Background and Methods We examined the influence of viral load in relation to other risk factors for the heterosexual transmission of human immunodeficiency virus type 1 (HIV-1). In a community-based study of 15,127 persons in a rural district of Uganda, we identified 415 couples in which one partner was HIV-1–positive and one was initially HIV-1–negative and followed them prospectively for up to 30 months. The incidence of HIV-1 infection per 100 person-years among the initially seronegative partners was examined in relation to behavioral and biologic variables. Results The male partner was HIV-1–positive in 228 couples, and the female partner was HIV-1–positive in 187 couples. Ninety of the 415 initially HIV-1–negative partners seroconverted (incidence, 11.8 per 100 person-years). The rate of male-to-female transmission was not significantly different from the rate of female-to-male transmission (12.0 per 100 person-years vs. 11.6 per 100 person-years). The incidence of seroconversion was highest among ...

https://www.nejm.org/doi/pdf/10.1056/NEJM200003303421303

Viral Load and Heterosexual Transmission of Human Immunodeficiency Virus Type 1

https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(99)80008-7.pdf

Intrapartum and neonatal single-dose nevirapine compared with zidovudine for prevention of mother-to-child transmission of HIV-1 in Kampala, Uganda: HIVNET 012 randomised trial

Each year, an estimated 590,000 infants acquire human immunodeficiency virus type 1 (HIV) infection from their mothers, mostly in developing countries that are unable to implement interventions now standard in the industrialized world. In resource-poor settings, the HIV pandemic has eroded hard-won gains in infant and child survival. Recent clinical trial results from international settings suggest that short-course antiretroviral regimens could significantly reduce perinatal HIV transmission worldwide if research findings could be translated into practice. This article reviews current knowledge of mother-to-child HIV transmission in developing countries, summarizes key findings from the trials, outlines future research requirements, and describes public health challenges of implementing perinatal HIV prevention interventions in resource-poor settings. Public health efforts must also emphasize primary prevention strategies to reduce incident HIV infections among adolescents and women of childbearing age. Successful implementation of available perinatal HIV interventions could substantially improve global child survival.

http://www.engenderhealth.org/files/pubs/acquire-digital-archive/6.0_integrate_fp-lapms/6.2_resources/6.2.4_tools/fhi-contraception-cd/resources/decockarticle.pdf

Prevention of mother-to-child HIV transmission in resource-poor countries: translating research into policy and practice.

Pregnant women in malarious areas may experience a variety of adverse consequences from malaria infection including maternal anemia, placental accumulation of parasites, low birth weight (LBW) from prematurity and intrauterine growth retardation (IUGR), fetal parasite exposure and congenital infection, and infant mortality (IM) linked to preterm-LBW and IUGR-LBW. We reviewed studies between 1985 and 2000 and summarized the malaria population attributable risk (PAR) that accounts for both the prevalence of the risk factors in the population and the magnitude of the associated risk for anemia, LBW, and IM. Consequences from anemia and human immunodeficiency virus infection in these studies were also considered. Population attributable risks were substantial: malaria was associated with anemia (PAR range = 3-15%), LBW (8-14%), preterm-LBW (8-36%), IUGR-LBW (13-70%), and IM (3-8%). Human immunodeficiency virus was associated with anemia (PAR range = 12-14%), LBW (11-38%), and direct transmission in 20-40% of newborns, with direct mortality consequences. Maternal anemia was associated with LBW (PAR range = 7-18%), and fetal anemia was associated with increased IM (PAR not available). We estimate that each year 75,000 to 200,000 infant deaths are associated with malaria infection in pregnancy. The failure to apply known effective antimalarial interventions through antenatal programs continues to contribute substantially to infant deaths globally.

The burden of malaria in pregnancy in malaria-endemic areas.

Context The Women and Infants Transmission Study is a prospective natural history study that has been enrolling HIV-1-infected pregnant women and their infants since 1989. Objective To evaluate the impact of different antiretroviral regimens on perinatal HIV-1 transmission at the population level. Design Prospective cohort study. Plasma HIV-1 RNA levels were serially measured in 1542 HIV-1-infected women with singleton live births between January 1990 and June 2000. Main outcome measure HIV-1 status of the infant. Results HIV-1 transmission was 20.0% (95% confidence interval [CI], 16.1%-23.9%) for 396 women who not receiving prenatal antiretroviral therapy; 10.4% (95% CI, 8.2%-12.6%) for 710 receiving zidovudine monotherapy; 3.8% (95% CI, 1.1%-6.5%) for 186 receiving dual antiretroviral therapy with no or one highly active drug (Multi-ART); and 1.2% (95% CI, 0-2.5%) for 250 receiving highly active antiretroviral therapy (HAART). Transmission also varied by maternal delivery HIV RNA level: 1.0% for 30,000 copies/mL (p =.0001 for trend). The odds of transmission increased 2.4-fold (95% CI, 1.7-3.5) for every log10 increase in delivery viral load. In multivariate analyses adjusting for maternal viral load, duration of therapy, and other factors, the odds ratio for transmission for women receiving Multi-ART and HAART compared with those receiving ZDV monotherapy was 0.30 (95% CI, 0.09-1.02) and 0.27 (95% CI, 0.08-0.94), respectively. Conclusion Levels of HIV-1 RNA at delivery and prenatal antiretroviral therapy were independently associated with transmission. The protective effect of therapy increased with the complexity and duration of the regimen. HAART was associated with the lowest rates of transmission.

Combination antiretroviral strategies for the treatment of pregnant HIV-1-infected women and prevention of perinatal HIV-1 transmission.

https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(98)10411-7.pdf

Short-course zidovudine for perinatal HIV-1 transmission in Bangkok, Thailand: a randomised controlled trial

In the absence of breast-feeding perinatal HIV transmission can occur either in utero or during the intrapartum period. Findings are presented from a prospective cohort study conducted to measure the proportion of HIV-1-infected infants infected in utero and intrapartum the relationship between transmission risk factors and time of transmission and the population-attributable fractions for maternal viral load. Findings are based upon data for 218 formula-fed infants of HIV-1-infected untreated mothers with known infection outcome and a birth HIV-1-positive DNA PCR test result. 49 infected infants with an HIV-1 birth PCR result 12 (24.5%) were presumed to have been infected in utero and 37 (75.5%) were presumed to have been infected intrapartum. In utero transmission was presumed to have occurred if the blood sample drawn within 72 hours of birth was HIV-1-positive by PCR. Intrapartum transmission was presumed to have occurred if the birth sample tested negative and a later sample was HIV-1-positive. The estimated absolute overall HIV transmission rate was 22.5%; 5.5% in utero transmission and 18% intrapartum transmission. High maternal HIV-1 viral load was a major risk factor for both in utero and intrapartum transmission. Low birth weight was associated with in utero transmission while low maternal natural killer cell and CD4+ T-lymphocyte percentages were associated with intrapartum transmission. The population-attributable fraction for intrapartum transmission associated with viral load higher than 10000 copies/ml was 69%.

Maternal viral load and timing of mother-to-child HIV transmission Bangkok Thailand.

To determine the rate and risk factors for human immunodeficiency virus (HIV)-1 subtype E perinatal transmission, with focus on virus load, pregnant HIV-infected women and their formula-fed infants were followed prospectively in Bangkok. Of 281 infants with known outcome, 68 were infected (transmission rate, 24.2%; 95% confidence interval, 19.3%-29.6%). Transmitting mothers had a 4.3-fold higher median plasma HIV RNA level at delivery than did nontransmitters (P 10,000 copies/mL. Although risk is multifactorial, high maternal virus load at delivery strongly predicts transmission. This may have important implications for interventions designed to reduce perinatal transmission.

https://www.jstor.org/stable/info/30117311

Maternal Virus Load and Perinatal Human Immunodeficiency Virus Type 1 Subtype E Transmission, Thailand

Context.—Most prior studies of the human immunodeficiency virus (HIV) epidemic
in Thailand have focused on commercial sex encounters; however, because the
epidemic increasingly concerns stable heterosexual relationships, determining
risk factors for this form of transmission is warranted.Objectives.—To determine temporal trends in HIV prevalence, risk factors for HIV
seropositivity, and rates of partner serodiscordance for pregnant women in
Bangkok, Thailand.Design.—Retrospective review of hospital antenatal clinic HIV test results from
1991 through 1996. Baseline demographic and behavioral risk factors for HIV
were assessed for subjects enrolled from November 1992 through March 1994.Setting.—Two Bangkok hospitals with routine antenatal clinic HIV counseling and
testing.Participants.—The HIV-positive pregnant women enrolled in a perinatal HIV transmission
study and their partners and HIV-negative pregnant controls.Results.—From 1991 through 1996, antenatal clinic HIV seroprevalence increased
from 1.0% to 2.3%. On multivariate analysis of data from 342 HIV-positive
and 344 HIV-negative pregnant women, more than 1 lifetime sex partner, history
of a sexually transmitted disease, and a high-risk sex partner were the most
important factors for seropositivity (all P<.001).
Twenty-six percent of partners of HIV-positive women were HIV negative. Women
reporting more than 1 lifetime sex partner were more likely to have an HIV-negative
partner than women reporting only 1 (45% vs 8%; relative risk, 5.5; 95% confidence
interval, 3.2-9.5; P<.001); women reporting no
high-risk behaviors were less likely to have an HIV-negative partner (10%
vs 44%; relative risk, 0.2; 95% confidence interval, 0.1-0.4; P <.001).Conclusions.—Prevalence of HIV in pregnant women has increased steadily in Bangkok
from 1991 through 1996. Sex with current partners was the only identified
risk exposure for about half (52%) of the HIV-positive women. Although few
HIV-positive pregnant women reported high-risk behaviors, more than 1 lifetime
partner and a partner with high-risk behavior were strong risk factors for
seropositivity. Together with the unexpected finding that one fourth of partners
of seropositive pregnant women were seronegative, these data emphasize that
women in the general population are at risk for HIV because of the risk behavior
of both current and previous partners.

https://jamanetwork.com/journals/jama/articlepdf/187694/joc71354.pdf

Pratharn Chinayon

Papers

Short-course zidovudine for perinatal HIV-1 transmission in Bangkok, Thailand: a randomised controlled trial

Maternal viral load and timing of mother-to-child HIV transmission Bangkok Thailand.

Maternal Virus Load and Perinatal Human Immunodeficiency Virus Type 1 Subtype E Transmission, Thailand

HIV Prevalence, Risk, and Partner Serodiscordance Among Pregnant Women in Bangkok