Epidemiology of HIV infection in the newborn.
Vertical transmission of HIV infection can take place in utero, during delivery and postnatally through breastfeeding, with about three-quarters of infections occurring around the time of delivery in non-breastfeeding populations. In Europe, in the absence of specific interventions, the vertical transmission rate was 15-20%. High maternal load is the major risk factor for both intra-uterine and intra-partum mother-to-child transmission. Prematurity is the most common adverse neonatal outcome associated with maternal HIV infection. Earlier diagnosis of paediatric HIV infection than previously available is now possible with virological tests, particularly HIV DNA polymerase chain reaction. An estimated one fifth of infected children will have been diagnosed with AIDS or have died by 12 months of age, rising to a third by 6 years of age. Surgical and therapeutic interventions are effective in reducing vertical transmission risk, in addition to the avoidance of breastfeeding. Caesarean section delivery before labour and before rupture of membranes approximately halves the risk of transmission, while prophylactic zidovudine therapy according to the ACTG076 regimen reduces transmission by up to two-thirds, transmission is reduced even further with both interventions. Trials of short-course zidovudine regimens show their effectiveness in reducing vertical transmission, in breastfeeding and non-breastfeeding populations. Nevirapine has been shown to be significantly more effective than short course zidovudine regimens in breastfeeding populations, but is still under evaluation in non-breastfeeding populations additionally receiving routine anti-retroviral prophylaxis. Reports of a small number of serious adverse events in uninfected children exposed in utero or neonatally to antiretroviral therapy need further investigation. Trials of vitamin A supplementation to reduce vertical transmission have had negative results, while the effectiveness of vaginal lavage and passive immune therapy in reducing vertical transmission remains uncertain.
Thorne
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Institute of Child Health, Department of Paediatric Epidemiology, 30 Guildford Street, London, UK.
Newell
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ML
D000328:Adult; D017954:Africa South of the Sahara / Q000453:epidemiology; D001210:Asia, Southeastern / Q000453:epidemiology; D005060:Europe / Q000453:epidemiology; D005260:Female; D015658:HIV Infections / Q000453:epidemiology* / Q000517:prevention & control / Q000635:transmission; D006801:Humans; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical / Q000706:statistics & numerical data*; D009656:North America / Q000453:epidemiology; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000453:epidemiology*; D012307:Risk Factors