Mother-to-Child HIV Transmission among Pregnant Women in a City with the Highest Rates of HIV in Brazil

Abstract

Objective Most of the HIV pediatric infections are acquired through mother-to-child transmission (MTCT). Porto Alegre is a state capital of Brazil that had a HIV MTCT rate of 4.1% in 2013 and the highest rate of HIV-infected pregnant women in the country during 2018. Zidovudine and nevirapine have been used in Brazil for high-risk newborns since 2012. The aim of the study was to investigate HIV MTCT rate and the factors associated with HIV transmission at a hospital that is a reference center for HIV-infected mothers in Porto Alegre, after the introduction of this policy. Study Design This retrospective cohort study included all HIV-exposed infants born between February 2013 and December 2016 at the Hospital de Clínicas de Porto Alegre. Student's t-test or Fisher's exact test was used to compare variables between HIV-infected and uninfected groups of newborns. Poisson's regression with robust variance was used to determine the factors associated with HIV MTCT. Results A total of 375 newborns were exposed to HIV, with an outpatient loss of 14.4% (n = 54). The HIV MTCT rate was 2.18% (n = 7), with four infected during the intrauterine period. The risk factors for MTCT were no prenatal care (relative risk [RR] = 9.4; 95% confidence interval [CI]: 2.0–44.3), late maternal HIV diagnosis in the peripartum period (RR = 16.3; 95% CI: 3.6–73.0), syphilis infection during pregnancy (RR = 9.3; 95% CI: 2.1–40.3), maternal viral load >1,000 copies/mL in the third trimester or peripartum period (RR = 9.5; 95% CI: 1.7–50.5), and lack of or inappropriate antiretroviral therapy during pregnancy (RR = 8.2; 95% CI: 1.6–41.4). Conclusion MTCT rate was 2.18%. With the institution of two-drug prophylaxis for high-risk newborns, persistent cases HIV MTCT were predominantly found among women with absence of antenatal care, late HIV diagnosis, syphilis coinfection, high viral load, and inadequate ARV therapy during pregnancy. Although zidovudine and nevirapine were administered postnatally to high-risk newborns, this regimen could not prevent transplacental transmission. Key Points

Clinical–Epidemiological Characteristics and IFITM-3 (rs12252) Variant Involvement in HIV-1 Mother-to-Children Transmission Susceptibility in a Brazilian Population

“…HIV-1 MTCT susceptibility presents itself as a multifactorial and complex event, dependent of viral, maternal, and pediatric variables. In our study population, maternal characteristics such as low age at delivery, late diagnosis, no use of ART during pregnancy/delivery, and detectable VL in the last pregnancy trimester are associated with increased susceptibility to HIV-1 MTCT, corroborating with previous studies [ 32 , 33 , 34 ].…”

“…Younger mothers may lack experience to care for themselves and their infants, and possibly have a less favorable socioeconomic status than older women [ 31 ]. These facts can directly impact other preventive measures, leading to late diagnosis and inappropriate ART use, maximizing the transmission risks, as observed in our and other populations [ 33 , 34 , 35 ].…”

Mother-to-Child Transmission of HIV Within 24 Months After Delivery in Women Initiating Lifelong Antiretroviral Therapy Pre/Post-Conception or Postnatally; Effects of Adolescent Girl and Young Woman Status and Plasma Viremia Late in Pregnancy

“…Antenatal HIV RNA > 1,000 copies/ml was independently associated with MTCT risk: OR (CI): 9.3 (2.6-43.1), thus complementing previous findings (49,(51)(52)(53). A Brazilian study showed an almost similar degree of risk but the only difference was most of babies were infected during the IU and not PP-MTCT as in our case study (54).…”

A transmissão vertical do HIV em Porto Alegre, Brasil: um estudo caso-controle / The vertical transmission of HIV in Porto Alegre, Brazil: a case-control study

“…28 Os dados colhidos mostram peculiaridade, não encontrada com frequência na literatura, ou seja, a associação entre o número de gestações da mulher, após o diagnóstico do HIVe a TVHIV. Estudos realizados anteriormente com a mesma população já apontavam nessa direção29 , ou seja, o número de gestações em gestante portadora do HIV, após esse diagnóstico, indicaria um risco acrescido à TVHIV.…”