Correction: Twitter and Facebook posts about COVID-19 are less likely to spread misinformation compared to other health topics.

[This corrects the article DOI: 10.1371/journal.pone.0261768.].

The correlation of non-invasive hemoglobin testing and lab hemoglobin in surgical patients: A systematic review and meta-analysis.

BACKGROUND: The decision regarding intraoperative transfusion has traditionally been based on hemodynamic instability and estimated blood loss. We performed a systematic review to determine the validity of the oximetry method compared to standard of care for hemoglobin measurement. METHODS: A systematic literature review was conducted, and several libraries were searched from inception to March 31,2023. The primary outcome was comparing the mean difference between laboratory-derived hemoglobin and non-invasive, point-of-care hemoglobin measurement. Subgroup analysis included comparing the mean difference in the pediatric population and among female patients. RESULTS: A total of 276 studies were identified, and 37 were included. We found that the pooled mean difference varied qualitatively between adult and pediatric population (p value for heterogeneity <0.001). In adult populations, lab hemoglobin measurements were on average slightly higher than non-invasive measurements (mean difference = 0.23; 95% CI -0.13, 0.59), though there was greater heterogeneity across studies (I2 = 97%, p value = <0.001). In the pediatric population, most studies showed lab hemoglobin to be slightly lower (mean difference = -0.42; 95% CI -0.87 to 0.03). CONCLUSIONS: In general, there was no clinically significant difference in mean hemoglobin among adult and pediatric populations. The percentage of female participants had no effect on the mean difference in hemoglobin.

Cohort profile: the Pregnancy Risk Infant Surveillance and Measurement Alliance (PRISMA) - Pakistan.

PURPOSE: Pakistan has disproportionately high maternal and neonatal morbidity and mortality. There is a lack of detailed, population-representative data to provide evidence for risk factors, morbidities and mortality among pregnant women and their newborns. The Pregnancy Risk, Infant Surveillance and Measurement Alliance (PRISMA) is a multicountry open cohort that aims to collect high-dimensional, standardised data across five South Asian and African countries for estimating risk and developing innovative strategies to optimise pregnancy outcomes for mothers and their newborns. This study presents the baseline maternal and neonatal characteristics of the Pakistan site occurring prior to the launch of a multisite, harmonised protocol. PARTICIPANTS: PRISMA Pakistan study is being conducted at two periurban field sites in Karachi, Pakistan. These sites have primary healthcare clinics where pregnant women and their newborns are followed during the antenatal, intrapartum and postnatal periods up to 1 year after delivery. All encounters are captured electronically through a custom-built Android application. A total of 3731 pregnant women with a mean age of 26.6±5.8 years at the time of pregnancy with neonatal outcomes between January 2021 and August 2022 serve as a baseline for the PRISMA Pakistan study. FINDINGS TO DATE: In this cohort, live births accounted for the majority of pregnancy outcomes (92%, n=3478), followed by miscarriages/abortions (5.5%, n=205) and stillbirths (2.6%, n=98). Twenty-two per cent of women (n=786) delivered at home. One out of every four neonates was low birth weight (<2500 g), and one out of every five was preterm (gestational age <37 weeks). The maternal mortality rate was 172/100 000 pregnancies, the neonatal mortality rate was 52/1000 live births and the stillbirth rate was 27/1000 births. The three most common causes of neonatal deaths obtained through verbal autopsy were perinatal asphyxia (39.6%), preterm births (19.8%) and infections (12.6%). FUTURE PLANS: The PRISMA cohort will provide data-driven insights to prioritise and design interventions to improve maternal and neonatal outcomes in low-resource regions. TRIAL REGISTRATION NUMBER: NCT05904145.

Comparison of Masimo Total Hemoglobin SpHb® continuous non-invasive hemoglobin monitoring device with laboratory complete blood count measurement using venous sample: Protocol for an observational substudy of the Pregnancy Risk and Infant Surveillance and Measurement Alliance Maternal and Newborn Health (PRISMA MNH) study.

Background: The Masimo Total Hemoglobin SpHb® is a continuous and non-invasive handheld device to measure hemoglobin levels. Previous research has found that SpHb is able to accurately detect hemoglobin levels in adult patients with a similar degree of bias and standard deviation to point-of-care invasive method measurements. Generally, limited clinical evidence, lack of validation of Masimo at higher than and lower than hemoglobin threshold values, and scientific consensus supporting the use of Masimo for accurate hemoglobin testing for the diagnosis of anemia during pregnancy calls for further research. Methods and analysis: The proposed prospective cohort will be nested within the ongoing Pregnancy Risk and Infant Surveillance and Measurement Alliance (PRISMA) Maternal and Newborn Health (MNH) study. Three study sites (located in Zambia, Kenya, and Pakistan) will participate and collect hemoglobin data at five time points (<20 weeks, 20 weeks, 28 weeks, 36 weeks' gestation, and six weeks postpartum). We will measure hemoglobin using a venous blood sample via hematology auto-analyzer complete blood count (gold standard) and the non-invasive device. The primary objective is to assess agreement between Masimo total hemoglobin and complete blood count and on a continuous scale using Intraclass Correlation Coefficient and Bland-Altman Analysis. The second objective is to assess agreement between the two measures on a binary scale using Positive Percentage Agreement and Negative Percentage Agreement, Cohen's Kappa, and McNemar Test. On an ordinal scale, agreement will be measured using Weighted Cohen's Kappa and Harrel's Concordance Index. Lastly, we will assess factors that might affect the accuracy of Masimo total hemoglobin using linear mixed models. Conclusions: The primary aim of this study is to assess the validity of the non-invasive Masimo device compared to the gold standard method of invasive hemoglobin measurements during pregnancy and postpartum periods for the diagnosis of anemia.

Adverse maternal, fetal, and newborn outcomes among pregnant women with SARS-CoV-2 infection: an individual participant data meta-analysis.

INTRODUCTION: Despite a growing body of research on the risks of SARS-CoV-2 infection during pregnancy, there is continued controversy given heterogeneity in the quality and design of published studies. METHODS: We screened ongoing studies in our sequential, prospective meta-analysis. We pooled individual participant data to estimate the absolute and relative risk (RR) of adverse outcomes among pregnant women with SARS-CoV-2 infection, compared with confirmed negative pregnancies. We evaluated the risk of bias using a modified Newcastle-Ottawa Scale. RESULTS: We screened 137 studies and included 12 studies in 12 countries involving 13 136 pregnant women.Pregnant women with SARS-CoV-2 infection-as compared with uninfected pregnant women-were at significantly increased risk of maternal mortality (10 studies; n=1490; RR 7.68, 95% CI 1.70 to 34.61); admission to intensive care unit (8 studies; n=6660; RR 3.81, 95% CI 2.03 to 7.17); receiving mechanical ventilation (7 studies; n=4887; RR 15.23, 95% CI 4.32 to 53.71); receiving any critical care (7 studies; n=4735; RR 5.48, 95% CI 2.57 to 11.72); and being diagnosed with pneumonia (6 studies; n=4573; RR 23.46, 95% CI 3.03 to 181.39) and thromboembolic disease (8 studies; n=5146; RR 5.50, 95% CI 1.12 to 27.12).Neonates born to women with SARS-CoV-2 infection were more likely to be admitted to a neonatal care unit after birth (7 studies; n=7637; RR 1.86, 95% CI 1.12 to 3.08); be born preterm (7 studies; n=6233; RR 1.71, 95% CI 1.28 to 2.29) or moderately preterm (7 studies; n=6071; RR 2.92, 95% CI 1.88 to 4.54); and to be born low birth weight (12 studies; n=11 930; RR 1.19, 95% CI 1.02 to 1.40). Infection was not linked to stillbirth. Studies were generally at low or moderate risk of bias. CONCLUSIONS: This analysis indicates that SARS-CoV-2 infection at any time during pregnancy increases the risk of maternal death, severe maternal morbidities and neonatal morbidity, but not stillbirth or intrauterine growth restriction. As more data become available, we will update these findings per the published protocol.

Impact of prepregnancy body mass index on adverse pregnancy outcomes: analysis from the Longitudinal Indian Family hEalth cohort study.

BACKGROUND: Both high and low maternal prepregnancy body mass index can lead to suboptimal fetal growth and risk of pregnancy complications. In developed countries, nearly half of all women of childbearing age are either overweight or obese, and most data linking maternal body mass index and adverse pregnancy complications are limited to these populations. OBJECTIVE: This study aimed to prospectively evaluate the relationships between prepregnancy body mass index and adverse pregnancy outcomes using the Longitudinal Indian Family hEalth (LIFE) study. STUDY DESIGN: We modeled the relationships between prepregnancy body mass index and adverse pregnancy outcomes such as low birthweight, preterm birth, cesarean delivery, intrauterine growth restriction, miscarriage, and fetal death among 675 women aged 15 to 35 years with singleton pregnancies in the Longitudinal Indian Family hEalth study, a population-based prospective pregnancy cohort study conducted in Telangana, India. Prepregnancy body mass index was calculated as weight in kilograms divided by height in meters squared and was classified into 4 categories using the World Health Organization recommendations for Asian adults. Prepregnancy body mass index was assessed at a mean of 12.3 months before pregnancy. Odds ratios and 95% confidence intervals of adverse pregnancy outcomes were modeled and adjusted for confounders. RESULTS: Obese women had a 3-fold increased risk of cesarean delivery (odds ratio, 3.13; 95% confidence interval, 1.56-6.29) compared with normal-weight women. Those who were overweight also had a marginally increased risk of cesarean delivery, albeit not statistically significant (odds ratio, 1.17; 95% confidence interval, 0.61-2.24). Underweight women had a modestly increased risk of low birthweight, compared with normal-weight women (odds ratio, 1.12; 95% confidence interval, 0.71-1.77), although results were not significant. Conversely, obese (odds ratio, 0.71; 95% confidence interval, 0.28-1.77) and overweight (odds ratio, 0.61; 95% confidence interval, 0.24-1.51) women had a marginally decreased risk of low birthweight. CONCLUSION: Our data suggest that women with elevated prepregnancy body mass index may have a higher risk of adverse pregnancy outcomes, especially cesarean delivery. Although this study has limited generalizability, our findings are generalizable to rural to periurban regions of India. Further studies exploring the translatability of these findings to other populations are needed. In addition, targeted prepregnancy intervention studies and programs that include counseling on optimization of preconception health and lifestyle modification for improvement of subsequent pregnancy outcomes among overweight and obese women are needed.

Clinical risk factors of adverse outcomes among women with COVID-19 in the pregnancy and postpartum period: a sequential, prospective meta-analysis.

OBJECTIVE: This sequential, prospective meta-analysis sought to identify risk factors among pregnant and postpartum women with COVID-19 for adverse outcomes related to disease severity, maternal morbidities, neonatal mortality and morbidity, and adverse birth outcomes. DATA SOURCES: We prospectively invited study investigators to join the sequential, prospective meta-analysis via professional research networks beginning in March 2020. STUDY ELIGIBILITY CRITERIA: Eligible studies included those recruiting at least 25 consecutive cases of COVID-19 in pregnancy within a defined catchment area. METHODS: We included individual patient data from 21 participating studies. Data quality was assessed, and harmonized variables for risk factors and outcomes were constructed. Duplicate cases were removed. Pooled estimates for the absolute and relative risk of adverse outcomes comparing those with and without each risk factor were generated using a 2-stage meta-analysis. RESULTS: We collected data from 33 countries and territories, including 21,977 cases of SARS-CoV-2 infection in pregnancy or postpartum. We found that women with comorbidities (preexisting diabetes mellitus, hypertension, cardiovascular disease) vs those without were at higher risk for COVID-19 severity and adverse pregnancy outcomes (fetal death, preterm birth, low birthweight). Participants with COVID-19 and HIV were 1.74 times (95% confidence interval, 1.12-2.71) more likely to be admitted to the intensive care unit. Pregnant women who were underweight before pregnancy were at higher risk of intensive care unit admission (relative risk, 5.53; 95% confidence interval, 2.27-13.44), ventilation (relative risk, 9.36; 95% confidence interval, 3.87-22.63), and pregnancy-related death (relative risk, 14.10; 95% confidence interval, 2.83-70.36). Prepregnancy obesity was also a risk factor for severe COVID-19 outcomes including intensive care unit admission (relative risk, 1.81; 95% confidence interval, 1.26-2.60), ventilation (relative risk, 2.05; 95% confidence interval, 1.20-3.51), any critical care (relative risk, 1.89; 95% confidence interval, 1.28-2.77), and pneumonia (relative risk, 1.66; 95% confidence interval, 1.18-2.33). Anemic pregnant women with COVID-19 also had increased risk of intensive care unit admission (relative risk, 1.63; 95% confidence interval, 1.25-2.11) and death (relative risk, 2.36; 95% confidence interval, 1.15-4.81). CONCLUSION: We found that pregnant women with comorbidities including diabetes mellitus, hypertension, and cardiovascular disease were at increased risk for severe COVID-19-related outcomes, maternal morbidities, and adverse birth outcomes. We also identified several less commonly known risk factors, including HIV infection, prepregnancy underweight, and anemia. Although pregnant women are already considered a high-risk population, special priority for prevention and treatment should be given to pregnant women with these additional risk factors.

Consanguineous Marriage and Early Pregnancy Loss in Rural to Peri-Urban India.

Background: Consanguineous marriage (CM) has been linked to spontaneous abortion (SAB), although studies have largely been cross-sectional and likely underestimated early loss. We aimed to determine the relationships between CM and SAB in a prospective pregnancy cohort study in Telangana State, India. Methods: Data from 661 participants aged 15-35 years in the Longitudinal Indian Family hEalth (LIFE) study actively followed for pregnancy and pregnancy loss were analyzed. SAB was classified as early (< 8) or late (8-22) weeks gestation. We used logistic regression to model the relationships between CM, defined by first-cousin marriage, and SAB, adjusted for maternal age. Results: Women in CM were at a modestly increased risk of any (ORadj 1.15, 95% CI 0.69, 1.91) and early (ORadj 2.03, 95% CI 0.85, 4.83) SAB compared to women in non-CM, although results were not statistically significant. There was no relationship between CM and late SAB. Conclusion: Among couples in southern India, there was a modest increase in early but not late SAB among CMs which may be explained by the expected influence of chromosomal abnormalities and lethal homozygous recessive disease on early loss. Pre- and Peri-marital Health Counseling that addresses this risk may be warranted. Supplementary Information: The online version contains supplementary material available at 10.1007/s13224-021-01498-7.

Twitter and Facebook posts about COVID-19 are less likely to spread misinformation compared to other health topics.

The COVID-19 pandemic brought widespread attention to an "infodemic" of potential health misinformation. This claim has not been assessed based on evidence. We evaluated if health misinformation became more common during the pandemic. We gathered about 325 million posts sharing URLs from Twitter and Facebook during the beginning of the pandemic (March 8-May 1, 2020) compared to the same period in 2019. We relied on source credibility as an accepted proxy for misinformation across this database. Human annotators also coded a subsample of 3000 posts with URLs for misinformation. Posts about COVID-19 were 0.37 times as likely to link to "not credible" sources and 1.13 times more likely to link to "more credible" sources than prior to the pandemic. Posts linking to "not credible" sources were 3.67 times more likely to include misinformation compared to posts from "more credible" sources. Thus, during the earliest stages of the pandemic, when claims of an infodemic emerged, social media contained proportionally less misinformation than expected based on the prior year. Our results suggest that widespread health misinformation is not unique to COVID-19. Rather, it is a systemic feature of online health communication that can adversely impact public health behaviors and must therefore be addressed.

A pathway level analysis of PFAS exposure and risk of gestational diabetes mellitus.

Per- and polyfluoroalkyl substances (PFAS) have been found to be associated with gestational diabetes mellitus (GDM) development, a maternal health disorder in pregnancy with negative effects that can extend beyond pregnancy. Studies that report on this association are difficult to summarize due to weak associations and wide confidence intervals. One way to advance this field is to sharpen the biologic theory on a causal pathway behind this association, and to measure it directly by way of molecular biomarkers. The aim of this review is to summarize the literature that supports a novel pathway between PFAS exposure and GDM development. Epidemiological studies demonstrate a clear association of biomarkers of thyroid hormones and glucose metabolism with GDM development. We report biologic plausibility and epidemiologic evidence that PFAS dysregulation of maternal thyroid hormones and thyrotropin (TSH) may disrupt glucose homeostasis, increasing the risk of GDM. Overall, epidemiological studies demonstrate that PFAS were positively associated with TSH and negatively with triiodothyronine (T3) and thyroxine (T4). PFAS were generally positively associated with glucose and insulin levels in pregnancy. We propose dysregulation of thyroid function and glucose metabolism may be a critical and missing component in the accurate estimation of PFAS on the risk of GDM.

Optimized flow cytometric protocol for the detection of functional subsets of low frequency antigen-specific CD4+ and CD8+ T cells.

Detection of low-frequency cells using flow cytometry is challenging, as the sensitivity of the analysis is dependent on the signal-to-noise ratio, and a cell frequency of 1 in 10,000 cells is accepted as the lower limit of detection for standard flow cytometry. A solution to this problem is to pre-enrich rare cell populations using magnetic-bead conjugated antibodies targeting lineage or activation markers. For measuring vaccine or pathogen induced immune responses, this method drastically increases the signal-to-noise ratio by enriching only activated (i.e., antigen-specific) cells and excluding all other peripheral blood leukocytes from the subsequent analysis. To date, magnetic enrichment of antigen-specific cells has only been described for CD4+ T cells processed for surface staining. The current study significantly expands the methodology to allow detection of antigen-specific CD8+ T cells and analysis of cells that had been processed for intracellular staining.•The protocol described here allows magnetic enrichment of PBMCs after fixation and intracellular staining steps without increasing the non-specific background.•The protocol is adapted to automated enrichment-mode on flow cytometers.•The procedure boosts the sensitivity of the flow cytometry analysis by significantly increasing the sample size of functional antigen-specific cells without skewing the composition of the functional cells pool.

Presence and Concentrations of Select Bacterial Vaginosis-Associated Bacteria Are Associated With Increased Risk of Pelvic Inflammatory Disease.

In a vaginal 16S ribosomal RNA gene quantitative PCR study of 17 pelvic inflammatory disease (PID) cases and 17 controls who tested positive for Chlamydia trachomatis, women who additionally tested positive for Atopobium vaginae, Sneathia spp., Megasphaera spp., Eggerthella-like bacterium or Prevotella amnii were more likely to develop PID.

Correction: Vaccine Strain-Specificity of Protective HLA-Restricted Class 1 P. falciparum Epitopes.

[This corrects the article DOI: 10.1371/journal.pone.0163026.].

Vaccine Strain-Specificity of Protective HLA-Restricted Class 1 P. falciparum Epitopes.

A DNA prime/adenovirus boost malaria vaccine encoding Plasmodium falciparum strain 3D7 CSP and AMA1 elicited sterile clinical protection associated with CD8+ T cell interferon-gamma (IFN-γ) cells responses directed to HLA class 1-restricted AMA1 epitopes of the vaccine strain 3D7. Since a highly effective malaria vaccine must be broadly protective against multiple P. falciparum strains, we compared these AMA1 epitopes of two P. falciparum strains (7G8 and 3D7), which differ by single amino acid substitutions, in their ability to recall CD8+ T cell activities using ELISpot and flow cytometry/intracellular staining assays. The 7G8 variant peptides did not recall 3D7 vaccine-induced CD8+ T IFN-γ cell responses in these assays, suggesting that protection may be limited to the vaccine strain. The predicted MHC binding affinities of the 7G8 variant epitopes were similar to the 3D7 epitopes, suggesting that the amino acid substitutions of the 7G8 variants may have interfered with TCR recognition of the MHC:peptide complex or that the 7G8 variant may have acted as an altered peptide ligand. These results stress the importance of functional assays in defining protective epitopes. Clinical Trials Registrations: NCT00870987, NCT00392015.

Circulating follicular T helper cells and cytokine profile in humans following vaccination with the rVSV-ZEBOV Ebola vaccine.

The most recent Zaire Ebolavirus (ZEBOV) outbreak was the largest and most widespread in recorded history, emphasizing the need for an effective vaccine. Here, we analyzed human cellular immune responses induced by a single dose of the rVSV-ZEBOV vaccine candidate, which showed significant protective efficacy in endemic populations in Guinea. This is the first in-depth characterization of ZEBOV-GP specific, circulating follicular T cells (cTfh). Since antibody titers correlated with protection in preclinical models of ZEBOV infection, Tfh were predicted to correlate with protection. Indeed, the ZEBOV-specific cTfh data correlated with antibody titers in human vaccines and unexpectedly with the Tfh17 subset. The combination of two cutting edge technologies allowed the immuno-profiling of rare cell populations and may help elucidate correlates of protection for a variety of vaccines.

Immune Escape Mechanisms are Plasmodium's Secret Weapons Foiling the Success of Potent and Persistently Efficacious Malaria Vaccines.

Despite decades of active research, an efficacious vaccine mediating long-term protection is still not available. This review highlights various mechanisms and the different facets by which the parasites outsmart the immune system. An understanding of how the parasites escape immune recognition and interfere with the induction of a protective immune response that provides sterilizing immunity will be crucial to vaccine design.

Controlled Human Malaria Infection (CHMI) differentially affects cell-mediated and antibody responses to CSP and AMA1 induced by adenovirus vaccines with and without DNA-priming.

We have previously shown that a DNA-prime followed by an adenovirus-5 boost vaccine containing CSP and AMA1 (DNA/Ad) successfully protected 4 of 15 subjects to controlled human malaria infection (CHMI). However, the adenovirus-5 vaccine alone (AdCA) failed to induce protection despite eliciting cellular responses that were often higher than those induced by DNA/Ad. Here we determined the effect of CHMI on pre-CHMI cellular and antibody responses against CSP and AMA1 expressed as fold-changes in activities. Generally, in the DNA/Ad trial, CHMI caused pre-CHMI ELISpot IFN-γ and CD8+ T cell IFN-γ responses of the protected subjects to fall but among non-protected subjects, CHMI caused rises of pre-CHMI ELISpot IFN-γ but falls of CD8+ T cell IFN-γ responses. In contrast in the AdCA trial, CHMI caused both pre-CHMI ELISpot IFN-γ and CD8+ T cell IFN-γ responses of the AdCA subjects to fall. We suggest that the falls in activities are due to migration of peripheral CD8+ T cells to the liver in response to developing liver stage parasites, and this fall, in the DNA/Ad trial, is masked in ELISpot responses of the non-protected subjects by rises in other immune cell types. In addition, CHMI caused falls in antibody activities of protected subjects, but rises in non-protected subjects in both trials to CSP, and dramatically in the AdCA trial to AMA1, reaching 380 µg/ml that is probably due to boosting by transient blood stage infection before chloroquine treatment. Taken together, these results further define differences in cellular responses between DNA/Ad and AdCA trials, and suggest that natural transmission may boost responses induced by these malaria vaccines especially when protection is not achieved.

Sterile immunity to malaria after DNA prime/adenovirus boost immunization is associated with effector memory CD8+T cells targeting AMA1 class I epitopes.

BACKGROUND: Fifteen volunteers were immunized with three doses of plasmid DNA encoding P. falciparum circumsporozoite protein (CSP) and apical membrane antigen-1 (AMA1) and boosted with human adenovirus-5 (Ad) expressing the same antigens (DNA/Ad). Four volunteers (27%) demonstrated sterile immunity to controlled human malaria infection and, overall, protection was statistically significantly associated with ELISpot and CD8+ T cell IFN-γ activities to AMA1 but not CSP. DNA priming was required for protection, as 18 additional subjects immunized with Ad alone (AdCA) did not develop sterile protection. METHODOLOGY/PRINCIPAL FINDINGS: We sought to identify correlates of protection, recognizing that DNA-priming may induce different responses than AdCA alone. Among protected volunteers, two and three had higher ELISpot and CD8+ T cell IFN-γ responses to CSP and AMA1, respectively, than non-protected volunteers. Unexpectedly, non-protected volunteers in the AdCA trial showed ELISpot and CD8+ T cell IFN-γ responses to AMA1 equal to or higher than the protected volunteers. T cell functionality assessed by intracellular cytokine staining for IFN-γ, TNF-α and IL-2 likewise did not distinguish protected from non-protected volunteers across both trials. However, three of the four protected volunteers showed higher effector to central memory CD8+ T cell ratios to AMA1, and one of these to CSP, than non-protected volunteers for both antigens. These responses were focused on discrete regions of CSP and AMA1. Class I epitopes restricted by A*03 or B*58 supertypes within these regions of AMA1 strongly recalled responses in three of four protected volunteers. We hypothesize that vaccine-induced effector memory CD8+ T cells recognizing a single class I epitope can confer sterile immunity to P. falciparum in humans. CONCLUSIONS/SIGNIFICANCE: We suggest that better understanding of which epitopes within malaria antigens can confer sterile immunity and design of vaccine approaches that elicit responses to these epitopes will increase the potency of next generation gene-based vaccines.

Human adenovirus 5-vectored Plasmodium falciparum NMRC-M3V-Ad-PfCA vaccine encoding CSP and AMA1 is safe, well-tolerated and immunogenic but does not protect against controlled human malaria infection.

BACKGROUND: In a prior study, a DNA prime / adenovirus boost vaccine (DNA/Ad) expressing P. falciparum circumsporozoite protein (CSP) and apical membrane antigen-1 (AMA1) (NMRC-M3V-D/Ad-PfCA Vaccine) induced 27% protection against controlled human malaria infection (CHMI). To investigate the contribution of DNA priming, we tested the efficacy of adenovirus vaccine alone (NMRC-M3V-Ad-PfCA ) in a Phase 1 clinical trial. METHODOLOGY/PRINCIPAL FINDINGS: The regimen was a single intramuscular injection with two non-replicating human serotype 5 adenovectors encoding CSP and AMA1, respectively. One x 10 (10) particle units of each construct were combined prior to administration. The regimen was safe and well-tolerated. Four weeks later, 18 study subjects received P. falciparum CHMI administered by mosquito bite. None were fully protected although one showed delayed onset of parasitemia. Antibody responses were low, with geometric mean CSP ELISA titer of 381 (range<50-1626) and AMA1 ELISA of 4.95 µg/mL (range 0.2-38). Summed ex vivo IFN-γ ELISpot responses to overlapping peptides were robust, with geometric mean spot forming cells/million peripheral blood mononuclear cells [sfc/m] for CSP of 273 (range 38-2550) and for AMA1 of 1303 (range 435-4594). CD4+ and CD8+ T cell IFN-γ responses to CSP were positive by flow cytometry in 25% and 56% of the research subjects, respectively, and to AMA1 in 94% and 100%, respectively. SIGNIFICANCE: In contrast to DNA/Ad, Ad alone did not protect against CHMI despite inducing broad, cell-mediated immunity, indicating that DNA priming is required for protection by the adenovirus-vectored vaccine. ClinicalTrials.gov Identifier: NCT00392015.