Controlled Human Malaria Infection in Semi-Immune Kenyan Adults (CHMI-SIKA): a study protocol to investigate in vivo Plasmodium falciparum malaria parasite growth in the context of pre-existing immunity [version 2; peer review: 2 approved]

Malaria remains a major public health burden despite approval for implementation of a partially effective pre-erythrocytic malaria vaccine. There is an urgent need to accelerate development of a more effective multi-stage vaccine. Adults in malaria endemic areas may have substantial immunity provided by responses to the blood stages of malaria parasites, but field trials conducted on several blood-stage vaccines have not shown high levels of efficacy. We will use the controlled human malaria infection (CHMI) models with malaria-exposed volunteers to identify correlations between immune responses and parasite growth rates in vivo. Immune responses more strongly associated with control of parasite growth should be prioritized to accelerate malaria vaccine development. We aim to recruit up to 200 healthy adult volunteers from areas of differing malaria transmission in Kenya, and after confirming their health status through clinical examination and routine haematology and biochemistry, we will comprehensively characterize immunity to malaria using >100 blood-stage antigens. We will administer 3,200 aseptic, purified, cryopreserved Plasmodium falciparum sporozoites (PfSPZ Challenge) by direct venous inoculation. Serial quantitative polymerase chain reaction to measure parasite growth rate in vivo will be undertaken. Clinical and laboratory monitoring will be undertaken to ensure volunteer safety. In addition, we will also explore the perceptions and experiences of volunteers and other stakeholders in participating in a malaria volunteer infection study. Serum, plasma, peripheral blood mononuclear cells and whole blood will be stored to allow a comprehensive assessment of adaptive and innate host immunity. We will use CHMI in semi-immune adult volunteers to relate parasite growth outcomes with antibody responses and other markers of host immunity. / Registration: ClinicalTrials.gov identifier NCT02739763

Infrared Spectra of Isomers of Protonated Aniline in Solid para-Hydrogen

The protonation sites of aniline molecule play important roles in its chemical reactions, but the preferred protonation site of gaseous aniline has yet to be determined. In this work, we recorded infrared (IR) absorption spectra of three isomers of protonated aniline, H+C6H5NH2, produced on electron bombardment during matrix deposition at 3.2 K of a mixture of aniline and para-H2. The intensities of IR lines of H+C6H5NH2 decreased during maintenance of the electron-bombarded matrix in darkness because of neutralization with electrons that were slowly released from their trapping sites. The observed lines were classified into three groups according to their behavior upon secondary photolysis with light at 375 and 254 nm and assigned to para-, amino-, and ortho-H+C6H5NH2, the three most stable isomers of protonated aniline, according to comparison of experimental spectra with quantum-chemically predicted spectra of five possible isomers of H+C6H5NH2. The spectra of para- and ortho-H+C6H5NH2 are newly distinguished. The approximate relative abundance of these isomers in solid p-H2 was para:amino:ortho ≈ (1.0 ± 0.1):(1.0 ± 0.6):(0.6 ± 0.1). The possible mechanisms of formation are discussed

Four-year efficacy of RTS,S/AS01E and its interaction with malaria exposure.

BACKGROUND: The candidate malaria vaccine RTS,S/AS01E has entered phase 3 trials, but data on long-term outcomes are limited. METHODS: For 4 years, we followed children who had been randomly assigned, at 5 to 17 months of age, to receive three doses of RTS,S/AS01E vaccine (223 children) or rabies vaccine (224 controls). The end point was clinical malaria (temperature of ≥37.5°C and Plasmodium falciparum parasitemia density of >2500 parasites per cubic millimeter). Each child's exposure to malaria was estimated with the use of the distance-weighted local prevalence of malaria. RESULTS: Over a period of 4 years, 118 of 223 children who received the RTS,S/AS01E vaccine and 138 of 224 of the controls had at least 1 episode of clinical malaria. Vaccine efficacies in the intention-to-treat and per-protocol analyses were 29.9% (95% confidence interval [CI], 10.3 to 45.3; P=0.005) and 32.1% (95% CI, 11.6 to 47.8; P=0.004), respectively, calculated by Cox regression. Multiple episodes were common, with 551 and 618 malarial episodes in the RTS,S/AS01E and control groups, respectively; vaccine efficacies in the intention-to-treat and per-protocol analyses were 16.8% (95% CI, -8.6 to 36.3; P=0.18) and 24.3% (95% CI, 1.9 to 41.6; P=0.04), respectively, calculated by the Andersen-Gill extension of the Cox model. For every 100 vaccinated children, 65 cases of clinical malaria were averted. Vaccine efficacy declined over time (P=0.004) and with increasing exposure to malaria (P=0.001) in the per-protocol analysis. Vaccine efficacy was 43.6% (95% CI, 15.5 to 62.3) in the first year but was -0.4% (95% CI, -32.1 to 45.3) in the fourth year. Among children with a malaria-exposure index that was average or lower than average, the vaccine efficacy was 45.1% (95% CI, 11.3 to 66.0), but among children with a malaria-exposure index that was higher than average it was 15.9% (95% CI, -11.0 to 36.4). CONCLUSIONS: The efficacy of RTS,S/AS01E vaccine over the 4-year period was 16.8%. Efficacy declined over time and with increasing malaria exposure. (Funded by the PATH Malaria Vaccine Initiative and Wellcome Trust; ClinicalTrials.gov number, NCT00872963.)

Kilifi Malaria Longitudinal Cohort cross-sectional survey and weekly-follow-up surveillance data for the estimation of parasite prevalence and factors associated with gametocyte carriage

Data from a longitudinally monitored cohort of children from Kilifi county located along the Kenyan coast collected between 1998-2016 were analysed to describe the distribution and prevalence of gametocytaemia in relation to transmission intensity, time and age. The datasets comprise data from cross-sectional surveys and weekly follow-up visits carried out within the Kilifi Malaria Longitudinal Cohort based in Kilifi County, Kenya on children aged between 0 – 15 years. The datasets were used to carry out analyses aimed at describing the prevalence of gametocyte carriage in this cohort as well as factors that predispose gametocyte carriage. The overall aim of the analyses was to identify prognostic indicators of populations contributing disproportionately to the infectious reservoir of malaria

Simplifying the ShangRing technique for circumcision in boys and men: Use of the no-flip technique with randomization to removal at 7 days versus spontaneous detachment

To assess safety of the no-flip ShangRing male circumcision technique and to determine clinical course and safety of spontaneous detachment (i.e., allowing the device to fall off), we conducted a case series of no-flip ShangRing circumcision combined with a randomized controlled trial of removal 7 days postcircumcision versus spontaneous detachment at two health facilities in Kenya. The primary outcome was the safety of the no-flip technique based on moderate and severe adverse events (AEs) during the procedure and through 42-day follow-up. A main secondary outcome was clinical course and safety of spontaneous detachment. Two hundred and thirty males 10 years and older underwent no-flip circumcision; 114 randomized to 7-day removal and 116 to spontaneous detachment. All circumcisions were successfully completed. Overall 5.3% (6/114) of participants in the 7-day group and 1.7% (2/116) in the spontaneous group had an AE; with no differences when compared to the 3% AE rate in historical data from African studies using the original flip technique (P = 0.07 and P = 0.79, respectively). Overall 72.4% (84/116) of participants in the spontaneous group wore the ShangRing until it detached. Among the remaining (27.6%; 32/116), the ring was removed, primarily at the participants\u27 request, due to pain or discomfort. There was no difference in AE rates (P = 0.169), visit day declared healed (P = 0.324), or satisfaction (P = 0.371) between randomization groups. The median time to detachment was 14.0 (IQR: 7–21, range: 5–35) days. The no-flip technique and spontaneous detachment are safe, effective, and acceptable to boys and men 10 years and older. Phimosis and penile adhesions do not limit successful ShangRing circumcision with the no-flip technique. See also: Wang, Yi-Fei. Commentary on “Simplifying the ShangRing technique for circumcision in boys and men: Use of the no-flip technique with randomization to removal at 7 days versus spontaneous detachment.” Asian Journal of Andrology 21(4):423-424. Available from: http://www.ajandrology.com/text.asp?2019/21/4/423/25815

Kilifi Malaria Longitudinal Cohort cross-sectional survey and weekly-follow-up surveillance data for the estimation of parasite prevalence and factors associated with gametocyte carriage.

Data from a longitudinally monitored cohort of children from Kilifi county located along the Kenyan coast collected between 1998-2016 were analysed to describe the distribution and prevalence of gametocytaemia in relation to transmission intensity, time and age. The datasets comprise data from cross-sectional surveys and weekly follow-up visits carried out within the Kilifi Malaria Longitudinal Cohort based in Kilifi County, Kenya on children aged between 0 – 15 years. The datasets were used to carry out analyses aimed at describing the prevalence of gametocyte carriage in this cohort as well as factors that predispose gametocyte carriage. The overall aim of the analyses was to identify prognostic indicators of populations contributing disproportionately to the infectious reservoir of malaria. </p

Use of topical versus injectable anaesthesia for ShangRing circumcisions in men and boys in Kenya: Results from a randomized controlled trial

Background: The ShangRing is a disposable, collar clamp circumcision device pre-qualified for use in men and boys 13 years and above. It has been shown to be faster than conventional circumcision with comparable adverse event (AE) rates and high client satisfaction. Voluntary medical male circumcision (VMMC) has been shown to dramatically reduce the risk of HIV acquisition in males. However, the fear of pain during circumcision is an important barrier to uptake. Use of topical anesthesia thus presents an opportunity to address this. Objectives: We sought to evaluate the safety, effectiveness and acceptability of the use of topical anaesthesia with ShangRing circumcision of men and boys 10 years of age and above. Methods: Participants were randomised 2:1 to receive topical or injectable anaesthesia. All participants underwent no-flip ShangRing circumcision. The primary outcome measure was pain. Secondary outcomes included ease of use of topical versus injectable anaesthesia, AEs and participant satisfaction. Results: Compared to the topical group, participants in the injectable group reported significantly more pain on administration of the anesthesia and at approximately 20 minutes after the procedure. In the topical group, sufficient anaesthesia with topical cream was not achieved in 21 (9.3%) cases before the start of the procedure; in another 6 (2.6%), supplementary injectable anaesthesia was required as the circumcision was being carried out. The AE rate was significantly lower (p \u3c 0.01) in the topical (0%) vs. the injectable group (4.2%). The most common AE was pain during the post-operative period. All AEs were managed conservatively and resolved without sequeale. 96.7% of participants were satisfied with the appearance of the healed penis and 100% would recommend the ShangRing to others. All seven male circumcision providers involved in the study preferred topical to injectable anaesthesia. Conclusions: Our results demonstrate the safety, improved clinical experience, effectiveness, and acceptability of the use of topical anaesthesia in ShangRing circumcision using the no-flip technique. Topical anaesthesia effectively eliminates needlestick pain from the clients’ VMMC experience and thus has the potential to increase demand for the service