Effect of Malaria and Malaria Chemoprevention Regimens in Pregnancy and Childhood on Neurodevelopmental and Behavioral Outcomes in Children at 12, 24, and 36 Months: A Randomized Clinical Trial.

BACKGROUND: Malaria in pregnancy has been associated with worse cognitive outcomes in children, but its association with behavioral outcomes and the effectiveness of malaria chemoprevention on child neurodevelopment are not well characterized. METHODS: To determine if more effective malaria chemoprevention in mothers and their children results in better neurodevelopment, 305 pregnant women were randomly assigned to 3 doses of sulfadoxine-pyrimethamine, 3 doses of dihydroartemisinin-piperaquine (DP), or monthly DP during pregnancy, and their 293 children were assigned to DP every 3 months or monthly DP from 2 to 24 months of age. Cognition, language, and motor function were assessed at 12, 24. and 36 months of age, and attention, memory, behavior, and executive function were assessed at 24 and 36 months of age. RESULTS: Children of mothers with versus without malaria in pregnancy had worse scores on cognitive, behavioral, and executive function outcomes at 24 months. Clinical malaria in children within the first 12 months was similarly associated with poorer scores in behavior and executive function at 24 months, language at 24 and 36 months, and motor function scores at 36 months. However, more effective malaria chemoprevention in the mothers and children was not associated with better outcomes. CONCLUSIONS: Malaria in pregnancy was associated with worse cognitive, behavioral, and executive function scores in affected children, but more effective malaria chemoprevention measures did not result in better outcomes. Malaria chemoprevention prior to and early in gestation and with even higher efficacy in mothers and children may be required to prevent neurodevelopmental impairment in children. Clinical Trials Registration. NCT02557425.

In Utero Activation of Natural Killer Cells in Congenital Cytomegalovirus Infection.

BACKGROUND: Congenital cytomegalovirus (CMV) infection is the most common infectious cause of birth defects and neurological damage in newborns. Despite a well-established role for natural killer (NK) cells in control of CMV infection in older children and adults, it remains unknown whether fetal NK cells can sense and respond to CMV infection acquired in utero. METHODS: Here, we investigate the impact of congenital CMV infection on the neonatal NK-cell repertoire by assessing the frequency, phenotype, and functional profile of NK cells in cord blood samples from newborns with congenital CMV and from uninfected controls enrolled in a birth cohort of Ugandan mothers and infants. RESULTS: We find that neonatal NK cells from congenitally CMV infected newborns show increased expression of cytotoxic mediators, signs of maturation and activation, and an expansion of mature CD56- NK cells, an NK-cell subset associated with chronic viral infections in adults. Activation was particularly prominent in NK cell subsets expressing the Fcγ receptor CD16, indicating a role for antibody-mediated immunity against CMV in utero. CONCLUSIONS: These findings demonstrate that NK cells can be activated in utero and suggest that NK cells may be an important component of the fetal and infant immune response against CMV. CLINICAL TRIALS REGISTRATION: NCT02793622.

Peripheral Plasmodium falciparum Infection in Early Pregnancy Is Associated With Increased Maternal Microchimerism in the Offspring.

BACKGROUND: Placental malaria has been associated with increased cord blood maternal microchimerism (MMc), which in turn may affect susceptibility to malaria in the offspring. We sought to determine the impact of maternal peripheral Plasmodium falciparum parasitemia during pregnancy on MMc and to determine whether maternal cells expand during primary parasitemia in the offspring. METHODS: We conducted a nested cohort study of maternal-infant pairs from a prior pregnancy malaria chemoprevention study. Maternal microchimerism was measured by quantitative polymerase chain reaction targeting a maternal-specific marker in genomic DNA from cord blood, first P falciparum parasitemia, and preparasitemia. Logistic and negative binomial regression were used to assess the impact of maternal peripheral parasitemia, symptomatic malaria, and placental malaria on cord blood MMc. Generalized estimating equations were used to assess predictors of MMc during infancy. RESULTS: Early maternal parasitemia was associated with increased detection of cord blood MMc (adjusted odds ratio = 3.91, P = .03), whereas late parasitemia, symptomatic malaria, and placental malaria were not. The first parasitemia episode in the infant was not associated with increased MMc relative to preparasitemia. CONCLUSIONS: Maternal parasitemia early in pregnancy may increase the amount of MMc acquired by the fetus. Future work should investigate the impact of this MMc on immune responses in the offspring.

Generation of a malaria negative Ugandan birth weight standard for the diagnosis of small for gestational age.

OBJECTIVE: Placental malaria is a known risk factor for small for gestational age (SGA) neonates. However, currently utilized international and African birthweight standards have not controlled for placental malaria and/or lack obstetrical ultrasound dating. We developed a neonatal birthweight standard based on obstetrically dated pregnancies that excluded individuals with clinical malaria, asymptomatic parasitemia, and placental malaria infection. We hypothesized that current curves underestimate true ideal birthweight and the prevalence of SGA. STUDY DESIGN: Participants were pooled from two double-blind randomized control trials of intermittent preventive therapy during pregnancy in Uganda. HIV-negative women without comorbidities were enrolled from 12-20 weeks gestation. Gestational age was confirmed by ultrasound dating. Women were followed through pregnancy and delivery for clinical malaria, asymptomatic parasitemia, and placental malaria. Women without malaria, asymptomatic parasitemia, or placental malaria formed the malaria negative cohort and generated the Ugandan birthweight standard. The Ugandan standard was then used to estimate the prevalence of SGA neonates in the malaria positive cohort. These findings were compared to international (Williams, World Health Organization (WHO), and INTERGROWTH-21st) and regional standards (Tanzanian and Malawi). RESULTS: 926 women had complete delivery data; 393 (42.4%) met criteria for the malaria negative cohort and 533 (57.6%) were malaria positive. The Ugandan standard diagnosed SGA in 17.1% of malaria positive neonates; similar to the INTERGROWTH-21st and Schmiegelow curves. The WHO curve diagnosed SGA in significantly more neonates (32.1%, p = <0.001), and the Malawi curve diagnosed SGA in significantly fewer neonates (8.3%, p <0.001). CONCLUSION: Exclusion of women with subclinical placental malaria in malaria-endemic areas created birth weight norms at higher values and increased the detection of SGA. Birth weight standards that fail to account for endemic illness may underestimate the true growth potential of healthy neonates.

The impact of gravidity, symptomatology and timing of infection on placental malaria.

BACKGROUND: Placental malaria is associated with increased risk of adverse perinatal outcomes. While primigravidity has been reported as a risk factor for placental malaria, little is known regarding the relationship between gravidity, symptomatology and timing of Plasmodium falciparum infection and the development of placental malaria. METHODS: The aim of this study was to investigate the relationship between the development of placental malaria and gravidity, timing of infection, and presence of symptoms. This is a secondary analysis of data from a double-blind randomized control trial of intermittent preventive therapy during pregnancy in Uganda. Women were enrolled from 12 to 20 weeks gestation and followed through delivery. Exposure to malaria parasites was defined as symptomatic (fever with positive blood smear) or asymptomatic (based on molecular detection of parasitaemia done routinely every 4 weeks). The primary outcome was placental malaria diagnosed by histopathology, placental blood smear, and/or placental blood loop-mediated isothermal amplification. Multivariate analyses were performed using logistic regression models. Subgroup analysis was performed based on the presence of symptomatic malaria, gravidity, and timing of infection. RESULTS: Of the 228 patients with documented maternal infection with malaria parasites during pregnancy, 101 (44.3%) had placental malaria. Primigravidity was strongly associated with placental malaria (aOR 8.90, 95% CI 4.34-18.2, p < 0.001), and each episode of malaria was associated with over a twofold increase in placental malaria (aOR 2.35, 95% CI 1.69-3.26, p < 0.001). Among multigravid women, the odds of placental malaria increased by 14% with each advancing week of gestation at first documented infection (aOR 1.14, 95% CI 1.02-1.27, p = 0.02). When stratified by the presence of symptoms, primigravidity was only associated with placental malaria in asymptomatic women, who had a 12-fold increase in the odds of placental malaria (aOR 12.19, 95% CI 5.23-28.43, p < 0.001). CONCLUSIONS: Total number of P. falciparum infections in pregnancy is a significant predictor of placental malaria. The importance of timing of infection on the development of placental malaria varies based on gravidity. In primigravidas, earlier asymptomatic infections were more frequently identified in those with placental malaria, whereas in multigravidas, parasitaemias detected later in gestation were associated with placental malaria. Earlier initiation of an effective intermittent preventive therapy may help to prevent placental malaria and improve birth outcomes, particularly in primigravid women.

Intermittent preventive treatment with dihydroartemisinin-piperaquine and risk of malaria following cessation in young Ugandan children: a double-blind, randomised, controlled trial.

BACKGROUND: Intermittent preventive treatment (IPT) of malaria with dihydroartemisinin-piperaquine is a promising strategy for malaria prevention in young African children. However, the optimal dosing strategy is unclear and conflicting evidence exists regarding the risk of malaria after cessation of chemoprevention. We aimed to compare two dosing strategies of IPT with dihydroartemisinin-piperaquine in young Ugandan children, and to evaluate the risk of malaria after cessation of IPT. METHODS: In this double-blind, randomised controlled phase 2 trial, women and their unborn children were recruited at Tororo District Hospital (Tororo, Uganda). Eligible participants were HIV-negative women aged 16 years or older with a viable pregnancy (gestational age 12-20 weeks). Women and their unborn children were randomly assigned (1:1:1:1) to one of four treatment groups, all receiving dihydroartemisinin-piperaquine, on the basis of the IPT intervention received by the woman during pregnancy: women every 8 weeks, children every 4 weeks; women every 4 weeks, children every 4 weeks; women every 8 weeks, children every 12 weeks; and women every 4 weeks, children every 12 weeks. Block randomisation was done by an independent investigator using a computer-generated randomisation list (permuted block sizes of six and 12). We analysed children on the basis of their random assignment to receive dihydroartemisinin-piperaquine (20 mg/160 mg tablets) once daily for 3 consecutive days every 4 weeks or 12 weeks. Children received study drugs from age 8 weeks to 24 months and were followed-up to age 36 months. Participants and investigators were masked to treatment allocation. The primary outcome was the incidence of symptomatic malaria during the intervention and following cessation of the intervention, adjusted for potential confounders. The primary outcome and safety were assessed in the modified intention-to-treat population, which included all children who reached 8 weeks of age and received at least one dose of study drug. This trial is registered with ClinicalTrials.gov, number NCT02163447. FINDINGS: Between Oct 21, 2014, and May 18, 2015, 191 children were born, of whom 183 reached 8 weeks of age and received at least one dose of study drug and thus were included in the primary analysis (96 children in the 4-week group and 87 in the 12-week group). During the intervention, the incidence of symptomatic malaria was significantly lower among children treated every 4 weeks than children treated every 12 weeks; three episodes occurred among children treated every 4 weeks (incidence 0·018 episodes per person-year) compared with 61 episodes among children treated every 12 weeks (incidence 0·39 episodes per person-year; adjusted incidence rate ratio [aIRR] 0·041, 95% CI 0·012-0·150, p<0·0001). After cessation of IPT, children who had previously received dihydroartemisinin-piperaquine every 4 weeks had a lower incidence of symptomatic malaria than children who were treated every 12 weeks; 62 episodes occurred among children previously treated every 4 weeks (incidence 0·73 episodes per person-year) compared with 83 episodes among children treated every 12 weeks (incidence 1·1 episodes per person-year; aIRR 0·62, 0·40-0·95, p=0·028). In the 4-week group, 94 (98%) of 96 children had adverse events versus 87 (100%) of 87 children in the 12-week group. The most commonly reported adverse event was cough in both treatment groups (94 [98%] in the 4-week group vs 87 [100%] in the 12-week group). 16 children had severe adverse events (seven [7%] children in the 4-week group vs nine [10%] children in the 12-week group). No severe adverse events were thought to be related to study drug administration. One death occurred during the intervention (age 8 weeks to 24 months), which was due to respiratory failure unrelated to malaria. INTERPRETATION: IPT with dihydroartemisinin-piperaquine given every 4 weeks was superior to treatment every 12 weeks for the prevention of malaria during childhood, and this protection was extended for up to 1 year after cessation of IPT. FUNDING: Eunice Kennedy Shriver National Institute of Child Health and Human Development.

Case Report: Birth Outcome and Neurodevelopment in Placental Malaria Discordant Twins.

Maternal infection during pregnancy can have lasting effects on neurodevelopment, but the impact of malaria in pregnancy on child neurodevelopment is unknown. We present a case of a 24-year-old gravida three woman enrolled at 14 weeks 6 days of gestation in a clinical trial evaluating malaria prevention strategies in pregnancy. She had two blood samples test positive for Plasmodium falciparum using loop-mediated isothermal amplification before 20 weeks of gestation. At 31 weeks 4 days of gestation, the woman presented with preterm premature rupture of membranes, and the twins were delivered by cesarean section. Twin A was 1,920 g and Twin B was 1,320 g. Both placentas tested negative for malaria by microscopy, but the placenta of Twin B had evidence of past malaria by histology. The twins' development was assessed using the Bayley Scales of Infant and Toddler Development-Third Edition. At 1 year chronologic age, Twin B had lower scores across all domains (composite scores: cognitive, Twin A [100], Twin B [70]; motor, Twin A [88], Twin B [73]; language, Twin A [109], Twin B [86]). This effect persisted at 2 years chronologic age (composite scores: cognitive, Twin A [80], Twin B [60]; motor, Twin A [76], Twin B [67]; language, Twin A [77], Twin B [59]). Infant health was similar over the first 2 years of life. We report differences in neurodevelopmental outcomes in placental malaria-discordant dizygotic twins. Additional research is needed to evaluate the impact of placental malaria on neurodevelopmental complications. Trial registration number: ClinicalTrials.gov number, NCT02163447. Registered: June 2014, https://clinicaltrials.gov/ct2/show/NCT02163447.

Dihydroartemisinin-piperaquine for intermittent preventive treatment of malaria during pregnancy and risk of malaria in early childhood: A randomized controlled trial.

BACKGROUND: Intermittent preventive treatment of malaria in pregnancy (IPTp) with dihydroartemisinin-piperaquine (IPTp-DP) has been shown to reduce the burden of malaria during pregnancy compared to sulfadoxine-pyrimethamine (IPTp-SP). However, limited data exist on how IPTp regimens impact malaria risk during infancy. We conducted a double-blinded randomized controlled trial (RCT) to test the hypothesis that children born to mothers given IPTp-DP would have a lower incidence of malaria during infancy compared to children born to mothers who received IPTp-SP. METHODS AND FINDINGS: We compared malaria metrics among children in Tororo, Uganda, born to women randomized to IPTp-SP given every 8 weeks (SP8w, n = 100), IPTp-DP every 8 weeks (DP8w, n = 44), or IPTp-DP every 4 weeks (DP4w, n = 47). After birth, children were given chemoprevention with DP every 12 weeks from 8 weeks to 2 years of age. The primary outcome was incidence of malaria during the first 2 years of life. Secondary outcomes included time to malaria from birth and time to parasitemia following each dose of DP given during infancy. Results are reported after adjustment for clustering (twin gestation) and potential confounders (maternal age, gravidity, and maternal parasitemia status at enrolment).The study took place between June 2014 and May 2017. Compared to children whose mothers were randomized to IPTp-SP8w (0.24 episodes per person year [PPY]), the incidence of malaria was higher in children born to mothers who received IPTp-DP4w (0.42 episodes PPY, adjusted incidence rate ratio [aIRR] 1.92; 95% CI 1.00-3.65, p = 0.049) and nonsignificantly higher in children born to mothers who received IPT-DP8w (0.30 episodes PPY, aIRR 1.44; 95% CI 0.68-3.05, p = 0.34). However, these associations were modified by infant sex. Female children whose mothers were randomized to IPTp-DP4w had an apparently 4-fold higher incidence of malaria compared to female children whose mothers were randomized to IPTp-SP8w (0.65 versus 0.20 episodes PPY, aIRR 4.39, 95% CI 1.87-10.3, p = 0.001), but no significant association was observed in male children (0.20 versus 0.28 episodes PPY, aIRR 0.66, 95% CI 0.25-1.75, p = 0.42). Nonsignificant increases in malaria incidence were observed among female, but not male, children born to mothers who received DP8w versus SP8w. In exploratory analyses, levels of malaria-specific antibodies in cord blood were similar between IPTp groups and sex. However, female children whose mothers were randomized to IPTp-DP4w had lower mean piperaquine (PQ) levels during infancy compared to female children whose mothers received IPTp-SP8w (coef 0.81, 95% CI 0.65-1.00, p = 0.048) and male children whose mothers received IPTp-DP4w (coef 0.72, 95% CI 0.57-0.91, p = 0.006). There were no significant sex-specific differences in PQ levels among children whose mothers were randomized to IPTp-SP8w or IPTp-DP8w. The main limitations were small sample size and childhood provision of DP every 12 weeks in infancy. CONCLUSIONS: Contrary to our hypothesis, preventing malaria in pregnancy with IPTp-DP in the context of chemoprevention with DP during infancy does not lead to a reduced incidence of malaria in childhood; in this setting, it may be associated with an increased incidence of malaria in females. Future studies are needed to better understand the biological mechanisms of in utero drug exposure on drug metabolism and how this may affect the dosing of antimalarial drugs for treatment and prevention during infancy. TRIAL REGISTRATION: ClinicalTrials.gov number NCT02163447.

Intermittent Preventive Treatment for Malaria in Pregnancy: Optimization of Target Concentrations of Dihydroartemisinin-Piperaquine.

Background: Dihydroartemisinin-piperaquine (DHA-PQ) is highly efficacious as intermittent preventive therapy for malaria during pregnancy (IPTp). Determining associations between piperaquine (PQ) exposure, malaria risk, and adverse birth outcomes informs optimal dosing strategies. Methods: Human immunodeficiency virus-uninfected pregnant women (n = 300) were enrolled in a placebo-controlled trial of IPTp at 12-20 weeks' gestation and randomized to sulfadoxine-pyrimethamine every 8 weeks, DHA-PQ every 8 weeks, or DHA-PQ every 4 weeks during pregnancy. Pharmacokinetic sampling for PQ was performed every 4 weeks, and an intensive pharmacokinetic substudy was performed in 30 women at 28 weeks' gestation. Concentration-effect relationships were assessed between exposure to PQ; the prevalence of Plasmodium falciparum infection during pregnancy; outcomes at delivery including placental malaria, low birth weight, and preterm birth; and risks for toxicity. Simulations of new dosing scenarios were performed. Results: Model-defined PQ target venous plasma concentrations of 13.9 ng/mL provided 99% protection from P. falciparum infection during pregnancy. Each 10-day increase in time above target PQ concentrations was associated with reduced odds of placental parasitemia, preterm birth, and low birth weight, though increases in PQ concentrations were associated with QT interval prolongation. Modeling suggests that daily or weekly administration of lower dosages of PQ, compared to standard dosing, will maintain PQ trough levels above target concentrations with reduced PQ peak levels, potentially limiting toxicity. Conclusions: The protective efficacy of IPTp with DHA-PQ was strongly associated with higher drug exposure. Studies of the efficacy and safety of alternative DHA-PQ IPTp dosing strategies are warranted. Clinical Trials Registration: NCT02163447.

Relationships between infection with Plasmodium falciparum during pregnancy, measures of placental malaria, and adverse birth outcomes.

BACKGROUND: Malaria in pregnancy has been associated with maternal morbidity, placental malaria, and adverse birth outcomes. However, data are limited on the relationships between longitudinal measures of malaria during pregnancy, measures of placental malaria, and birth outcomes. METHODS: This is a nested observational study of data from a randomized controlled trial of intermittent preventive therapy during pregnancy among 282 participants with assessment of placental malaria and delivery outcomes. HIV-uninfected pregnant women were enrolled at 12-20 weeks of gestation. Symptomatic malaria during pregnancy was measured using passive surveillance and monthly detection of asymptomatic parasitaemia using loop-mediated isothermal amplification (LAMP). Placental malaria was defined as either the presence of parasites in placental blood by microscopy, detection of parasites in placental blood by LAMP, or histopathologic evidence of parasites or pigment. Adverse birth outcomes assessed included low birth weight (LBW), preterm birth (PTB), and small for gestational age (SGA) infants. RESULTS: The 282 women were divided into three groups representing increasing malaria burden during pregnancy. Fifty-two (18.4%) had no episodes of symptomatic malaria or asymptomatic parasitaemia during the pregnancy, 157 (55.7%) had low malaria burden (0-1 episodes of symptomatic malaria and < 50% of samples LAMP+), and 73 (25.9%) had high malaria burden during pregnancy (≥ 2 episodes of symptomatic malaria or ≥ 50% of samples LAMP+). Women with high malaria burden had increased risks of placental malaria by blood microscopy and LAMP [aRR 14.2 (1.80-111.6) and 4.06 (1.73-9.51), respectively], compared to the other two groups combined. Compared with women with no malaria exposure during pregnancy, the risk of placental malaria by histopathology was higher among low and high burden groups [aRR = 3.27 (1.32-8.12) and aRR = 7.07 (2.84-17.6), respectively]. Detection of placental parasites by any method was significantly associated with PTB [aRR 5.64 (1.46-21.8)], and with a trend towards increased risk for LBW and SGA irrespective of the level of malaria burden during pregnancy. CONCLUSION: Higher malaria burden during pregnancy was associated with placental malaria and together with the detection of parasites in the placenta were associated with increased risk for adverse birth outcomes. Trial Registration Current Controlled Trials Identifier NCT02163447.

Malaria burden in a birth cohort of HIV-exposed uninfected Ugandan infants living in a high malaria transmission setting.

BACKGROUND: HIV-exposed, uninfected (HEU) infants suffer high morbidity and mortality in the first year of life compared to HIV-unexposed, uninfected (HUU) infants, but accurate data on the contribution of malaria are limited. METHODS: The incidence of febrile illnesses and malaria were evaluated in a birth cohort of HEU infants. Infants were prescribed daily trimethoprim-sulfamethoxazole (TS) prophylaxis from 6 weeks of age until exclusion of HIV-infection after cessation of breastfeeding. Infants were followed for all illnesses using passive surveillance and routine blood smears were done monthly. Malaria was diagnosed as a positive blood smear plus fever. Placental malaria was determined by histopathology, placental blood smear and PCR. Risk factors for time to first episode of malaria were assessed using a Cox proportional hazards model. Malaria incidence among HEU infants aged 6-12 months was compared to that in other cohorts of HEU and HUU infants from the same region. RESULTS: Among 361 HEU infants enrolled, 248 completed 12 months of follow-up resulting in 1562 episodes of febrile illness and 253 episodes of malaria after 305 person-years of follow-up. The incidence of febrile illness was 5.12 episodes per person-year (PPY), ranging from 4.13 episodes PPY in the first 4 months of life to 5.71 episodes PPY between 5 and 12 months of age. The overall malaria incidence was 0.83 episodes per person-year (PPY), increasing from 0.03 episodes PPY in the first 2 months of life to 2.00 episodes PPY between 11 and 12 months of age. There were no episodes of complicated malaria. The prevalence of asymptomatic parasitaemia was 1.2 % (19 of 1568 routine smears positive). Infants born to mothers with parasites detected from placental blood smears were at higher risk of malaria (hazard ratio = 4.51, P < 0.001). HEU infants in this study had a 2.4- to 3.5-fold lower incidence of malaria compared to HUU infants in other cohort studies from the same area. CONCLUSION: The burden of malaria in this birth cohort of HEU infants living in a high-transmission setting and taking daily TS prophylaxis was relatively low. Alternative etiologies of fever should be considered in HEU-infants taking daily TS prophylaxis who present with fever. Trial Registration NCT00993031, registered 8 October, 2009.

Reductions in malaria in pregnancy and adverse birth outcomes following indoor residual spraying of insecticide in Uganda.

BACKGROUND: Indoor residual spraying of insecticide (IRS) is a key intervention for reducing the burden of malaria in Africa. However, data on the impact of IRS on malaria in pregnancy and birth outcomes is limited. METHODS: An observational study was conducted within a trial of intermittent preventive therapy during pregnancy in Tororo, Uganda. Women were enrolled at 12-20 weeks of gestation between June and October 2014, provided with insecticide-treated bed nets, and followed through delivery. From December 2014 to February 2015, carbamate-containing IRS was implemented in Tororo district for the first time. Exact spray dates were collected for each household. The exposure of interest was the proportion of time during a woman's pregnancy under protection of IRS, with three categories of protection defined: no IRS protection, >0-20 % IRS protection, and 20-43 % IRS protection. Outcomes assessed included malaria incidence and parasite prevalence during pregnancy, placental malaria, low birth weight (LBW), pre-term delivery, and fetal/neonatal deaths. RESULTS: Of 289 women followed, 134 had no IRS protection during pregnancy, 90 had >0-20 % IRS protection, and 65 had >20-43 % protection. During pregnancy, malaria incidence (0.49 vs 0.10 episodes ppy, P = 0.02) and parasite prevalence (20.0 vs 8.9 %, P < 0.001) were both significantly lower after IRS. At the time of delivery, the prevalence of placental parasitaemia was significantly higher in women with no IRS protection (16.8 %) compared to women with 0-20 % (1.1 %, P = 0.001) or >20-43 % IRS protection (1.6 %, P = 0.006). Compared to women with no IRS protection, those with >20-43 % IRS protection had a lower risk of LBW (20.9 vs 3.1 %, P = 0.002), pre-term birth (17.2 vs 1.5 %, P = 0.006), and fetal/neonatal deaths (7.5 vs 0 %, P = 0.03). CONCLUSION: In this setting, IRS was temporally associated with lower malaria parasite prevalence during pregnancy and at delivery, and improved birth outcomes. IRS may represent an important tool for combating malaria in pregnancy and for improving birth outcomes in malaria-endemic settings. Trial Registration Current Controlled Trials Identifier NCT02163447.

B cell sub-types following acute malaria and associations with clinical immunity.

BACKGROUND: Repeated exposure to Plasmodium falciparum is associated with perturbations in B cell sub-set homeostasis, including expansion atypical memory B cells. However, B cell perturbations immediately following acute malaria infection have been poorly characterized, especially with regard to their relationship with immunity to malaria. METHODS: To better understand the kinetics of B cell sub-sets following malaria, the proportions of six B cell sub-sets were assessed at five time points following acute malaria in four to 5 years old children living in a high transmission region of Uganda. B cell sub-set kinetics were compared with measures of clinical immunity to malaria-lower parasite density at the time of malaria diagnosis and recent asymptomatic parasitaemia. RESULTS: Atypical memory B cell and transitional B cell proportions increased following malaria. In contrast, plasmablast proportions were highest at the time of malaria diagnosis and rapidly declined following treatment. Increased proportions of atypical memory B cells were associated with greater immunity to malaria, whereas increased proportions of transitional B cells were associated with evidence of less immunity to malaria. CONCLUSIONS: These findings highlight the dynamic changes in multiple B cell sub-sets following acute, uncomplicated malaria, and how these sub-sets are associated with developing immunity to malaria.

Dihydroartemisinin-Piperaquine for the Prevention of Malaria in Pregnancy.

BACKGROUND: Intermittent treatment with sulfadoxine-pyrimethamine is widely recommended for the prevention of malaria in pregnant women in Africa. However, with the spread of resistance to sulfadoxine-pyrimethamine, new interventions are needed. METHODS: We conducted a double-blind, randomized, controlled trial involving 300 human immunodeficiency virus (HIV)-uninfected pregnant adolescents or women in Uganda, where sulfadoxine-pyrimethamine resistance is widespread. We randomly assigned participants to a sulfadoxine-pyrimethamine regimen (106 participants), a three-dose dihydroartemisinin-piperaquine regimen (94 participants), or a monthly dihydroartemisinin-piperaquine regimen (100 participants). The primary outcome was the prevalence of histopathologically confirmed placental malaria. RESULTS: The prevalence of histopathologically confirmed placental malaria was significantly higher in the sulfadoxine-pyrimethamine group (50.0%) than in the three-dose dihydroartemisinin-piperaquine group (34.1%, P=0.03) or the monthly dihydroartemisinin-piperaquine group (27.1%, P=0.001). The prevalence of a composite adverse birth outcome was lower in the monthly dihydroartemisinin-piperaquine group (9.2%) than in the sulfadoxine-pyrimethamine group (18.6%, P=0.05) or the three-dose dihydroartemisinin-piperaquine group (21.3%, P=0.02). During pregnancy, the incidence of symptomatic malaria was significantly higher in the sulfadoxine-pyrimethamine group (41 episodes over 43.0 person-years at risk) than in the three-dose dihydroartemisinin-piperaquine group (12 episodes over 38.2 person-years at risk, P=0.001) or the monthly dihydroartemisinin-piperaquine group (0 episodes over 42.3 person-years at risk, P<0.001), as was the prevalence of parasitemia (40.5% in the sulfadoxine-pyrimethamine group vs. 16.6% in the three-dose dihydroartemisinin-piperaquine group [P<0.001] and 5.2% in the monthly dihydroartemisinin-piperaquine group [P<0.001]). In each treatment group, the risk of vomiting after administration of any dose of the study agents was less than 0.4%, and there were no significant differences among the groups in the risk of adverse events. CONCLUSIONS: The burden of malaria in pregnancy was significantly lower among adolescent girls or women who received intermittent preventive treatment with dihydroartemisinin-piperaquine than among those who received sulfadoxine-pyrimethamine, and monthly treatment with dihydroartemisinin-piperaquine was superior to three-dose dihydroartemisinin-piperaquine with regard to several outcomes. (Funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development; ClinicalTrials.gov number, NCT02163447.).

Decline of FoxP3+ Regulatory CD4 T Cells in Peripheral Blood of Children Heavily Exposed to Malaria.

FoxP3+ regulatory CD4 T cells (Tregs) help to maintain the delicate balance between pathogen-specific immunity and immune-mediated pathology. Prior studies suggest that Tregs are induced by P. falciparum both in vivo and in vitro; however, the factors influencing Treg homeostasis during acute and chronic infections, and their role in malaria immunopathogenesis, remain unclear. We assessed the frequency and phenotype of Tregs in well-characterized cohorts of children residing in a region of high malaria endemicity in Uganda. We found that both the frequency and absolute numbers of FoxP3+ Tregs in peripheral blood declined markedly with increasing prior malaria incidence. Longitudinal measurements confirmed that this decline occurred only among highly malaria-exposed children. The decline of Tregs from peripheral blood was accompanied by reduced in vitro induction of Tregs by parasite antigen and decreased expression of TNFR2 on Tregs among children who had intense prior exposure to malaria. While Treg frequencies were not associated with protection from malaria, there was a trend toward reduced risk of symptomatic malaria once infected with P. falciparum among children with lower Treg frequencies. These data demonstrate that chronic malaria exposure results in altered Treg homeostasis, which may impact the development of antimalarial immunity in naturally exposed populations.

Efficacy and safety of three regimens for the prevention of malaria in young HIV-exposed Ugandan children: a randomized controlled trial.

OBJECTIVE: Trimethoprim-sulfamethoxazole prophylaxis is recommended for HIV-exposed infants until breastfeeding ends and HIV infection has been excluded. Extending prophylaxis with a focus on preventing malaria may be beneficial in high transmission areas. We investigated three regimens for the prevention of malaria in young HIV-exposed children. DESIGN: An open-label, randomized controlled trial. SETTING: Tororo, Uganda, a rural area with intense, year-round, malaria transmission. PARTICIPANTS: Two hundred infants aged 4-5 months enrolled and 186 randomized after cessation of breastfeeding and confirmed to be HIV uninfected (median 10 months of age). INTERVENTION: No chemoprevention, monthly sulfadoxine-pyrimethamine, daily trimethoprim-sulfamethoxazole or monthly dihydroartemisinin-piperaquine given from randomization to 24 months of age. MAIN OUTCOME MEASURES: The primary outcome was the incidence of malaria during the intervention period. Secondary outcomes included the incidence of hospitalization, diarrhoeal illness, or respiratory tract infection; prevalence of anaemia and asymptomatic parasitemia; measures of safety; and incidence of malaria over 1 year after the intervention was stopped. RESULTS: During the intervention, the incidence of malaria in the no chemoprevention group was 6.28 episodes per person-year at risk. Protective efficacy was 69% [95% confidence interval (95% CI) 53-80, P < 0.001] for dihydroartemisinin-piperaquine, 49% (95% CI 23-66, P = 0.001) for trimethoprim-sulfamethoxazole and 9% for sulfadoxine-pyrimethamine (95% CI -35 to 38, P = 0.65). There were no significant differences in any secondary outcomes, with the exception of a lower prevalence of asymptomatic parasitemia in the dihydroartemisinin-piperaquine arm. CONCLUSION: Monthly chemoprevention with dihydroartemisinin-piperaquine was well tolerated and associated with a significant reduction in malaria in young HIV-exposed children.

Loss and dysfunction of Vδ2⁺ γδ T cells are associated with clinical tolerance to malaria.

Although clinical immunity to malaria eventually develops among children living in endemic settings, the underlying immunologic mechanisms are not known. The Vδ2(+) subset of γδ T cells have intrinsic reactivity to malaria antigens, can mediate killing of Plasmodium falciparum merozoites, and expand markedly in vivo after malaria infection in previously naïve hosts, but their role in mediating immunity in children repeatedly exposed to malaria is unclear. We evaluated γδ T cell responses to malaria among 4-year-old children enrolled in a longitudinal study in Uganda. We found that repeated malaria was associated with reduced percentages of Vδ2(+) γδ T cells in peripheral blood, decreased proliferation and cytokine production in response to malaria antigens, and increased expression of immunoregulatory genes. Further, loss and dysfunction of proinflammatory Vδ2(+) γδ T cells were associated with a reduced likelihood of symptoms upon subsequent P. falciparum infection. Together, these results suggest that repeated malaria infection during childhood results in progressive loss and dysfunction of Vδ2(+) γδ T cells that may facilitate immunological tolerance of the parasite.

Protective efficacy and safety of three antimalarial regimens for the prevention of malaria in young Ugandan children: a randomized controlled trial.

BACKGROUND: Chemoprevention offers a promising strategy for prevention of malaria in African children. However, the optimal chemoprevention drug and dosing strategy is unclear in areas of year-round transmission and resistance to many antimalarial drugs. To compare three available regimens, we conducted an open-label randomized controlled trial of chemoprevention in Ugandan children. METHODS AND FINDINGS: This study was conducted between June 28, 2010, and September 25, 2013. 400 infants were enrolled and 393 randomized at 6 mo of age to no chemoprevention, monthly sulfadoxine-pyrimethamine (SP), daily trimethoprim-sulfamethoxazole (TS), or monthly dihydroartemisinin-piperaquine (DP). Study drugs were administered at home without supervision. Piperaquine (PQ) levels were used as a measure of compliance in the DP arm. Participants were given insecticide-treated bednets, and caregivers were encouraged to bring their child to a study clinic whenever they were ill. Chemoprevention was stopped at 24 mo of age, and participants followed-up an additional year. Primary outcome was the incidence of malaria during the intervention period. During the intervention, the incidence of malaria in the no chemoprevention arm was 6.95 episodes per person-year at risk. Protective efficacy was 58% (95% CI, 45%-67%, p<0.001) for DP, 28% (95% CI, 7%-44%, p = 0.01) for TS, and 7% for SP (95% CI, -19% to 28%, p = 0.57). PQ levels were below the detection limit 52% of the time when malaria was diagnosed in the DP arm, suggesting non-adherence. There were no differences between the study arms in the incidence of serious adverse events during the intervention and the incidence of malaria during the 1-y period after the intervention was stopped. CONCLUSIONS: For preventing malaria in children living in an area of high transmission intensity, monthly DP was the most efficacious and safe, although adherence may pose a problem. Monthly SP and daily TS may not be appropriate in areas with high transmission intensity and frequent resistance to antifolates. TRIAL REGISTRATION: www.ClinicalTrials.gov NCT00948896 Please see later in the article for the Editors' Summary.

Longitudinal outcomes in a cohort of Ugandan children randomized to artemether-lumefantrine versus dihydroartemisinin-piperaquine for the treatment of malaria.

BACKGROUND: Artemisinin-based combination therapy (ACT) has become the standard of care for the treatment of uncomplicated Plasmodium falciparum malaria. Although several ACT regimens are approved, data guiding optimal choices of ACTs are limited. We compared short- and long-term outcomes in a cohort of young Ugandan children randomized to 2 leading ACTs. METHODS: Overall, 312 children were randomized to artemether-lumefantrine or dihydroartemisinin-piperaquine (DP) at the time of the first episode of uncomplicated malaria (median age, 10.5 months). The same treatment was given for all subsequent episodes of uncomplicated malaria and children were followed until they reached 5 years of age. The cohort included a subgroup that was human immunodeficiency virus (HIV) infected (n = 44) or HIV exposed (n = 175) and prescribed trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis. Outcomes included time to recurrent malaria following individual treatments and the overall incidences of treatments for malaria, complicated malaria, and hospitalizations. RESULTS: Among children not prescribed TMP-SMX prophylaxis, 4443 treatments for malaria were given over 790 person-years following randomization. Treatment with DP was associated with a lower hazard of recurrent malaria over the 84 days after treatment (hazard ratio, 0.66; 95% confidence interval [CI], .61-.70; P < .001). Children randomized to DP had a lower incidence of all treatments for malaria (incidence rate ratio [IRR], 0.85; 95% CI, .75-.96; P = .01), complicated malaria (IRR, 0.12; 95% CI, .04-.39; P < .001), and hospitalizations (IRR, 0.31; 95% CI, .13-.77; P = .01). Among children prescribed TMP-SMX prophylaxis, there were no significant differences in longitudinal outcomes. CONCLUSIONS: Compared to artemether-lumefantrine, the use of DP to treat uncomplicated malaria delayed the time to recurrent malaria and reduced the incidences of treatments for malaria, complicated malaria, and hospitalizations. CLINICAL TRIALS REGISTRATION: NCT00527800.