The UK and Ireland, 2000 to 2006
Claire Townsend*1, M Cortina-Borja1, C Peckham1, A de Ruiter2, H Lyall3, and P Tookey1
1Univ Coll London Inst of Child Hlth, UK; 2St Thomas` Hosp, London, UK; and 3St Mary`s Hosp, London, UK
Background: Mother-to-child HIV transmission (MTCT) rates
have declined to 1 to 2% in Europe in recent years. With the success of HAART
in suppressing HIV RNA viral load, women are increasingly opting for vaginal
delivery, instead of elective caesarean section. In the United Kingdom, zidovudine monotherapy and elective caesarean section is also offered as an
option for some women who do not require HAART for their own health and have
low viral loads.
Methods: Births to women with diagnosed HIV infection in
the United Kingdom and Ireland are notified to the National Study of HIV in
Pregnancy and Childhood through confidential, active surveillance schemes. MTCT
rates in infants born between 2000 and 2006 were explored with an emphasis on ART,
mode of delivery, and viral load (closest to delivery). Analyses were carried
out in Stata 9.0.
Results: Infection status was available for 86.8% of
infants (5136 of 6127). The MTCT rate was 1.1% (61 of 5316, 95%CI 0.9% to 1.5%)
overall, and 0.8% (40 of 5027, 95%CI 0.6 to 1.1%) in infants whose mothers received
ART for at least 14 days. There was no significant difference in MTCT rates
between women on HAART who had an elective caesarean section (17 of 2337, 0.7%,
95%CI 0.4 to 1.2%) or a planned vaginal delivery (4 of 565, 0.7%, 95%CI 0.2 to 1.8%),
and those on prophylactic zidovudine (prescribed according to the British HIV
Association [BHIVA] Guidelines) who had an elective caesarean section (0 of 467,
0%, upper 95%CI 0.8%; p = 0.094). In these 3 groups, the proportions of
women with viral load <50 copies/mL were 59% (1341 of 2276), 80% (508 of 634),
and 23% (105 of 447), respectively. Only 3 transmissions were reported among 2202
infants born to women on HAART with viral load <50 copies/mL (0.1%, 95%CI 0
to 0.4%): 2 were born by elective caesarean section (MTCT rate 0.2%, 2 of 1180)
and 1 by planned vaginal delivery (MTCT rate 0.2%, 1 of 419). Of the 3 infected
infants, 2 had positive polymerase chain reaction (PCR) tests at births,
suggesting in utero transmission (the other was negative at birth).
Conclusions: There was no difference in MTCT rates according
to the management strategies outlined in the BHIVA Guidelines: HAART with
elective caesarean section or planned vaginal delivery, and zidovudine
monotherapy with elective caesarean section. The risk of MTCT in appropriately
managed pregnancies in the United Kingdom and Ireland is very low.
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