Naïma Hammami - Academia.edu (original) (raw)

Papers by Naïma Hammami

Eurosurveillance

Since 2022, European countries have been facing an outbreak of mainly cutaneous diphtheria caused... more Since 2022, European countries have been facing an outbreak of mainly cutaneous diphtheria caused by toxigenic Corynebacterium diphtheriae among asylum seekers. In Belgium, between 1 March and 31 December 2022, 25 cases of toxigenic C. diphtheriae infection were confirmed among asylum seekers, mostly among young males from Afghanistan. Multi-locus sequence typing showed that most isolates belonged to sequence types 574 or 377, similar to the majority of cases in other European countries. The investigation and management of the outbreak, with many asylum seekers without shelter, required adjustments to case finding, contact tracing and treatment procedures. A test-and-treat centre was organised by non-governmental organisations, the duration of the antimicrobial treatment was shortened to increase compliance, and isolation and contact tracing of cases was not possible. A vaccination centre was opened, and mobile vaccination campaigns were organised to vaccinate a maximum of asylum se...

Infection Control and Hospital Epidemiology, May 12, 2021

Background: Hospital-acquired bloodstream infections (HABSIs) cause increased morbidity, mortalit... more Background: Hospital-acquired bloodstream infections (HABSIs) cause increased morbidity, mortality, and hospital costs that are partially preventable. HABSI seasonality has been described for gram-negative bacteria but has not been stratified per infection origin. Objective: To assess seasonality among all types of HABSIs and their associations with climate. Methods: Hospitals performing surveillance for at least 1 full calendar year between 2000 and 2014 were included. Mixed-effects negative binomial regression analysis calculated the peak-to-low monthly ratio as an adjusted HABSI incidence rate ratio (IRR) with 95% confidence intervals (CIs). Another regression model examined associations between HABSI rates and climate variables. These analyses were stratified by microorganism and infectious origin. Results: The study population included 104 hospitals comprising 44,111 HABSIs. Regression analysis identified an incidence rate ratio (IRR)

Journal of Antimicrobial Chemotherapy, Oct 21, 2021

Shigella sonnei resistant to first-line antibiotics azithromycin and ciprofloxacin are on the ris... more Shigella sonnei resistant to first-line antibiotics azithromycin and ciprofloxacin are on the rise globally. The aim of this study was to describe the epidemiology of MDR S. sonnei in Belgium and to identify origins and circulating clusters through WGS.

medRxiv (Cold Spring Harbor Laboratory), Oct 6, 2022

Background Contact tracing aims to prevent onward transmission of infectious diseases and data ob... more Background Contact tracing aims to prevent onward transmission of infectious diseases and data obtained during tracing provide unique information on transmission characteristics. A key performance indicator that has been proposed to evaluate contact tracing is the proportion of cases arising from known contacts. However, few empirical studies have investigated the effectiveness of contact tracing. Methods Using data collected between September 2020 and December 2021 in Belgium, we investigated the impact of contact tracing on SARS-CoV-2 transmission. We compared confirmed cases that were previously identified as a close contact to those that were not yet known, in terms of their traced contacts and secondary cases as well as the serial interval. In addition, we established contact and transmission patterns by age. Findings Previously traced, hence 'known', cases comprised 20% of all cases and they were linked to relatively fewer close contacts as well as fewer secondary cases and a lower secondary attack rate compared to cases that were not already known. In addition we observed a shorter serial interval for 'known' cases. There was a relative increase in transmission from children to adults during circulation of the Delta and Omicron variants, without an increase in the extent of contact between these age groups. Interpretation These results suggest that contact tracing in Belgium has been effective in reducing onward transmission and that individuals aware of their exposure to SARS-CoV-2 seemed more reserved in their social contact behaviour. Data from a reference period or region are needed to measure the impact of contact tracing in terms of the number of cases and deaths averted. 1 .

Sexually Transmitted Infections, Nov 17, 2022

Archives of public health, Jan 29, 2022

Background: In Belgium, the first COVID-19 death was reported on 10 March 2020. Nursing home (NH)... more Background: In Belgium, the first COVID-19 death was reported on 10 March 2020. Nursing home (NH) residents are particularly vulnerable for COVID-19, making it essential to follow-up the spread of COVID-19 in this setting. This manuscript describes the methodology of surveillance and epidemiology of COVID-19 cases, hospitalizations and deaths in Belgian NHs. Methods: A COVID-19 surveillance in all Belgian NHs (n = 1542) was set up by the regional health authorities and Sciensano. Aggregated data on possible/confirmed COVID-19 cases and hospitalizations and case-based data on deaths were reported by NHs at least once a week. The study period covered April-December 2020. Weekly incidence/prevalence data were calculated per 1000 residents or staff members. Results: This surveillance has been launched within 14 days after the first COVID-19 death in Belgium. Automatic data cleaning was installed using different validation rules. More than 99% of NHs participated at least once, with a median weekly participation rate of 95%. The cumulative incidence of possible/confirmed COVID-19 cases among residents was 206/1000 in the first wave and 367/1000 in the second wave. Most NHs (82%) reported cases in both waves and 74% registered ≥10 possible/confirmed cases among residents at one point in time. In 51% of NHs, at least 10% of staff was absent due to COVID-19 at one point. Between 11 March 2020 and 3 January 2021, 11,329 COVID-19 deaths among NH residents were reported, comprising 57% of all COVID-19 deaths in Belgium in that period.

Infection Control and Hospital Epidemiology, Apr 23, 2019

The epidemiology of hospital-acquired bloodstream infections (HABSIs) based on the Belgian nation... more The epidemiology of hospital-acquired bloodstream infections (HABSIs) based on the Belgian national surveillance program was analyzed (2000-2014). Our mixed-effects regression analysis identified increased rates of Escherichia coli, Klebsiella pneumoniae, and Enterococcus faecium. HABSI incidence and resistance patterns should be further monitored because of their impact on proper empiric antibiotic therapy.

Scientific Reports, Mar 25, 2022

Central line-associated bloodstream infections (CLABSI) cause increased morbidity, mortality, and... more Central line-associated bloodstream infections (CLABSI) cause increased morbidity, mortality, and hospital costs that are partially preventable. The phenomenon of seasonality among CLABSI rates has not been fully elucidated, but has implications for accurate surveillance and infection prevention trials. Longitudinal dynamic cohort of hospitals participating in hospital-wide and intensive care unit bloodstream infection surveillance for at least one full year over 2000 to 2014. Mixed-effects negative binomial regression analysis calculated the peak-to-low ratio between months as an adjusted CLABSI incidence rate ratio (IRR) with 95% confidence intervals (CI). Multivariate regression models examined the associations between CLABSI pathogens and ambient temperature and relative humidity. The study population included 104 hospital sites comprising 11,239 CLABSI. Regression analysis identified a hospital-wide increase in total CLABSI during July-August, with a higher gram-negative peak-to-low incidence rate ratio (IRR 2.52 [95% CI 1.92-3.30], p < 0.001) compared to gram-positive bacteria (IRR 1.29 [95% CI 1.11-1.48], p < 0.001). Subgroup analysis replicated this trend for CLABSI diagnosed in the intensive care unit. Only gram-negative CLABSI rates were associated with increased temperature (IRR + 30.3% per 5 °C increase [95% CI 17.3-43.6], p < 0.001) and humidity (IRR + 22.9% per 10% increase [95% CI 7.7-38.3), p < 0.001). The incidence and proportion of gram-negative CLABSI approximately doubled during the summer periods. Ambient temperature and humidity were associated with increases of hospital-acquired gram-negative infections. CLABSI surveillance, preventive intervention trials and epidemiological studies should consider seasonal variation and climatological factors when preparing study designs or interpreting their results. Central venous catheters (CVC) are necessary for medication, fluid, and blood product infusion, and hemodialysis. Unfortunately, these invasive devices can lead to preventable central line-associated bloodstream infections (CLABSI) 1. CLABSIs can lead to septic shock, hematogenous bacterial seeding with organ infection, increased length of hospitalization and costs, which impact morbidity and prognosis 2. CLABSI rates are primarily dependent on exposure risk: central line catheterization and duration. Considering this exposure, other risk factors include catheter type, insertion site and infection prevention practices. Reported infection rates for non-tunneled short-term CVCs range around 4.4 per 100 catheters, 2.7 per 1000 catheter-days and 1.6 per 10,000 patient-days, but depends on quality of care with adherence to preventive hygienic measures 3,4. Infection seasonality has been well documented for influenza and more recently among bacterial infections. Increased summer incidence has been documented for gram-negative infections 5,6 , BSI 7-15 , hospital-acquired

Lancet Infectious Diseases, Apr 1, 2021

Elsevier has created a COVID-19 resource centre with free information in English and Mandarin on ... more Elsevier has created a COVID-19 resource centre with free information in English and Mandarin on the novel coronavirus COVID-19. The COVID-19 resource centre is hosted on Elsevier Connect, the company's public news and information website. Elsevier hereby grants permission to make all its COVID-19-related research that is available on the COVID-19 resource centre-including this research content-immediately available in PubMed Central and other publicly funded repositories, such as the WHO COVID database with rights for unrestricted research re-use and analyses in any form or by any means with acknowledgement of the original source. These permissions are granted for free by Elsevier for as long as the COVID-19 resource centre remains active.

Archives of public health, Sep 17, 2015

Eurosurveillance, Dec 2, 2021

Background: COVID-19-related mortality in Belgium has drawn attention for two reasons: its high l... more Background: COVID-19-related mortality in Belgium has drawn attention for two reasons: its high level, and a good completeness in reporting of deaths. An ad hoc surveillance was established to register COVID-19 death numbers in hospitals, long-term care facilities (LTCF) and the community. Belgium adopted broad inclusion criteria for the COVID-19 death notifications, also including possible cases, resulting in a robust correlation between COVID-19 and all-cause mortality. Aim: To document and assess the COVID-19 mortality surveillance in Belgium. Methods: We described the content and data flows of the registration and we assessed the situation as of 21 June 2020, 103 days after the first death attributable to COVID-19 in Belgium. We calculated the participation rate, the notification delay, the percentage of error detected, and the results of additional investigations. Results: The participation rate was 100% for hospitals and 83% for nursing homes. Of all deaths, 85% were recorded within 2 calendar days: 11% within the same day, 41% after 1 day and 33% after 2 days, with a quicker notification in hospitals than in LTCF. Corrections of detected errors reduced the death toll by 5%. Conclusion: Belgium implemented a rather complete surveillance of COVID-19 mortality, on account of a rapid investment of the hospitals and LTCF. LTCF could build on past experience of previous surveys and surveillance activities. The adoption of an extended definition of 'COVID-19-related deaths' in a context of limited testing capacity has provided timely information about the severity of the epidemic.

European Journal of Clinical Microbiology & Infectious Diseases, Feb 11, 2021

In 2019, an outbreak of Shigella sonnei occurred during two youth camps in Belgium. The clusterin... more In 2019, an outbreak of Shigella sonnei occurred during two youth camps in Belgium. The clustering of isolates from both camps was confirmed by next-generation sequencing, as well as a secondary infection of a technician. The outbreak strain clustered with internationally isolated strains from patients with recent travel history to Central America. This report exemplifies enhanced surveillance and international collaboration between public health institutes by enabling to link local outbreaks to region-specific sublineages circulating abroad.

Epidemiology and Infection, 2019

A cluster of Legionnaires' disease (LD) with 10 confirmed, three probable and four possible c... more A cluster of Legionnaires' disease (LD) with 10 confirmed, three probable and four possible cases occurred in August and September 2016 in Dendermonde, Belgium. The incidence in the district was 7 cases/100 000 population, exceeding the maximum annual incidence in the previous 5 years of 1.5/100 000. Epidemiological, environmental and geographical investigations identified a cooling tower (CT) as the most likely source. The case risk around the tower decreased with increasing distance and was highest within 5 km.Legionella pneumophilaserogroup 1, ST48, was identified in a human respiratory sample but could not be matched with the environmental results. Public health authorities imposed measures to control the contamination of the CT and organised follow-up sampling. We identified obstacles encountered during the cluster investigation and formulated recommendations for improved LD cluster management, including faster coordination of teams through the outbreak control team, improv...

Antimicrobial Resistance and Infection Control, 2015

PLOS ONE

The goal of tracing, testing, and quarantining contacts of infected individuals is to contain the... more The goal of tracing, testing, and quarantining contacts of infected individuals is to contain the spread of infectious diseases, a strategy widely used during the COVID-19 pandemic. However, limited research exists on the effectiveness of contact tracing, especially with regard to key performance indicators (KPIs), such as the proportion of cases arising from previously identified contacts. In our study, we analyzed contact tracing data from Belgium collected between September 2020 and December 2021 to assess the impact of contact tracing on SARS-CoV-2 transmission and understand its characteristics. Among confirmed cases involved in contact tracing in the Flemish and Brussels-Capital regions, 19.1% were previously identified as close contacts and were aware of prior exposure. These cases, referred to as ‘known’ to contact tracing operators, reported on average fewer close contacts compared to newly identified individuals (0.80 versus 1.05), resulting in fewer secondary cases (0.23 ...

Scientific Reports, Mar 15, 2023

Understanding the local dynamics of COVID-19 transmission calls for an approach that characterize... more Understanding the local dynamics of COVID-19 transmission calls for an approach that characterizes the incidence curve in a small geographical unit. Given that incidence curves exhibit considerable day-today variation, the fractal structure of the time series dynamics is investigated for the Flanders and Brussels Regions of Belgium. For each statistical sector, the smallest administrative geographical entity in Belgium, fractal dimensions of COVID-19 incidence rates, based on rolling time spans of 7, 14, and 21 days were estimated using four different estimators: box-count, Hall-Wood, variogram, and madogram. We found varying patterns of fractal dimensions across time and location. The fractal dimension is further summarized by its mean, variance, and autocorrelation over time. These summary statistics are then used to cluster regions with different incidence rate patterns using k-means clustering. Fractal dimension analysis of COVID-19 incidence thus offers important insight into the past, current, and arguably future evolution of an infectious disease outbreak.

SSRN Electronic Journal, 2022

Background A low mid-upper arm circumference (MUAC) <115 mm is increasingly used as a stand-alone... more Background A low mid-upper arm circumference (MUAC) <115 mm is increasingly used as a stand-alone anthropometric admission criterion for nutritional rehabilitation of severely acute malnourished children, alongside a low weight-for-height z-score (WHZ) <-3. As these two indicators correlate poorly, we reviewed the evidence on the comparative outcomes of children with severe acute malnutrition (SAM) admitted to and discharged from nutritional rehabilitation programmes on the basis of either MUAC or WHZ. The utilization of bilateral pitting oedema as an independent indicator of SAM was out of the scope of our review. Methods We searched Medline, Embase, the CRD databases, the Cochrane Library and grey literature for evidence on mortality, recovery, treatment duration, costs, adverse events and population coverage when admission of SAM children was based on MUAC vs WHZ. Findings Eleven studies were included. Only one cohort study directly compared children with a MUAC <115 mm and those with WHZ <-3 at the start of the nutritional rehabilitation. It reported similar mortality rates in both groups, although different causalities might have been involved as a low MUAC was more associated with stunting, younger age, being a female and nutritional oedema than a low WHZ. Four studies admitted SAM children on the basis of MUAC only. The mortality risk was relatively low in three studies (2.1%). The mean standard deviation (±SD) recovery time ranged from 44±30 days to 50±26 days, and the daily MUAC gain from 0.17±0.16 mm to 0.51±0.3 mm. These findings were consistent with six additional studies where WHZ but not MUAC was the admission criterion. Overall, the increase in MUAC paralleled the daily weight gain, which ranged between 2.0 and 6.5 g/kg/day. One study reported a lower daily MUAC gain when children were younger and smaller, and in females. Two studies discharged children on the basis of MUAC (MUAC ≥124 mm only or MUAC ≥130 mm), but did not report on outcomes after discharge. The most appropriate MUAC cutoff for discharge is thus unknown. No study reported on costs, adverse effects or population coverage. No study assessed the outcomes of children with a low WHZ excluded from treatment because they did not fulfil the MUAC stand-alone admission criterion. Conclusion There are indications that MUAC could be used adequately as a stand-alone criterion for SAM children to be admitted to and discharged from nutritional rehabilitation programmes. However, the evidence base is currently insufficient. More data are particularly needed on the risks of children with a low WHZ not treated for SAM where MUAC is used as a stand-alone criterion. The extent to which factors such as age, sex and stunting affect the rehabilitation outcomes in children admitted with MUAC <115 mm must also be clarified. There are numerous nutritional programmes currently active worldwide and their thorough evaluation could generate such data in the short term.

Pediatrics, Nov 1, 2004

Objective. To acquire a deeper understanding of factors that influence adherence to highly active... more Objective. To acquire a deeper understanding of factors that influence adherence to highly active antiretroviral therapy (HAART) in a pediatric population. Methods. We performed a qualitative study of adherence in children who receive HAART in a Belgian pediatric acquired immune deficiency syndrome referral center. Eleven primary caregivers were interviewed to assess their child's adherence and influencing factors. The interview guidelines were developed on the basis of an extensive literature review. Adherence to treatment was assessed using caregivers' self-report and laboratory results. Content analysis for common items was performed, and statements of adherent and less-adherent patients were compared. Results. Three main factors influenced adherence. Adherent patients were found to internalize the medical information to a stronger extent than less-adherent patients. Adherent patients showed stronger motivation to stick to the medical regimen on the basis of personal cost-benefit analyses, ie, perceived benefits outweighed the costs or difficulties experienced. Adherent patients developed greater problem-solving capacities, ie, ways to deal with practical complications of medication intake. The interviews revealed a fourth, more dynamic component: knowledge, motivation, and capacities evolved in a progressive way, related to individual stages of coping with human immunodeficiency virus (HIV). Conclusions. The data suggest that coping with HIV and the process of establishing good adherence may be interrelated. Caregivers who accept the disease may be more likely to internalize the received information and thus develop a stronger motivation to fight for the child's life. Problem-solving skills sustain this adherence, and medication becomes a priority in the adherent caregivers' daily lives. On the contrary, less-adherent caregivers may be situated at less advanced stages of the coping process. Thus, tailor-made approaches adapted to the individual HIV-related coping strategies need to be developed to improve adherence in children and caregivers. Pediatrics 2004;114:e591-e597.