Maternal HIV-1 viral load and vertical transmission of infection: The Ariel Project for the prevention of HIV transmission from mother to infant

Abstract

Most HIV-1 infections of children result from mother-to-infant transmission, which may occur perinatally or postnatally, as a consequence of breast feeding. In this study, the influence of maternal viral load on transmission of infection to infants from non-breast-feeding mothers was examined using samples of plasma and peripheral blood mononuclear cells (PBMCs) collected at several time points during pregnancy and the 6-month period after delivery. These samples were analyzed by several quantitative methods, including virus cultures of PBMCs and polymerase chain reaction (PCR) assays for HIV-1 RNA in plasma and DNA in PBMCs. The risk of transmission increased slightly with a higher viral load, but transmission and nontransmission occurred over the entire range of values for each assay. No threshold value of virus load was identified which discriminated between transmitters and nontransmitters. We also noted a significant rise in viral load and a decline in CD4+ lymphocytes in the six months after delivery. These findings suggest that a high maternal viral load is insufficient to fully explain vertical transmission of HIV-1. Additional studies are needed to examine the post-partum increase in viremia.

Occupationally Acquired Human Immunodeficiency Virus (HIV) Infection: National Case Surveillance Data During 20 Years of the HIV Epidemic in the United States

“…been observed in cases of perinatally acquired as well as in at least one case of occupationally acquired HIV infection. [41][42][43] Among the documented cases of occupationally acquired HIV infection described here, information on viral titers at the time of occupational exposures was not generally available. However, 11% of the cases involved a source patient with asymptomatic HIV infection, which is associated with lower plasma viral titers.…”

Role of placenta in the vertical transmission of human immunodeficiency virus

“…17 No threshold value of virus load have been identified to distinguish between transmitting and nontransmitting mothers. 18 However, high maternal viral load is insufficient to completely explain vertical transmission of HIV-1.…”

Role of male partners in the prevention of mother-to-child HIV transmission

“…33,34 As programs become more successful in diagnosing and providing prophylaxis for or treating HIV-infected women at their first antenatal visit, these acute maternal infections threaten to reduce the impact of PMTCT interventions and greatly hinder progress toward virtual elimination of HIV. In high HIV burden settings, the prevalence of HIV discordance remains high with nearly half of HIV-infected individuals being in HIV-discordant relationships.…”