Impact of GB virus type C infection on mother-to-child HIV transmission in the Women and Infants Transmission Study Cohort

BACKGROUND: GB virus type C (GBV-C) viraemia is associated with a beneficial outcome in HIV-infected individuals in several though not all studies. GBV-C viraemia was examined in a matched case-control study of 133 HIV-infected pregnant women who transmitted HIV to their infants ('cases') and 266 non-transmitting controls. METHODS: HIV-infected children and controls were pair-matched for high-risk delivery, race and year of delivery. GBV-C status was determined in maternal plasma samples obtained at or within 3 months of delivery. RESULTS: Pregnant women with GBV-C viraemia (11% of those studied) had lower HIV RNA levels (P=0.01) and higher CD4 percentages (P=0.0006) [corrected] than women without GBV-C. A trend towards decreased mother-to-child transmission in the multivariate analysis was observed among GBV-C viraemic women delivering after highly active antiretroviral therapy (HAART) became available [odds ratio (OR) 0.30, 95% confidence interval (CI) 0.08-1.05; P=0.06], but not in women delivering prior to the widespread use of HAART. CONCLUSIONS: GBV-C viraemia was associated with a beneficial effect on CD4 percentage and HIV RNA level in these pregnant women, and was also associated with a trend towards reduced risk of mother-to-child HIV transmission among women after HAART became available. Further studies with larger or multiple cohorts are necessary to assess possible benefits in this population.     

Vertical transmission of HIV-1 in Poland

The aim of our study was to evaluate changes in vertical transmission of HIV infection in Poland after introducing zidovudine prophylactic strategies. Data from the Department of Children's Infectious Diseases (a paediatric HIV referral centre) at the Medical University, Warsaw was studied. Since 1989 vertical transmission of HIV-1 has been studied in 100 children born to 91 HIV-positive mothers (2 sets of twins). Zidovudine therapy, mode and timing of delivery and their relationship to perinatal HIV-1 infection were analysed. From 1989 to 1994 the transmission rate was 31.5%. Since 1995, when recommendations based on ACTG 076 were issued, a decline in a transmission rate to 19.6% was reported. 62% (32 out of 52) mother-infant pairs received zidovudine therapy. None of those children have become HIV infected. Zidovudine chemoprophylaxis regimen reduces the risk for mother to child transmission. It should be recommended for all HIV-infected pregnant women or women in labour and their infants.     

Reduced mother-to-child transmission of HIV associated with infant but not maternal GB virus C infection

BACKGROUND: Prolonged coinfection with GB virus C (GBV-C) has been associated with improved survival in human immunodeficiency virus (HIV)-infected adults. We investigated whether maternal or infant GBV-C infection was associated with mother-to-child transmission (MTCT) of HIV-1 infection. METHODS: The study population included 1364 HIV-infected pregnant women enrolled in 3 studies of MTCT of HIV in Bangkok, Thailand (the studies were conducted from 1992-1994, 1996-1997, and 1999-2004, respectively). We tested plasma collected from pregnant women at delivery for GBV-C RNA, GBV-C antibody, and GBV-C viral genotype. If GBV-C RNA was detected in the maternal samples, the 4- or 6-month infant sample was tested for GBV-C RNA. The rates of MTCT of HIV among GBV-C-infected women and infants were compared with the rates among women and infants without GBV-C infection. RESULTS: The prevalence of GBV-C RNA in maternal samples was 19%. Of 245 women who were GBV-C RNA positive, 101 (41%) transmitted GBV-C to their infants. Of 101 infants who were GBV-C RNA positive, 2 (2%) were infected with HIV, compared with 162 (13%) of 1232 infants who were GBV-C RNA negative (odds ratio [OR] adjusted for study, 0.13 [95% confidence interval {CI}, 0.03-0.54]). This association remained after adjustment for maternal HIV viral load, receipt of antiretroviral prophylaxis, CD4(+) count, and other covariates. MTCT of HIV was not associated with the presence of GBV-C RNA (adjusted OR [aOR], 0.94 [95% CI, 0.62-1.42]) or GBV-C antibody (aOR, 0.90 [95% CI, 0.54-1.50]) in maternal samples. CONCLUSIONS: Reduced MTCT of HIV was significantly associated with infant acquisition of GBV-C but not with maternal GBV-C infection. The mechanism for this association remains unknown.     

Surveillance of mother-to-child transmission prevention programmes at immunization clinics: the case for universal screening

BACKGROUND: Surveillance programmes for prevention of mother-to-child transmission of HIV (PMTCT) fail to quantify numbers of infant HIV infections averted, often because of poor postnatal follow-up. Additionally, infected infants are often not identified early and only gain access to comprehensive HIV care and treatment late in their disease. METHODS: Anonymous, unlinked, HIV prevalence testing was conducted on dried blood spot (DBS) samples from all infants attending 6 week immunization clinics at seven primary health care clinics offering PMTCT. Samples were tested for HIV antibodies (indicating maternal HIV infection) and those determined to be from HIV-exposed infants were tested for HIV RNA by polymerase chain reaction. Infant and child mortality rates were determined using birth histories. RESULTS: Samples were collected from 2489 infants aged 4-8 weeks. HIV antibodies were identified in 931 infants [37.4%; 95% confidence interval (CI), 35.4-39.4], of whom 188 were HIV RNA positive. The estimated vertical transmission rate (VTR) was 20.2% (95% CI, 17.8-23.1%); 7.5% of all infants at this age were infected. Amongst mothers who reported that they had taken single-dose nevirapine for PMTCT, VTR was 15.0%. Amongst women who reported being HIV uninfected but whose infants had HIV antibodies, VTR was 30.5%. Infant mortality rates in KwaZulu Natal increased from 28/1000 live births in 1990-1994 to 92/1000 in 2000-2004. CONCLUSIONS: Anonymous HIV prevalence screening of all infants at immunization clinics is feasible to monitor the impact of PMTCT programmes on peripartum infection; linked screening could identify infected children early for referral into care and treatment programmes.     

Transmission of hepatitis C virus to infants of human immunodeficiency virus-negative intravenous drug-using mothers: rate of infection and assessment of risk factors for transmission

The risk of perinatal transmission of hepatitis C virus (HCV) from a cohort of 95 human immunodeficiency virus (HIV)-negative intravenous drug users (IVDU) is described, 89 of whom were positive for antibodies to HCV (anti-HCV). Infection, defined as the presence of HCV RNA in a serum sample collected from an infant at any time during follow-up, was detected in six of 63 (9.5%) infants born to HCV antibody-positive viraemic mothers. No mother who was HCV RNA negative at delivery transmitted HCV to her infant. Hepatitis C virus antibodies became undetectable in uninfected infants by 15 months, but persisted in all HCV-infected infants throughout follow-up. An abnormal alanine aminotransferase (ALT) level was observed on at least one occasion in all HCV-infected infants and in six occasions in uninfected infants. Two of the six HCV-infected infants became HCV RNA negative during follow-up by 27 and 29 months. Both of these infants had a large ALT elevation (mean peak ALT 398Ul^–1) at around 12 months of age. Analysis of a range of potential risk factors revealed that maternal HCV RNA load was important in predicting transmission, but suggested that other factors play a role in perinatal transmission from mother to child. No difference was found between mothers who transmitted HCV to their infants and those who did not for HCV genotype, duration of drug use, duration of methadone use, methadone dose, history of alcohol abuse, past hepatitis B virus (HBV) infection, mode of delivery, maternal and gestational age, birth weight and incidence of breast-feeding. Mothers who transmitted HCV to their infants had a longer duration between membrane rupture and delivery than the mothers who did not transmit ( P =0.03). HCV RNA was not detected in breast milk and colostrum samples from 38 viraemic mothers, including two who transmitted HCV to their infant.     

Cardiovascular effects of HAART in infants and children of HIV-infected mothers

Over the past decade, the course of human immunodeficiency virus (HIV) infection has been markedly altered by highly active antiretroviral therapy (HAART). As advances in early diagnosis and aggressive therapy, as well as better supportive care, become available to more HIV-infected patients, survival is being prolonged and more patients are experiencing cardiac abnormalities. Cardiovascular manifestations of pediatric HIV infection have especially proven to be an ongoing challenge to practicing physicians, who face cardiac abnormalities ranging from asymptomatic cardiomyopathy to severe heart failure. Antiretroviral therapy has substantially decreased vertical transmission of HIV; however, studies of adults receiving HAART have found increased peripheral and coronary artery disease. Children exposed to this therapy in utero are thus at an increased risk for toxicity and cardiac abnormalities, regardless of their HIV status. Preliminary studies have reported complications including lactic acidosis and mitochondrial toxicity, as well as cardiomyopathy. Further studies are needed to explore the long-term effects and possible toxicities of prophylactic antiretroviral therapy on infants born to HIV-infected mothers.     

Mother–baby dyads enrolled in PMTCT care in western Kenya: characteristics and implications for ART programmes

The objective of the study was to establish the mother–baby pair characteristics that contribute to vertical transmission of HIV and elucidate on remediation. We assessed for factors increasing the odds of HIV transmission in children born to HIV-infected mothers in western Kenya. We used a retrospective study which reviewed routinely collected data of 1 028 mother–baby pairs enrolled in a prevention of mother-to-child transmission (PMTCT) programme in western Kenya from January to December 2015. We compared the transmission rates amongst mothers known to have a positive HIV status before conception (known positives/KPs) versus the transmission amongst those who were newly diagnosed during maternal and child health (MCH) clinic attendance (new positives/NPs). We compared the socio-demographic and clinical characteristics of the mothers using chi square and Kruskal–Wallis tests at 95% confidence interval (CI). We assessed for factors associated with the infants’ HIV status using a logistic regression model. The results revealed that 60% (622) of the mothers were KPs, and that KPs and NPs had mother-to-child transmission (MTCT) rates of 5.5% and 20.7% respectively. Close to 90% of the NP Mothers were at an early HIV clinical stage at enrolment and 40% were enrolled after delivery. The infants of NPs were enrolled at a mean age of 18.3 weeks compared to 6.6 weeks for the infants of the KPs. On adjusted multivariable analysis, child's age at enrolment (AOR = 1.05, 95%CI = 1.036–1.064) and mother's status at conception (AOR = 1.96, 95%CI = 1.042–3.664) were significantly associated with the infant's HIV status. None of the HIV infected infants had received nevirapine prophylaxis. Most of the mothers enrolling into the PMTCT programme have a known HIV-positive status, however, NPs are the largest contributors to continued MTCT.     

Vertical transmission of human immunodeficiency virus is correlated with the absence of high-affinity/avidity maternal antibodies to the gp120 principal neutralizing domain.

Many, but not all, infants born to mothers infected with the human immunodeficiency virus (HIV) are infected in utero. We have now shown that mothers who have high-affinity/avidity antibodies directed toward the principal neutralizing domain (PND) of gp120 are less likely to transmit HIV to their children. An ELISA that preferentially measures the level of the biologically functioning, high-affinity/avidity antibodies against PND is described. In a retrospective study of 15 maternal/neonatal serum samples, the assay correctly identified the 4 uninfected and the 11 HIV-infected infants. Other clinical and laboratory parameters such as p24 antigen, phytohemagglutinin mitogenic index, and absolute surface antigen T4+ cell counts did not accurately predict HIV fetal transmission. In addition to introducing a promising diagnostic tool, this study provides the in vivo evidence that protective antibodies may prevent infection by HIV.     

Mother-to-child transmission of hepatitis C virus detected by nested polymerase chain reaction.

Serum samples from eight pregnant women and their offspring were studied by nested polymerase chain reaction (PCR) for detection of hepatitis C virus (HCV) RNA to evaluate mother-to-child transmission of this virus. The mothers were all infected with human immunodeficiency virus (HIV); none showed symptoms of HCV infection. Anti-HCV antibodies were tested for by recombinant immunoblot assay. HCV viral sequences were found in five of the mothers and four of eight children, three of them at birth. Viremia was persistent in one infant who had chronic transaminase elevation and persistently remained anti-HCV-positive. The other three babies had intermittent viremia; all were asymptomatic and lost anti-HCV antibodies during follow-up. This loss of antibodies was also observed in PCR-negative infants. Thus, these results demonstrate transmission of HCV from mother to child by women coinfected with HCV and HIV. They indicate the usefulness of PCR for direct and early detection of HCV viremia in neonates.     

Neonatal measles immunity in rural Kenya: the influence of HIV and placental malaria infections on placental transfer of antibodies and levels of antibody in maternal and cord serum samples

INTRODUCTION: Young infants are protected from measles infection by maternal measles antibodies. The level of these antibodies at birth depends on the level of antibodies in the mother and the extent of placental transfer. We investigated predictors of levels of measles antibodies in newborns in rural Kenya. METHODS: A total of 747 paired maternal-cord serum samples (91 from human immunodeficiency virus [HIV]-infected and 656 from HIV-uninfected mothers) were tested for measles immunoglobulin G antibodies. Placental malaria infection was determined by biopsy. Data on pregnancy history, gestational age, and anthropometric and socioeconomic status were collected. RESULTS: Infants born to HIV-infected mothers were more likely (odds ratio, 4.6 [95% confidence interval {CI}, 2.2-9.7]) to be seronegative and had 35.1% (95% CI, 9.8%-53.2%) lower levels of measles antibodies than did those born to HIV-uninfected mothers. Preterm delivery, early maternal age, and ethnic group were also associated with reduced levels of measles antibodies. There was little evidence that placental malaria infection was associated with levels of measles antibodies in newborns. CONCLUSION: Our results suggest that maternal HIV infection may reduce levels of measles antibodies in newborns. Low levels of measles antibodies at birth render children susceptible to measles infection at an early age. This is of concern in sub-Saharan African countries, where not only is the prevalence of HIV high, but measles is the cause of much morbidity and mortality.     

Presence of maternal antibodies to human immunodeficiency virus 1 envelope glycoprotein gp120 epitopes correlates with the uninfected status of children born to seropositive mothers.

The present study demonstrates that maternal antibodies to certain epitopes of human immunodeficiency virus 1 (HIV-1) proteins are associated with a defined outcome for at-risk pregnancies of HIV-infected women. An initial retrospective analysis of antibodies to synthetic peptides and recombinant proteins representing env, pol, and gag regions of HIV-1 was carried out. Sera studied were from 33 children who were born to HIV-infected mothers and whose clinical outcome was known at the time of analysis. Sera, collected within the first 6 months of life, of uninfected at-risk children were found to selectively contain maternal antibodies to certain peptides containing epitopes of the HIV envelope glycoprotein gp120. To confirm the predictive role of maternal antibodies to defined HIV-1 epitopes, a prospective analysis was then performed on sera from 21 HIV-seropositive mothers and their infants, whose clinical and immunological status was then followed up for a period of at least 15 months. As expected, antibodies to the same envelope protein peptides were detected almost exclusively in sera from mothers of uninfected children. Our data suggest that antibodies against select epitopes of HIV envelope protein gp120 might play an important role in preventing mother-to-child transmission of HIV-1 infection. Accordingly, site-directed serology might be used to predict the outcome of an at-risk pregnancy of an HIV-infected woman.     

Early diagnosis of vertical HIV infection in infants by rapid detection of immune complex-dissociated HIV p24 antigen

Conventional HIV antibody detection was problematic for diagnosis of HIV infection in young infants < 18 months of age who were born to HIV-infected mothers. The HIV p24 antigen (Ag) is mainly bound to the antibody as an immune complex which causes underdetection by conventional methods. Attempts were made to dissociate these immune complexes to release free p24 Ag for detection. The current study's objective was to evaluate the rapid assays for detection of immune complex-dissociated p24 Ag (ICD p24 Ag) for early identification of HIV-infected infants as compared to the detection of HIV RNA by polymerase chain reaction (PCR) assay. The ICD was performed by acid dissociation and heat-denatured dissociation, and then the released ICD p24 Ag were detected. Tested were 41 HIV-infected children who acquired the infection perinatally and who had positive PCR and 30 HIV noninfected children with negative PCR. The overall sensitivity of the ICD p24 Ag detection after acid- and heat-denatured dissociation in the infected children was 85.4% and 87.8%, respectively, compared to 34.2% of p24 Ag without pretreatment for dissociation of the serum samples. The specificity of nonimmune complex dissociation and both methods of immune complex dissociation test were 100%. The sensitivity of ICD-p24 Ag test using these two methods showed excellent agreement (K = 0.893). Besides the relatively high sensitivity and specificity of the ICD p24 Ag test, its advantages include simplicity, rapidity, and relatively low cost--indicating ICD p24 Ag detection as a promising method for early diagnosis of vertical HIV infection in infants.     

The efficacy and tolerability of combination antiretroviral therapy in pregnancy: infant and maternal outcome

Antiretroviral therapy (ART) and Caesarean section (CS) delivery significantly reduce the risk of vertically transmitted HIV infection. Attention must focus on determining the optimal management strategy for HIV-positive pregnancies. Guidelines must reflect not only the activity and tolerability of combination ART in pregnancy for mother and infant and the potential short and long-term infant toxicity, but also whether surgical delivery can confer an added benefit if combination ART had reduced plasma viraemia to undetectable levels. To aid the development of management strategies for the Republic of Ireland, a retrospective detailed review of all HIV-positive pregnancies since the introduction of combination ART was undertaken. Since 1997 there have been 25 deliveries to 24 women. Combination ART reduced plasma viraemia to undetectable levels in 76% mothers at delivery. The CS rate was 28% and no unanticipated infant toxicity was encountered. To date no infant has proven infected. Three infants have seroreverted and 24 of 26 infants have had at least 2 negative HIV ribonucleic acid (RNA) and polymerase chain reaction (PCR) tests. Two infants are less than one month old. In this study, the CS rate of 28% is below that reported from many centres yet no vertical transmission was found. Given the efficacy of ART in reducing plasma viraemia, the additional benefit of CS for these women is questionable.     

中国部分地区艾滋病病毒1型母婴传播回顾性追踪调查

目的 了解中国艾滋病病毒1型(HIV-1)母婴传播的现状,特别是母婴传播的发生率和影响因素,为进一步开展预防阻断工作提供背景资料。方法 以地方卫生防疫和医疗机构的哨点监测、产前筛查、日常检测和门诊中发现的HIV-1阳性孕产妇为对象,对其所生子女进行追踪调查和检测。结果 对来自云南、河南、新疆等10个省(自治区、直辖市)的87例HIV-1阳性母亲所生的94名儿童进行追踪,最后追踪到75例母亲及其所生的80名儿童,HIV-1母婴传播发生率为35.0％(28/80)。而河南省的母婴传播率为41.7％(10/24),云南省和新疆维吾尔自治区分别为33.3％(11/33)和27.3％(3/11)。对相关影响因素的分析发现,母亲的感染途径、生产胎次和喂养方式对HIV-1母婴传播有一定的影响作用,其中输血传播、初产和母乳喂养是高危因素。相应的母婴传播率分别为45.5％、39.2％和36.2％,而性传播、多胎生产及人工喂养分别为32.1％、25.9％和22.2％,但差异无显著统计学意义。结论 该研究表明,中国HIV-1母婴传播率与亚非发展中国家相似,而高于西方发达国家。对相关的高危因素(如孕妇的感染途径,特别是输血传播)有必要作进一步地研究。     

Early growth of infants of HIV-infected and uninfected Zambian women

OBJECTIVE: Parental HIV infection may affect even those exposed children who remain uninfected. We investigated early growth, an indicator of overall health, of infants born to Zambian mothers recruited for a study of breastfeeding and postpartum health. METHODS: HIV-infected and uninfected women in Lusaka were followed regularly from late pregnancy to 16 weeks postpartum. Infant weight and length were measured at birth, 6 and 16 weeks. Infant HIV status could not be specifically determined in this cohort so comparisons were between all infants of HIV-uninfected mothers (n = 184) and those infants of HIV-infected mothers who were known to be alive and showed no clinical evidence of HIV infection at age 2-4 years (n = 85). RESULTS: Most infants were exclusively or predominantly breastfed until 16 weeks. At all time points infants of HIV-infected mothers tended to have lower weight and length standard deviation (Z) scores (significant for weight at 6 weeks; P = 0.04), even after adjustment for their lower gestational age at birth, compared with infants of uninfected mothers. In multivariate analyses the major factors affecting weight or length at 6 or 16 weeks of age were birth weight or length, and maternal subclinical mastitis, primiparity and weight during pregnancy. CONCLUSIONS: Early growth of infants of HIV-infected mothers is less than that of uninfected mothers, in part associated with subclinical mastitis, and this effect cannot be overcome with intensive support of mothers to follow international recommendations regarding exclusive breastfeeding.     

Influence of hepatitis G virus (GB virus C) on the prognosis of HIV-infected women

This study was undertaken to evaluate the prevalence of GB virus C (GBV-C) viraemia and anti-E2 antibody, and to assess the effect of co-infection with GBV-C and HIV during a 10-year follow-up of a cohort of 248 HIV-infected women. Laboratory variables (mean and median CD4 counts, and HIV and GBV-C viral loads) and clinical parameters were investigated. At baseline, 115 women had past exposure to GBV-C: 57 (23%) were GBV-C RNA positive and 58 (23%) were anti-E2 positive. There was no statistical difference between the groups (GBV-C RNA + /anti-E2 - , GBV-C RNA - /anti-E2 + and GBV-C RNA - /anti-E2 - ) regarding baseline CD4 counts or HIV viral loads (P = 0.360 and 0.713, respectively). Relative risk of death for the GBV-C RNA + /anti-E2 - group was 63% lower than that for the GBV-C RNA - /anti-E2 - group. Multivariate analysis demonstrated that only HIV loads ≥ 100,000 copies/mL and AIDS-defining illness during follow-up were associated with shorter survival after AIDS development. It is likely that antiretroviral therapy (ART) use in our cohort blurred a putative protective effect related to the presence of GBV-C RNA.     

Effect of early and late GB virus C viraemia on survival of HIV-infected individuals: a meta-analysis

OBJECTIVES: To conduct a meta-analysis to synthesize the evidence regarding the effect of co-infection with GB virus C (GBV-C) on survival of HIV-infected individuals, and to estimate the effect. METHODS: A Bayesian meta-analysis was conducted to synthesize evidence from eligible studies. Prospective survival studies of HIV-1-infected individuals, with outcome defined as time from baseline to all-cause death, were included and classified by whether GBV-C status was determined in early or late HIV disease. The primary measure was the hazard ratio (HR) of death for HIV-infected individuals with GBV-C infection versus those without GBV-C infection. RESULTS: Eleven studies from eight publications met the inclusion criteria. For studies with GBV-C status measured 2 years or less after HIV seroconversion (912 subjects), the combined HR was 0.88 [95% credible interval (CI) 0.30, 1.50]. For studies with GBV-C status measured more than 2 years after HIV seroconversion (1294 subjects), the combined HR was 0.41 (95% CI 0.23, 0.69). CONCLUSIONS: No conclusive evidence was found of an association between survival and GBV-C infection early in HIV disease. However, when GBV-C infection was present later in HIV disease, a significant reduction in the hazard for mortality was observed for those with co-infection. Potential explanations for this difference include a non-proportional benefit of GBV-C over time, possibly related to clearance of GBV-C infection early in HIV disease. The timing of GBV-C infection appears to account for the contradictory results of studies on the effect of GBV-C coinfection on survival of HIV-infected people.     

Effect of placental malaria and HIV infection on the antibody responses to Plasmodium falciparum in infants

BACKGROUND: Placental malaria (PM) and maternal infection with human immunodeficiency virus (HIV) type 1 have been shown to affect infant morbidity and immune responses to Plasmodium falciparum. We studied the effects of PM and HIV infection on the antimalarial antibody responses and morbidity outcomes of infants throughout the first year of life. METHODS: A total of 411 Kenyan infants who were born to mothers who were singly or dually infected with PM and/or HIV had their levels of immunoglobulin G antibody to 6 P. falciparum antigens/epitopes (apical membrane antigen-1, erythrocyte-binding antigen-175; liver-stage antigen-1 [LSA-1], circumsporozoite protein [CSP], merozoite surface protein-2, and rhoptry-associated protein-1 [RAP-1]) and to tetanus toxoid (TT) tested using enzyme-linked immunosorbent assay. RESULTS: PM had little effect on the antibody responses of infants, whereas maternal HIV infection resulted in decreased levels of antibody to LSA-1, CSP, and RAP-1 epitopes at birth, compared with the absence of PM and maternal HIV infection (P = .0063). Levels of antibodies to TT were significantly reduced in infants born to mothers coinfected with HIV and PM, compared with the levels noted in infants born to HIV-negative mothers (P = .0003). In HIV-infected infants, levels of antibody to TT were reduced, but levels of antibody to malarial antigens were not. Antimalarial antibody levels were positively associated with malaria-related morbidity outcomes. CONCLUSION: Infant HIV infection and maternal coinfection with HIV and PM negatively influence antibody responses to TT, but not those to malarial antigens, in infants. Antimalarial antibodies rarely showed protective associations with morbidity in infants and were more often a marker for malaria exposure and risk of infection.