Results
- Showing results for:
- Reset all filters
Search results
-
Journal articleAlexander N, Dye C, Busch MP, et al., 2025,
Dynamics of SARS-CoV-2 infection over two epidemic waves in Manaus, Brazil: A serological study of seven thousand blood donors.
, PLoS One, Vol: 20BACKGROUND: Most longitudinal studies of COVID-19 incidence have used unlinked samples. The city of Manaus, Brazil, has a blood donation program which allows sample linkage, and was struck by two large COVID-19 epidemic waves between mid-2020 and early 2021. METHODS: We estimated the changing force of infection, i.e. incidence in susceptible individuals. Seroconversion was inferred by a mixture model for serial values from the Abbott Architect SARS-CoV-2 nucleocapsid (N) IgG assay. We estimated the number of suspected COVID-19 hospitalizations arising from each infection over calendar time. RESULTS: Whole blood donations between April 2020 and March 2021 were included from 6734 people, 2747 with two or more donations. The inferred criterion for seroconversion, and thus an incident infection, was a 6.07 fold increase in N IgG reactivity. The overall force of infection was 1.19 per person year (95% confidence interval 1.14-1.24) during the two main waves. The estimated number of suspected hospitalizations per infection, was approximately 4.1 times higher in the second wave than in the first. CONCLUSIONS: Serial values from this assay can be used to infer seroconversion over time, and in Manaus show a higher number of suspected COVID-19 hospitalizations per infection in the second wave relative to the first.
-
Journal articleMoghaddas NR, Traore MM, Müller GC, et al., 2025,
Exploring the epidemiological impact of attractive targeted sugar bait against malaria in combination with standard malaria control.
, Curr Res Parasitol Vector Borne Dis, Vol: 7Attractive targeted sugar bait (ATSB) is a potential new vector control tool that exploits the sugar-feeding behaviour of mosquitoes. Little is known about the factors which drive ATSB efficacy, either as a standalone vector control tool or in combination with existing intervention strategies. It has been suggested that the percentage of wild mosquitoes caught fed on dye-containing sugar baits without the toxin could provide an entomological correlate of the potential epidemiological benefit of ATSB. A transmission dynamics mathematical model is combined with data from wild mosquitoes to investigate the relationship between the mosquito dyed fraction, bait-feeding rate and the potential epidemiological impact of ATSB in the presence of standard malaria control. The dyed fraction in Mali varies substantially in space and time (mean 0.34, standard deviation 0.15), causing estimates of the bait-feeding rate to be highly uncertain, especially in areas with existing vector control tools. The model indicates the dyed fractions observed in field experiments were broadly predictive of the reductions in mosquitoes caught when ATSB stations were deployed at scale in Mali (R 2 = 0.90). Model projections suggest that if these bait-feeding rates were observed in all mosquitoes, then the widespread use of ATSB could substantially reduce malaria burden alone or in combinations with standard malaria control, though epidemiological impact is likely to vary substantially in different areas. For example, observing a dyed fraction of 5% would indicate a daily bait-feeding rate of 0.024 (range 0.008-0.049) which is projected to result in 0.13 clinical cases averted per person-year (range 0.051-0.22), a 39% efficacy (range 12-66%) in this particular site. Nevertheless, the uncertainty in the relationship between the observed dyed fraction and the true bait-feeding rate, and the underlying biology of mosquito sugar-feeding means that the epidemiological benefit of this new possi
-
Journal articleOwusu M, Darko E, Akortia D, et al., 2025,
Evaluation of Moore and grab sampling method for Salmonella Typhi detection in environmental samples in Ghana.
, PLoS One, Vol: 20BACKGROUND: Typhoid fever causes substantial mortality and morbidity in low and middle-income countries (LMICs) as a result of inadequate water, hygiene, and sanitation facilities. The gold standard for typhoid diagnosis is blood culture, however this method is expensive and mostly unavailable in LMICs. Environmental surveillance (ES) could offer a low cost alternative to identify circulation of Salmonella enterica serovar Typhi (S.Typhi) and help inform public health interventions including vaccination. METHODS: We implemented standardized protocols for ES at 40 validated sites in peri-urban communities in Ghana from July 2022 to August 2023. Grab samples (GS) and Moore swabs (MS) were collected monthly for the initial 6 months and subsequently monthly MS were maintained for the rest of the study period. Wastewater samples were tested for S. Typhi target genes (ttr, staG, tviB) and a biomarker of human faecal contamination (Bacteroides HF183) using multiplex quantitative PCR (qPCR). Clinical surveillance for typhoid fever was performed by blood culture of febrile cases presenting to the local hospital who lived in the study area. RESULTS: For the first 6 months of wastewater ES, we observed a higher prevalence of S. Typhi in MS compared to GS [100/240 (42%; 95% Confidence Interval [CI]: 34-50% vs. 24/240 (10%; 95% CI: 6-16%)]; p-value < 0.001]. Overall, the detection of S. Typhi throughout the study period based on MS was 42.1% (202/480; 95% CI: 35-50%). The prevalence of S. Typhi in blood culture surveillance was 0.21% [12/5,576; 95% CI: 0.12-0.38%]. Precipitation (1.1 (95% CI: 1.02-1.10) and number of wet days (2.0 (95%CI: 1.40-2.88) were positively associated with an increased odds of S. Typhi detection in MS and GS. CONCLUSION: Generally the proportion of S.Typhi detections in wastewater samples was less than blood culture-based detections. Limited detection of confirmed typhoid fever cases at the local hospital may reflect healthcare seeking behaviours, acc
-
Journal articlePaschoalotto MAC, Cima J, Costa E, et al., 2024,
Politics and confidence toward the COVID-19 vaccination: A Brazilian cross-sectional study.
, Hum Vaccin Immunother, Vol: 20This study has the aim of assessing the Brazilian perceptions, influencing factors and political positioning on the confidence concerning COVID-19 vaccination. To achieve the objective, the methods rely on a cross-sectional survey of Brazilian citizens, distributed through different social networks. The sample is composed of 1,670 valid responses, collected from almost all Brazilian states and state capitals. To analyze the data and give a clear view of the variables' relationship, the study used bivariate and comparative graphs. Results show a higher level of confidence in vaccines from Pfizer and AstraZeneca, while the lower level of confidence is associated with vaccines from Sinopharm and Sputinik5. Vaccine efficacy is the most significant influencing factor that helps in the decision to get vaccinated. Also, individuals are less willing to get vaccinated if their political preferences are related to the right-wing. The results led to three main health and social implications: i) the vaccination strategy campaigns should take in count vaccine efficacy and political aspects; ii) the vaccination process should be adapted to regions with different political positions; and iii) a reinforcement in the educational policies of the vaccine's importance to the public health, to avoid the politization of a health issue.
-
Journal articleMonteirinho Leitao RA, Leitao R, Wan IU, et al., 2024,
Detection of fungal sequences in human brain: rDNA locus amplification and deep sequencing
, Scientific Reports, Vol: 14, ISSN: 2045-2322The aetiology of Alzheimer’s disease (AD) and Parkinson’s disease (PD) are unknown and tend to manifest at a late stage in life; even though these neurodegenerative diseases are caused by different affected proteins, they are both characterized by neuroinflammation. Links between bacterial and viral infection and AD/PD has been suggested in several studies, however, few have attempted to establish a link between fungal infection and AD/PD. In this study we adopted a nanopore-based sequencing approach to characterise the presence or absence of fungal genera in both human brain tissue and cerebrospinal fluid (CSF). We observed the presence of small fungal burden DNA in two AD brains and a control case (extensive amyloid angiopathy). This approach would be well-placed to investigate potential links between microbial infection and neurodegenerative disease.
-
Journal articleDenkel LA, Arnaud I, Brekelmans M, et al., 2024,
Automated surveillance for surgical site infections (SSI) in hospitals and surveillance networks-expert perspectives for implementation.
, Antimicrob Resist Infect Control, Vol: 13BACKGROUND: This work aims at providing practical recommendations for implementing automated surveillance (AS) of surgical site infections (SSI) in hospitals and surveillance networks. It also provides an overview of the steps, choices, and obstacles that need to be taken into consideration when implementing such surveillance. Hands-on experience with existing automated surveillance systems of SSI (AS SSI systems) in Denmark, France, the Netherlands and Spain is described regarding trend monitoring, benchmarking, quality control, and research for surveillance purposes. METHODS: Between April and October 2023, specific aspects/options of various surveillance purposes for AS SSI were identified during regular meetings of the SSI working group in the PRAISE (Providing a Roadmap for Automated Infection Surveillance in Europe) network. Expert discussions provided the basis for this perspective article. RESULTS: Decisions for implementation of AS SSI systems highly depend on the purpose of the surveillance. AS SSI systems presented here differ according to study population, setting, central or local implementation; the level of automation, design, and the data sources used. However, similarities were found for the rationales of automation, design principles and obstacles that were identified. There was consensus among all the experts that shortcomings in interoperability of databases, limited time, a want of commitment on the part of stakeholders, and a shortage of resources for information technology (IT) specialists represent the main obstacles for implementing AS SSI. To overcome obstacles, various solutions were reported, including training in the development of AS systems and the interpretation of AS SSI results, early consultation of end-users, and regular exchanges between management levels, IT departments, infection prevention and control (IPC) teams, and clinicians. CONCLUSION: Clarity on the intended application (e.g. purpose of surveillance) and information on
-
Journal articleAgbevo A, Syme T, Fagbohoun J, et al., 2024,
The experimental hut efficacy of next-generation insecticide-treated nets against pyrethroid-resistant malaria vectors after 12, 24 and 36 months of household use in Benin
, MALARIA JOURNAL, Vol: 23 -
Journal articleMichalow J, Hall L, Rowley J, et al., 2024,
Prevalence of chlamydia, gonorrhoea, and trichomoniasis among male and female general populations in sub-Saharan Africa from 2000-2024: A systematic review and meta-regression analysis.
, medRxivBACKGROUND: Sub-Saharan Africa (SSA) has the highest sexually transmitted infection (STI) prevalence globally, but information about trends and geographic variation is limited by sparse aetiologic studies, particularly among men. This systematic review assessed chlamydia, gonorrhoea, and trichomoniasis prevalence by sex, sub-region, and year, and estimated male-to-female prevalence ratios for SSA. METHODS: We searched Embase, MEDLINE, Global Health, PubMed, and African Index Medicus for studies measuring STI prevalence among general populations from January 1, 2000, to September 17, 2024. We adjusted observations for diagnostic test performance and used log-binomial mixed-effects meta-regressions to estimate prevalence trends and sex-prevalence ratios. FINDINGS: Of 5202 records identified, we included 211 studies from 28 countries. In 2020, estimated prevalence among 15-49-year-olds in SSA for chlamydia was 6.6% (95%CI: 5.0-8.2%, n=169 observations) among females and 4.7% (3.4-6.1%, n=33) among males, gonorrhoea was 2.4% (1.4-3.3%, n=171) and 1.7% (0.7-2.6%, n=31), and trichomoniasis was 6.8% (3.6-9.9%, n=188) and 1.7% (0.7-2.7%, n=19). Male-to-female ratio estimates were 0.61 (0.53-0.71) for chlamydia, 0.81 (0.61-1.09) for gonorrhoea, and 0.23 (0.18-0.28) for trichomoniasis. From 2010-2020, chlamydia prevalence increased by 34.5% (11.1-62.9%) in SSA, while gonorrhoea and trichomoniasis trends were not statistically significant. Chlamydia and gonorrhoea prevalence were highest in Southern and Eastern Africa, whereas trichomoniasis was similar across sub-regions. INTERPRETATION: SSA has a high, geographically varied STI burden, with increasing prevalence of chlamydia. Region-specific sex-prevalence ratios differed from existing global ratios and should be considered in future burden estimates. Enhanced sex-stratified surveillance is crucial to guide national programmes and reduce STI prevalence in SSA. FUNDING: Gates Foundation, Imperial College London, NIH, UKRI.
-
Journal articleBottery MJ, van Rhijn N, Chown H, et al., 2024,
Elevated mutation rates in multi-azole resistant <i>Aspergillus fumigatus</i> drive rapid evolution of antifungal resistance
, NATURE COMMUNICATIONS, Vol: 15 -
Journal articleWalters M, Korenromp E, Yakusik A, et al., 2024,
Guidance for triangulating data and estimates of HIV prevalence among pregnant women and coverage of PMTCT using the Spectrum AIDS Impact Module
, JAIDS: Journal of Acquired Immune Deficiency Syndromes, Vol: 97, Pages: 439-449, ISSN: 1525-4135Background: Most countries use the Spectrum AIDS Impact Module (Spectrum-AIM), antenatal care routine HIV testing, and antiretroviral treatment data to estimate HIV prevalence among pregnant women. Non-representative programme data may lead to inaccurate estimates HIV prevalence and treatment coverage for pregnant women. Setting: 154 countries and subnational locations across 126 countries.Methods: Using 2023 UNAIDS HIV estimates, we calculated three ratios: (1) HIV prevalence among pregnant women to all women 15-49y (prevalence), (2) ART coverage before pregnancy to women 15-49y ART coverage (ART pre-pregnancy), and (3) ART coverage at delivery to women 15-49y ART coverage (PMTCT coverage). We developed an algorithm to identify and adjust inconsistent results within regional ranges in Spectrum-AIM, illustrated using Burkina Faso’s estimates.Results: In 2022, the mean regional ratio of prevalence among pregnant women to all women ranged from 0.68 to 0.95. ART coverage pre-pregnancy ranged by region from 0.40 to 1.22 times ART coverage among all women. Mean regional PMTCT coverage ratios ranged from 0.85 to 1.51. The prevalence ratio in Burkina Faso was 1.59, above the typical range 0.62-1.04 in western and central Africa. Antenatal clinics reported more PMTCT recipients than estimated HIV-positive pregnant women from 2015 to 2019. We adjusted inputted PMTCT programme data to enable consistency of HIV prevalence among pregnant women from programmatic routine HIV testing at antenatal clinics with values typical for Western and central Africa. Conclusion: These ratios offer Spectrum-AIM users a tool to gauge the consistency of their HIV prevalence and treatment coverage estimates among pregnant women with other countries in the region.
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.
Contact us
For any enquiries related to the MRC Centre please contact:
Scientific Manager
Susannah Fisher
mrc.gida@imperial.ac.uk
External Relationships and Communications Manager
Dr Sabine van Elsland
s.van-elsland@imperial.ac.uk