Showing papers by "Moses R. Kamya published in 2022"

Resurgence of malaria in Uganda despite sustained indoor residual spraying and repeated long lasting insecticidal net distributions

Abstract: Five years of sustained indoor residual spraying (IRS) of insecticide from 2014 to 2019, first using a carbamate followed by an organophosphate, was associated with a marked reduction in the burden of malaria in five districts of Uganda. We assessed malaria burden over an additional 21 months, corresponding to a change in IRS formulations using clothianidin with and without deltamethrin and the start of the COVID-19 pandemic. We document an unprecedented resurgence in malaria burden: in years 4-5 of sustained IRS cases were 84% lower than the pre-IRS period, in year 6 this increased to a 43% reduction, and in the first 9 months of year 7, cases were 39% higher than pre-IRS levels. The timing of this resurgence corresponded to a change of active ingredient to clothianidin, a new IRS active ingredient. Further research is needed to determine mechanisms leading to this resurgence.

Gender difference in the incidence of malaria diagnosed at public health facilities in Uganda

Abstract: Routine malaria surveillance data in Africa primarily come from public health facilities reporting to national health management information systems. Although information on gender is routinely collected from patients presenting to these health facilities, stratification of malaria surveillance data by gender is rarely done. This study evaluated gender difference among patients diagnosed with parasitological confirmed malaria at public health facilities in Uganda.This study utilized individual level patient data collected from January 2020 through April 2021 at 12 public health facilities in Uganda and cross-sectional surveys conducted in target areas around these facilities in April 2021. Associations between gender and the incidence of malaria and non-malarial visits captured at the health facilities from patients residing within the target areas were estimated using poisson regression models controlling for seasonality. Associations between gender and data on health-seeking behaviour from the cross-sectional surveys were estimated using poisson regression models controlling for seasonality.Overall, incidence of malaria diagnosed per 1000 person years was 735 among females and 449 among males (IRR = 1.72, 95% CI 1.68-1.77, p < 0.001), with larger differences among those 15-39 years (IRR = 2.46, 95% CI 2.34-2.58, p < 0.001) and over 39 years (IRR = 2.26, 95% CI 2.05-2.50, p < 0.001) compared to those under 15 years (IRR = 1.46, 95% CI 1.41-1.50, p < 0.001). Female gender was also associated with a higher incidence of visits where malaria was not suspected (IRR = 1.77, 95% CI 1.71-1.83, p < 0.001), with a similar pattern across age strata. These associations were consistent across the 12 individual health centres. From the cross-sectional surveys, females were more likely than males to report fever in the past 2 weeks and seek care at the local health centre (7.5% vs. 4.7%, p = 0.001) with these associations significant for those 15-39 years (RR = 2.49, 95% CI 1.17-5.31, p = 0.018) and over 39 years (RR = 2.56, 95% CI 1.00-6.54, p = 0.049).Females disproportionately contribute to the burden of malaria diagnosed at public health facilities in Uganda, especially once they reach childbearing age. Contributing factors included more frequent visits to these facilities independent of malaria and a higher reported risk of seeking care at these facilities for febrile illnesses.

Measures of malaria transmission, infection, and disease in an area bordering two districts with and without sustained indoor residual spraying of insecticide in Uganda

Abstract: Tororo District, in Eastern Uganda, experienced a dramatic decline in malaria burden starting in 2014 following the implementation of indoor residual spraying of insecticide (IRS) in the setting of repeated long-lasting insecticide treated nets (LLINs) distribution campaigns. However, in 2020 malaria began to resurge in Tororo following a change in the active ingredient used for IRS. In this study, epidemiological measures of malaria were compared shortly after the resurgence between two parishes in Tororo District (Kayoro and Osukuru) and one contiguous parish in Busia District (Buteba), where IRS has never been implemented. A cohort of 483 residents from 80 randomly selected households were followed from August 2020 to January 2021. Mosquitoes were collected every 2 weeks using CDC light traps in rooms where participants slept; parasitemia and gametoctyemia measured every 4 weeks by microscopy and PCR; and symptomatic malaria measured by passive surveillance. The annual entomological inoculation rate was significantly higher in Buteba (108.2 infective bites/person/year), compared to Osukuru (59.0, p = 0.001) and Kayoro (27.4, p<0.001). Overall, parasite prevalence was 19.5% by microscopy and 50.7% by PCR, with no significant differences between the three parishes. Among infected individuals, gametocyte prevalence by PCR was 45.5% and similar between sites. The incidence of malaria was significantly higher in Osukuru (2.46 episodes PPY) compared to Buteba (1.47, p = 0.005) and Kayoro (1.09, p<0.001). For participants over 15 years of age, the risk of symptomatic malaria if microscopic parasitemia was present was higher in Osukuru (relative risk [RR] = 2.99, p = 0.03) compared to Buteba. These findings highlight the complex relationships between measures of malaria transmission, infection, and disease, and the potential for excess disease burden, possibly due to waning immunity, in areas where vector control interventions begin to fail after a sustained period of highly effective control.

Haematological consequences of acute uncomplicated falciparum malaria: a WorldWide Antimalarial Resistance Network pooled analysis of individual patient data

Abstract: Abstract Background Plasmodium falciparum malaria is associated with anaemia-related morbidity, attributable to host, parasite and drug factors. We quantified the haematological response following treatment of uncomplicated P. falciparum malaria to identify the factors associated with malarial anaemia. Methods Individual patient data from eligible antimalarial efficacy studies of uncomplicated P. falciparum malaria, available through the WorldWide Antimalarial Resistance Network data repository prior to August 2015, were pooled using standardised methodology. The haematological response over time was quantified using a multivariable linear mixed effects model with nonlinear terms for time, and the model was then used to estimate the mean haemoglobin at day of nadir and day 7. Multivariable logistic regression quantified risk factors for moderately severe anaemia (haemoglobin < 7 g/dL) at day 0, day 3 and day 7 as well as a fractional fall ≥ 25% at day 3 and day 7. Results A total of 70,226 patients, recruited into 200 studies between 1991 and 2013, were included in the analysis: 50,859 (72.4%) enrolled in Africa, 18,451 (26.3%) in Asia and 916 (1.3%) in South America. The median haemoglobin concentration at presentation was 9.9 g/dL (range 5.0–19.7 g/dL) in Africa, 11.6 g/dL (range 5.0–20.0 g/dL) in Asia and 12.3 g/dL (range 6.9–17.9 g/dL) in South America. Moderately severe anaemia (Hb < 7g/dl) was present in 8.4% (4284/50,859) of patients from Africa, 3.3% (606/18,451) from Asia and 0.1% (1/916) from South America. The nadir haemoglobin occurred on day 2 post treatment with a mean fall from baseline of 0.57 g/dL in Africa and 1.13 g/dL in Asia. Independent risk factors for moderately severe anaemia on day 7, in both Africa and Asia, included moderately severe anaemia at baseline (adjusted odds ratio (AOR) = 16.10 and AOR = 23.00, respectively), young age (age < 1 compared to ≥ 12 years AOR = 12.81 and AOR = 6.79, respectively), high parasitaemia (AOR = 1.78 and AOR = 1.58, respectively) and delayed parasite clearance (AOR = 2.44 and AOR = 2.59, respectively). In Asia, patients treated with an artemisinin-based regimen were at significantly greater risk of moderately severe anaemia on day 7 compared to those treated with a non-artemisinin-based regimen (AOR = 2.06 [95%CI 1.39–3.05], p < 0.001). Conclusions In patients with uncomplicated P. falciparum malaria, the nadir haemoglobin occurs 2 days after starting treatment. Although artemisinin-based treatments increase the rate of parasite clearance, in Asia they are associated with a greater risk of anaemia during recovery.

In Utero Activation of Natural Killer Cells in Congenital Cytomegalovirus Infection

Abstract: 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 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-negative 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. Conclusion 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.

Prevalence of arps10, fd, pfmdr-2, pfcrt and pfkelch13 gene mutations in Plasmodium falciparum parasite population in Uganda

Abstract: In Uganda, Artemether-Lumefantrine and Artesunate are recommended for uncomplicated and severe malaria respectively, but are currently threatened by parasite resistance. Genetic and epigenetic factors play a role in predisposing Plasmodium falciparum parasites to acquiring Pfkelch13 (K13) mutations associated with delayed artemisinin parasite clearance as reported in Southeast Asia. In this study, we report on the prevalence of mutations in the K13, pfmdr-2 (P. falciparum multidrug resistance protein 2), fd (ferredoxin), pfcrt (P. falciparum chloroquine resistance transporter), and arps10 (apicoplast ribosomal protein S10) genes in Plasmodium falciparum parasites prior to (2005) and after (2013) introduction of artemisinin combination therapies for malaria treatment in Uganda. A total of 200 P. falciparum parasite DNA samples were screened. Parasite DNA was extracted using QIAamp DNA mini kit (Qiagen, GmbH, Germany) procedure. The PCR products were sequenced using Sanger dideoxy sequencing method. Of the 200 P. falciparum DNA samples screened, sequencing for mutations in K13, pfmdr-2, fd, pfcrt, arps10 genes was successful in 142, 186, 141, 128 and 74 samples respectively. Overall, we detected six (4.2%, 6/142; 95%CI: 1.4–7.0) K13 single nucleotide polymorphisms (SNPs), of which 3.9% (2/51), 4.4% (4/91) occurred in 2005 and 2013 samples respectively. All four K13 SNPs in 2013 samples were non-synonymous (A578S, E596V, S600C and E643K) while of the two SNPs in 2005 samples, one (Y588N) is non-synonymous and the other (I587I) is synonymous. There was no statistically significant difference in the prevalence of K13 (p = 0.112) SNPs in the samples collected in 2005 and 2013. The overall prevalence of SNPs in pfmdr-2 gene was 39.8% (74/186, 95%CI: 25.1–50.4). Of this, 4.2% (4/95), 76.9% (70/91) occurred in 2005 and 2013 samples respectively. In 2005 samples only one SNP, Y423F (4.2%, 4/95) was found while in 2013, Y423F (38.5%, 35/91) and I492V (38.5%, 35/91) SNPs in the pfmdr-2 gene were found. There was a statistically significant difference in the prevalence of pfmdr-2 SNPs in the samples collected in 2005 and 2013 (p<0.001). The overall prevalence of arps10 mutations was 2.7% (2/72, 95%CI: 0.3–4.2). Two mutations, V127M (4.5%: 1/22) and D128H (4.5%: 1/22) in the arps10 gene were each found in P. falciparum parasite samples collected in 2013. There was no statistically significant difference in the prevalence of arps10 SNPs in the samples collected in 2005 and 2013 (p = 0.238). There were more pfmdr-2 SNPs in P. falciparum parasites collected after introduction of Artemisinin combination therapies in malaria treatment. This is an indicator of the need for continuous surveillance to monitor emergence of molecular markers of artemisinin resistance and its potential drivers in malaria affected regions globally.

Effect of long-lasting insecticidal nets with and without piperonyl butoxide on malaria indicators in Uganda (LLINEUP): final results of a cluster-randomised trial embedded in a national distribution campaign.

Abstract: Long-lasting insecticidal nets (LLINs) are the foundation of malaria control but resistance of mosquito vectors to pyrethroids threatens their effectiveness. We embedded a cluster-randomised trial into Uganda's 2017-18 campaign to distribute LLINs. LLINs with piperonyl butoxide (PBO) reduced parasite prevalence more effectively than conventional LLINs (without PBO) for 18 months. Here, we report the final 25-month survey results.LLINEUP was a cluster-randomised trial conducted in 48 districts in eastern and western Uganda. 104 health subdistricts (clusters) without ongoing or planned indoor residual spraying with pirimiphos-methyl (Actellic, Basel, Switzerland) were eligible for inclusion in the trial. Clusters were randomly assigned to PBO LLINs (PermaNet 3.0 or Olyset Plus) and conventional LLINs (PermaNet 2.0 or Olyset Net) with proportionate randomisation using STATA version 14.2. LLINs were delivered from March 25, 2017, to March 18, 2018. Between April 23, 2019, and Sept 13, 2019, community surveys were conducted in 50 randomly selected households per cluster; ten households per cluster were randomly selected for entomology surveys. Mosquitoes were collected in the morning from indoor surfaces of households using Prokopack aspirators. Due to COVID-19 restrictions, only 90 of the 104 clusters were surveyed at 25 months. The primary outcome was parasite prevalence by microscopy in children aged 2-10 years, assessed in the as-treated population, determined using the results from the 6-month household survey on the type of LLINs received in each cluster. This trial is registered with ISRCTN, ISRCTN17516395, and is now completed.In the as-treated analysis, two clusters were excluded (no predominant LLIN received) and four were reassigned; 40 PBO LLIN clusters (30 PermaNet 3.0, ten Olyset Plus) and 48 non-PBO LLIN (36 PermaNet 2.0, 12 Olyset Net) were included. Parasite prevalence was 17·1% (506 of 2958 participants) in the PBO group and 19·8% (701 of 3534) in the non-PBO group (prevalence ratio adjusted for baseline 0·80 [95% CI 0·69-0·93], p=0·0048). Comparing within-treatment group parasite prevalence to baseline, parasite prevalence ratios were lower in the PBO groups at all timepoints, but the difference was greatest at 6 months (PBO LLINs parasite prevalence at baseline 28·8% [1001 of 3472, 95% CI 27·3-30·4] vs at 6 months 12·0% [361 of 3009, 10·9-13·2], prevalence ratio [PR] 0·43 [95% CI 0·36-0·52], p<0·0001; non-PBO LLINs parasite prevalence at baseline 25·4% [1015 of 4004, 24·0-26·7] vs 6 months 14·8% [526 of 3551, 13·7-16·0], PR 0·60 [0·54-0·68], p<0·0001) and 25 months (PBO LLINs parasite prevalence at 25 months 17·1% [506 of 2958, 15·8-18·5], PR 0·63 [95% CI 0·57-0·71], p<0·0001; non-PBO LLINs parasite prevalence at 25 months 19·8% [701 of 3534, 18·5-21·2], PR 0·79 [0·73-0·86], p<0·0001).In Uganda, PBO LLINs outperformed pyrethroid-only LLINs for 25 months. WHO concluded that PBO LLINs are more effective against malaria than non-PBO LLINs when resistance to pyrethroids is high and issued a conditional recommendation suggesting PBO LLINs should be deployed in areas of pyrethroid resistance.The Against Malaria Foundation, UK Department for International Development, Innovative Vector Control Consortium, and Bill and Melinda Gates Foundation.

LLIN Evaluation in Uganda Project (LLINEUP) – The durability of long-lasting insecticidal nets treated with and without piperonyl butoxide (PBO) in Uganda

Abstract: Long Lasting Insecticidal Nets (LLINs) supplemented with the synergist piperonyl butoxide have been developed in response to growing pyrethroid resistance however their durability in the field remains poorly described. A pragmatic cluster-randomised trial was embedded into Uganda’s 2017-2018 distribution to compare the durability of LLINs with and without PBO A total of 104 clusters were included with each receiving one of four LLIN products, two with pyrethroid+PBO (Olyset Plus and PermaNet 3.0) and two pyrethroid-only (Olyset Net and PermaNet 2.0). Nets were sampled at baseline, 12, and 25 months post-distribution to assess physical condition, chemical content, and bioefficacy. Physical condition was quantified using proportionate Hole Index and chemical content measured using high-performance liquid chromatography. Bioefficacy was assessed with three-minute WHO Cone and Wireball assays using pyrethroid-resistant An. gambiae, with 1hr knockdown and 24hr mortality recorded. There was no difference in physical durability between LLIN products assessed (p=0.644). The pyrethroid content of all products remained relatively stable across timepoints but PBO content declined by 55% (p<0.001) and 58% (p<0.001) for Olyset Plus and PermaNet 3.0 respectively. Both PBO LLINs were highly effective against pyrethroid-resistant mosquitoes when new, knocking down all mosquitoes. However, bioefficacy declined over time with Olyset Plus knocking down 45.72% (95% CI: 22.84-68.62, p=0.021) and Permanet 3.0 knocking down 78.57% (95% CI: 63.57-93.58, p<0.001) after 25 months. Here we demonstrate that both Olyset Plus and PermaNet 3.0 are as durable as their pyrethroid-only equivalents and had superior bioefficacy against pyrethroid-resistant An. gambiae. However, the superiority of PBO-LLINs decreased with operational use, correlating with a reduction in total PBO content. This decline in bioefficacy after just two years is concerning and there is an urgent need to assess the durability of PBO LLINs in other settings.

House design and risk of malaria, acute respiratory infection and gastrointestinal illness in Uganda: A cohort study

Abstract: House construction is rapidly modernizing across Africa but the potential benefits for human health are poorly understood. We hypothesised that improvements to housing would be associated with reductions in malaria, acute respiratory infection (ARI) and gastrointestinal illness in an area of low malaria endemicity in Uganda. Data were analysed from a cohort study of male and female child and adult residents (n = 531) of 80 randomly-selected households in Nagongera sub-county, followed for 24 months (October 4, 2017 to October 31, 2019). Houses were classified as modern (brick walls, metal roof and closed eaves) or traditional (all other homes). Light trap collections of mosquitoes were done every two weeks in all sleeping rooms. Every four weeks, we measured malaria infection (using microscopy and qPCR to detect malaria parasites), incidence of malaria, ARI and gastrointestinal illness. We collected 15,780 adult female Anopheles over 7,631 nights. We collected 13,277 blood samples of which 10.2% (1,347) were positive for malaria parasites. Over 958 person years we diagnosed 38 episodes of uncomplicated malaria (incidence 0.04 episodes per person-year at risk), 2,553 episodes of ARI (incidence 2.7 episodes per person-year) and 387 episodes of gastrointestinal illness (incidence 0.4 episodes per person-year). Modern houses were associated with a 53% lower human biting rate compared to traditional houses (adjusted incidence rate ratio [aIRR] 0.47, 95% confidence interval [CI] 0.32–0.67, p<0.001) and a 24% lower incidence of gastrointestinal illness (aIRR 0.76, 95% CI 0.59–0.98, p = 0.04) but no changes in malaria prevalence, malaria incidence nor ARI incidence. House improvements may reduce mosquito-biting rates and gastrointestinal illness among children and adults. For the health sector to leverage Africa’s housing modernization, research is urgently needed to identify the healthiest house designs and to assess their effectiveness across a range of epidemiological settings in sub-Saharan Africa.

“I was still very young”: agency, stigma and HIV care strategies at school, baseline results of a qualitative study among youth in rural Kenya and Uganda

Abstract: Adolescents and young adults living with HIV (AYAH) have the lowest rates of retention in HIV care and antiretroviral therapy (ART) adherence, partly due to the demands of school associated with this life stage, to HIV‐related stigma and to fears of serostatus disclosure. We explore the implications of school‐based stigma and disclosure on the development of agency during a critical life stage in rural Kenya and Uganda.

Age-dependent changes in circulating Tfh cells influence development of functional malaria antibodies in children

Abstract: T-follicular helper (Tfh) cells are key drivers of antibodies that protect from malaria. However, little is known regarding the host and parasite factors that influence Tfh and functional antibody development. Here, we use samples from a large cross-sectional study of children residing in an area of high malaria transmission in Uganda to characterize Tfh cells and functional antibodies to multiple parasites stages. We identify a dramatic re-distribution of the Tfh cell compartment with age that is independent of malaria exposure, with Th2-Tfh cells predominating in early childhood, while Th1-Tfh cell gradually increase to adult levels over the first decade of life. Functional antibody acquisition is age-dependent and hierarchical acquired based on parasite stage, with merozoite responses followed by sporozoite and gametocyte antibodies. Antibodies are boosted in children with current infection, and are higher in females. The children with the very highest antibody levels have increased Tfh cell activation and proliferation, consistent with a key role of Tfh cells in antibody development. Together, these data reveal a complex relationship between the circulating Tfh compartment, antibody development and protection from malaria.

Two or more significant life-events in 6-months are associated with lower rates of HIV treatment and virologic suppression among youth with HIV in Uganda and Kenya

Abstract: ABSTRACT Youth living with HIV in sub-Saharan Africa have poor HIV care outcomes. We determined the association of recent significant life-events with HIV antiretroviral treatment (ART) initiation and HIV viral suppression in youth aged 15–24 years living with HIV in rural Kenya and Uganda. This was a cross-sectional analysis of 995 youth enrolled in the SEARCH Youth study. At baseline, providers assessed recent (within 6 months) life-events, defined as changes in schooling/employment, residence, partnerships, sickness, incarceration status, family strife or death, and birth/pregnancy, self-reported alcohol use, being a parent, and HIV-status disclosure. We examined the frequencies of events and their association with ART status and HIV viral suppression (<400 copies/ul). Recent significant life-events were prevalent (57.7%). Having >2 significant life-events (aOR = 0.61, 95% CI:0.45-0.85) and consuming alcohol (aOR = 0.61, 95% CI:0.43-0.87) were associated with a lower odds of HIV viral suppression, while disclosure of HIV-status to partner (aOR = 2.39, 95% CI:1.6-3.5) or to family (aOR = 1.86, 95% CI:1.3-2.7), being a parent (aOR = 1.8, 95% CI:1.2-2.5), and being single (aOR = 1.6, 95% CI:1.3-2.1) had a higher odds. This suggest that two or more recent life-events and alcohol use are key barriers to ART initiation and achievement of viral suppression among youth living with HIV in rural East Africa. Trial registration: ClinicalTrials.gov identifier: NCT03848728..

Genetic variation that determines TAPBP expression levels associates with the course of malaria in an HLA allotype-dependent manner

Abstract: Significance Peptides are selected and bound to HLA-I within the endoplasmic reticulum, aided by the molecular chaperone tapasin. HLA-I allotypes vary in their dependence on tapasin for peptide loading, and tapasin-independent allotypes present a more diverse set of peptides than tapasin-dependent allotypes. We show that imputed TAPBP messenger RNA-expression levels, along with HLA-I allotype-specific tapasin dependence level, associate with malaria outcome. High TAPBP expression significantly associated with protection amongst individuals with tapasin-dependent HLA allotypes relative to low tapasin expression. Tapasin expression had no effect on tapasin-independent allotypes, which conferred protection regardless of imputed tapasin-expression levels. Thus, intrinsically high tapasin-expression levels may compensate for the restrictive nature of HLA-I tapasin dependence in the peptide-loading process, attenuating the course of malaria.

Metagenomic next-generation sequencing to characterize etiologies of non-malarial fever in a cohort living in a high malaria burden area of Uganda

Abstract: Background: Causes of non-malarial fevers in sub-Saharan Africa remain understudied. We hypothesized that metagenomic next-generation sequencing (mNGS), which allows for broad genomic-level detection of infectious agents in a biological sample, can systematically identify potential causes of non-malarial fevers. Methods and Findings: The 212 participants in this study were of all ages and were enrolled in a longitudinal malaria cohort in eastern Uganda. Between December 2020 and August 2021, respiratory swabs and plasma samples were collected at 313 study visits where participants presented with fever and were negative for malaria by microscopy. Samples were analyzed using CZ ID, a web-based platform for microbial detection in mNGS data. Overall, viral pathogens were detected at 123 of 313 visits (39%). SARS-CoV-2 was detected at 11 visits, from which full viral genomes were recovered from nine. Other prevalent viruses included Influenza A (14 visits), RSV (12 visits), and three of the four strains of seasonal coronaviruses (6 visits). Notably, 11 influenza cases occurred between May and July 2021, coinciding with when the Delta variant of SARS-CoV-2 was circulating in this population. The primary limitation of this study is that we were unable to estimate the contribution of bacterial microbes to non-malarial fevers, due to the difficulty of distinguishing bacterial microbes that were pathogenic from those that were commensal or contaminants. Conclusions: These results revealed the co-circulation of multiple viral pathogens likely associated with fever in the cohort during this time period. This study illustrates the utility of mNGS in elucidating the multiple causes of non-malarial febrile illness. A better understanding of the pathogen landscape in different settings and age groups could aid in informing diagnostics, case management, and public health surveillance systems.

Reconstructing the SARS-CoV-2 epidemic in eastern Uganda through longitudinal serosurveillance in a malaria cohort

Abstract: ABSTRACT Importance: Estimating the true burden of SARS-CoV-2 infection has been difficult in sub-Saharan Africa due to asymptomatic infections and inadequate testing capacity. Antibody responses from serologic surveys can provide an estimate of SARS-CoV-2 exposure at the population level. Objective: To estimate SARS-CoV-2 seroprevalence, attack rates, and re-infection in eastern Uganda using serologic surveillance from 2020 to early 2022. Design: Plasma samples from participants in the Program for Resistance, Immunology, Surveillance, and Modeling of Malaria in Uganda (PRISM) Border Cohort were obtained at four sampling intervals: October-November 2020; March-April 2021; August-September 2021; and February-March 2022. Setting: Tororo and Busia districts, Uganda. Participants: 1,483 samples from 441 participants living in 76 households were tested. Each participant contributed up to 4 time points for SARS-CoV-2 serology, with almost half of all participants contributing at all 4 time points, and almost 90% contributing at 3 or 4 time points. Information on SARS-CoV-2 vaccination status was collected from participants, with the earliest reported vaccinations in the cohort occurring in May 2021. Main Outcome(s) and Measure(s): The main outcomes of this study were antibody responses to the SARS-CoV-2 spike protein as measured with a bead-based serologic assay. Individual-level outcomes were aggregated to population-level SARS-CoV-2 seroprevalence, attack rates, and boosting rates. Estimates were weighted by the local age distribution based on census data. Results: By the end of the Delta wave and before widespread vaccination, nearly 70% of the study population had experienced SARS-CoV-2 infection. During the subsequent Omicron wave, 85% of unvaccinated, previously seronegative individuals were infected for the first time, and ~50% or more of unvaccinated, already seropositive individuals were likely re-infected, leading to an overall 96% seropositivity in this population. Our results suggest a lower probability of re-infection in individuals with higher pre-existing antibody levels. We found evidence of household clustering of SARS-CoV-2 seroconversion. We found no significant associations between SARS-CoV-2 seroconversion and gender, household size, or recent Plasmodium falciparum malaria exposure. Conclusions and Relevance: Findings from this study are consistent with very high infection rates and re-infection rates for SARS-CoV-2 in a rural population from eastern Uganda throughout the pandemic.

Providers' Attitudes and Experiences with Pre-Exposure Prophylaxis Implementation in a Population-Based Study in Kenya and Uganda.

Abstract: Pre-exposure prophylaxis (PrEP) implementation is underway across sub-Saharan Africa. However, little is known about health care providers' experiences with PrEP provision in generalized epidemic settings, particularly outside of selected risk groups. In this study (NCT01864603), universal access to PrEP was offered to adolescents and adults at elevated risk during population-level HIV testing in rural Kenya and Uganda. Providers received training on PrEP prescribing and support from local senior clinicians. We conducted in-depth interviews with providers (n = 19) in four communities in Kenya and Uganda to explore the attitudes and experiences with implementation. Transcripts were coded and analyzed using interpretivist methods. Providers had heterogenous attitudes toward PrEP in its early implementation: some expressed enthusiasm, while others feared being blamed for "failures" (HIV seroconversions) if participants were nonadherent, or that offering PrEP would increase "immorality." Providers supported PrEP usage among HIV-serodifferent couples, whose mutual support for daily pill-taking facilitated harmony and protection from HIV. Providers reported challenges with counseling on "seasons of risk," and safely stopping and restarting PrEP. They felt uptake was hampered for women by difficulties negotiating with partners, and for youth by parental consent requirements. They believed PrEP continuation was hindered by transportation costs, stigma, pill burden, and side effects, and was facilitated by counseling, proactive management of side effects, and home/community-based provision. Providers are critical "implementation actors" in interventions to promote adoption of new technologies such as PrEP. Dedicated training and ongoing support for providers may facilitate successful scale-up.

PEP for HIV prevention: are we missing opportunities to reduce new infections?

Abstract: There is newfound optimism for global efforts to reduce the estimated 1.7 million new HIV infections still occurring every year with expanded pre-exposure prophylaxis (PrEP) access and newer biomedical prevention options on the horizon [1]. The increasing range of antiretroviral-based prevention options, such as the dapivirine ring and long-acting cabotegravir, move the concept of personal “choice” between biomedical HIV prevention options from the theoretical to the actual [2]. Post-exposure prophylaxis (PEP) is not a new option for prevention in adults, but it is one that has been underutilized for decades in lowand middle-income settings, largely being reserved only for high-risk occupational exposures among healthcare workers. We challenge this approach. The arguments to expand PEP access beyond occupational exposure are three-fold. First, PEP is the only prevention option for adults that can be started after (vs. before) a highrisk exposure. Based on human data and animal models, PEP works after needle stick or sexual exposure and needs to be started within 72 hours [3]. HIV risk exposures are often neither planned nor anticipated. Further, risk is dynamic and varies over time for each individual. Second, PEP using currently recommended integrase strand transfer inhibitor-based regimens is well-tolerated and can be delivered outside of occupational exposure settings, including in settings, such as rural sub-Saharan Africa (SSA), when operational barriers are addressed [4]. Estimated PEP efficacy is over 90%, which exceeds that of some other prevention options, such as the dapivirine ring [2]. PEP is particularly appealing due to the relatively short period of adherence required (i.e. for a 28-day course). It effectively covers onetime high-risk exposures even among known high-risk groups that do not have continuous ongoing risk, or those who opt to take a “break” from PrEP due to daily pill fatigue. When we offered PEP to persons with high-risk sexual exposures in rural Kenya and Uganda using a patient-centred approach that included offering services outside government clinics, 85% completed the 28-day course and follow-up testing. PEP was well tolerated, and there were no HIV seroconversions. Patients reported high satisfaction having an option that did not require ongoing daily medication [5]. Finally, PEP can be both a gateway to other prevention options for persons with ongoing exposure or a bridge for persons who have needs for short-term protection, inclusive but not limited to occupational exposures [6]. Persons who access PEP have the opportunity to hear about other prevention options, such as PrEP. If they have ongoing risk, they can transition to PrEP with adherence support to overcome the challenge of taking a daily medication. We have found that some clients opt for repeated PEP and then make the self-assessment that they would prefer to be on continuous PrEP only after this experience. We should both expect and embrace different on-ramps and off-ramps for HIV prevention options. PEP can overcome some, but not all of the challenges of daily oral PrEP. Any daily oral pill started after a sexual encounter or needle sharing can be associated with stigma that can discourage the use of a preventive intervention even if the treatment requires only 28 days [7]. The similarity of PEP to HIV treatment can itself produce stigma of HIV infection that discourages uptake. Just like PrEP, persons can have side effects that make them unwilling to adhere to the regimen. All prevention options need to start with health literacy. Consumer education needs to expand beyond mere knowledge of options available and their side effects. It should include understanding patient goals and application of the knowledge in making choices of appropriate options to match their context [8]. If PEP requires no preplanning, is effective and requires only a short-term 28-day commitment and can potentially increase access to other biomedical options, such as PrEP, then why is it not more widely used? Guidelines per se are not the obstacle. In 2014, the World Health Organization expanded the recommendation for PEP for all persons who have occasional, unanticipated high-risk exposure [9]. Drug supply also does not appear to be the major obstacle now that PEP regimens are the same as first-line Anti-Retroviral Therapy (ART) treatment regimens. Reasons for low uptake appear multi-faceted and vary across settings. Despite being aware of PEP, men-who-have-sex with-men face barriers to access and use of PEP in Africa [10, 11]. Across multiple geographic

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.

Abstract: 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 at 24 and 36 months of age. RESULTS Children of mothers with vs. 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.

Distinct forms of migration and mobility are differentially associated with HIV treatment adherence

Abstract: Objective: We examined whether human mobility was associated with antiretroviral treatment adherence, measured via antiretroviral hair concentrations. Design: This is a cross-sectional analysis of adults on antiretroviral treatment in East Africa at baseline in an observational cohort study. Methods: Participants reported recent mobility (overnight travel) and histories of migration (changes of residence), including reasons, frequency/duration, and locations. Hair antiretroviral concentrations were analyzed using validated methods. We estimated associations between mobility and antiretroviral concentrations via linear regression adjusted for age, sex, region, years on treatment. Results: Among 383 participants, half were women and the median age was 40. Among men, 25% reported recent work-related mobility, 30% nonwork mobility, and 11% migrated in the past year (mostly across district boundaries); among women, 6 and 57% reported work-related and nonwork mobility, respectively, and 8% recently migrated (mostly within district). Those reporting work-related trips 2 nights or less had 72% higher hair antiretroviral levels (P = 0.02) than those who did not travel for work; in contrast, nonwork mobility (any duration, vs. none) was associated with 24% lower levels (P = 0.06). Intra-district migrations were associated with 59% lower antiretroviral levels than nonmigrants (P = 0.003) while inter-district migrations were not (27% higher, P = 0.40). Conclusion: We found that localized/intra-district migration and nonwork travel—more common among women—were associated with lower adherence, potentially reflecting care interruptions or staying with family/friends unaware of the participants’ status. In contrast, short work-related trips—more common among men—were associated with higher adherence, perhaps reflecting higher income. Adherence interventions may require tailoring by sex and forms of mobility.

Gametocyte production in incident P. falciparum infections: a longitudinal study in a low transmission setting under intensive vector control

Abstract: Malaria transmission depends on the presence of Plasmodium gametocytes that are the only parasite life stage that can infect mosquitoes. Gametocyte production varies between infections and over the course of infections. Infection duration is influenced by host and parasite characteristics, and is highly important for gametocyte production but poorly quantified. Between 2017-2019 an all-age cohort from Tororo, eastern Uganda was followed by continuous passive and routine assessments. Among 104 longitudinally monitored incident infections coming from 98 individuals, we observed that nearly all infections lasting 3 or more months initiated gametocyte production prior to clearance. However, the majority of infections were of shorter duration (<28 days) and were cleared before gametocytes were detectable. Infections in individuals with sickle-cell trait were more likely to produce gametocytes and produced gametocytes at higher densities. Our findings suggest that a large proportion of infections may be too short in duration and of too low density to contribute to onward transmission.

Effect of a one-time financial incentive on linkage to chronic hypertension care in Kenya and Uganda: A randomized controlled trial

Abstract: Background Fewer than 10% of people with hypertension in sub-Saharan Africa are diagnosed, linked to care, and achieve hypertension control. We hypothesized that a one-time financial incentive and phone call reminder for missed appointments would increase linkage to hypertension care following community-based screening in rural Uganda and Kenya. Methods In a randomized controlled trial, we conducted community-based hypertension screening and enrolled adults ≥25 years with blood pressure ≥140/90 mmHg on three measures; we excluded participants with known hypertension or hypertensive emergency. The intervention was transportation reimbursement upon linkage (~$5 USD) and up to three reminder phone calls for those not linking within seven days. Control participants received a clinic referral only. Outcomes were linkage to hypertension care within 30 days (primary) and hypertension control <140/90 mmHg measured in all participants at 90 days (secondary). We used targeted minimum loss-based estimation to compute adjusted risk ratios (aRR). Results We screened 1,998 participants, identifying 370 (18.5%) with uncontrolled hypertension and enrolling 199 (100 control, 99 intervention). Reasons for non-enrollment included prior hypertension diagnosis (n = 108) and hypertensive emergency (n = 32). Participants were 60% female, median age 56 (range 27–99); 10% were HIV-positive and 42% had baseline blood pressure ≥160/100 mmHg. Linkage to care within 30 days was 96% in intervention and 66% in control (aRR 1.45, 95%CI 1.25–1.68). Hypertension control at 90 days was 51% intervention and 41% control (aRR 1.22, 95%CI 0.92–1.66). Conclusion A one-time financial incentive and reminder call for missed visits resulted in a 30% absolute increase in linkage to hypertension care following community-based screening. Financial incentives can improve the critical step of linkage to care for people newly diagnosed with hypertension in the community.

The Association Between Social Network Characteristics and Tuberculosis Infection Among Adults in Nine Rural Ugandan Communities.

Abstract: BACKGROUND Social network analysis can elucidate Tuberculosis (TB) transmission dynamics outside of the home and may inform novel network-based case-finding strategies. METHODS We assessed the association between social network characteristics and prevalent TB infection among residents (≥15 years) of 9 rural communities in Eastern Uganda. Social contacts named during a census were used to create community-specific non-household social networks. We evaluated whether social network structure and characteristics of first-degree contacts (gender, HIV status, TB infection) were associated with prevalent TB infection (positive TST) after adjusting for individual-level risk factors (age, gender, HIV status, TB contact, wealth, occupation, and BCG vaccination) with Targeted Maximum Likelihood Estimation. RESULTS Among 3,335 residents sampled for TST, 32% had a positive TST, 4% reported a TB contact. The social network contained 15,328 first-degree contacts. Persons with the most network centrality (top 10%) (aRR: 1.3 (1.1-1.1) and the most (top 10%) male contacts (aRR: 1.5 (95% CI: 1.3-1.9) had a higher risk of prevalent TB, compared to those in the remaining 90%. People with ≥1 contacts with HIV (aRR 1.3; 95% CI:1.1-1.6) and ≥2 contacts with TB infection were more likely to themselves have TB (aRR: 2.6; 95% CI: 2.2-2.9). CONCLUSIONS Social networks with higher centrality, more men, contacts with HIV, and TB infection, were positively associated with TB infection. TB transmission within measurable social networks may explain prevalent TB not associated with a household contact. Further study on network-informed TB case finding interventions is warranted.

Impact of different mosquito collection methods on indicators of Anopheles malaria vectors in Uganda

Abstract: Abstract Background Methods used to sample mosquitoes are important to consider when estimating entomologic metrics. Human landing catches (HLCs) are considered the gold standard for collecting malaria vectors. However, HLCs are labour intensive, can expose collectors to transmission risk, and are difficult to implement at scale. This study compared alternative methods to HLCs for collecting Anopheles mosquitoes in eastern Uganda. Methods Between June and November 2021, mosquitoes were collected from randomly selected households in three parishes in Tororo and Busia districts. Mosquitoes were collected indoors and outdoors using HLCs in 16 households every 4 weeks. Additional collections were done indoors with prokopack aspirators, and outdoors with pit traps, in these 16 households every 2 weeks. CDC light trap collections were done indoors in 80 households every 4 weeks. Female Anopheles mosquitoes were identified morphologically and Anopheles gambiae sensu lato were speciated using PCR. Plasmodium falciparum sporozoite testing was done with ELISA. Results Overall, 4,891 female Anopheles were collected, including 3,318 indoors and 1,573 outdoors. Compared to indoor HLCs, vector density (mosquitoes per unit collection) was lower using CDC light traps (4.24 vs 2.96, density ratio [DR] 0.70, 95% CIs 0.63–0.77, p < 0.001) and prokopacks (4.24 vs 1.82, DR 0.43, 95% CIs 0.37–0.49, p < 0.001). Sporozoite rates were similar between indoor methods, although precision was limited. Compared to outdoor HLCs, vector density was higher using pit trap collections (3.53 vs 6.43, DR 1.82, 95% CIs 1.61–2.05, p < 0.001), while the sporozoite rate was lower (0.018 vs 0.004, rate ratio [RR] 0.23, 95% CIs 0.07–0.75, p = 0.008). Prokopacks collected a higher proportion of Anopheles funestus (75.0%) than indoor HLCs (25.8%), while pit traps collected a higher proportion of Anopheles arabiensis (84.3%) than outdoor HLCs (36.9%). Conclusion In this setting, the density and species of mosquitoes collected with alternative methods varied, reflecting the feeding and resting characteristics of the common vectors and the different collection approaches. These differences could impact on the accuracy of entomological indicators and estimates of malaria transmission, when using the alternative methods for sampling mosquitos, as compared to HLCs.