May Sherif ElSherif

May Sherif ElSherif
Dalhousie University | Dal

MD, MPH

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50
Publications
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Publications

Publications (50)
Article
BACKGROUND: Serological assays designed to detect SARS-CoV-2 antibodies are being used in serological surveys and other specialized applications. As a result, and to ensure that the outcomes of serological testing meet high quality standards, evaluations are required to assess the performance of these assays and the proficiency of laboratories perf...
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Background We report characteristics and outcomes of adults admitted to Canadian Immunization Research Network (CIRN) Ser-ious Outcomes Surveillance (SOS) Network hospitals with COVID-19 in 2020. Methods Patients with laboratory-confirmed COVID-19 admitted to 11 sites in Ontario, Quebec, Alberta, and Nova Scotia up to December 31, 2020 were enrolle...
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Objective(s) In the context of age- and risk-based pneumococcal vaccine recommendations in Canada, this study presents updated data from active surveillance of pneumococcal community acquired pneumonia (pCAP) and invasive pneumococcal disease (IPD) in hospitalized adults from 2010 to 2017. Methods S. pneumoniae was detected using culture (blood an...
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Background Pneumococcal vaccine recommendations in Canada include both age- and risk-based guidance. This study aimed to describe the burden of vaccine-preventable pneumococcal community acquired pneumonia (pCAP) and invasive pneumococcal disease (IPD) by age in hospitalized adults. Methods Active surveillance for all-cause CAP and IPD in hospital...
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Inactivated influenza vaccines efficacy is variable and often poor. We conducted a phase 1 trial (NCT02188810), to assess the safety and immunogenicity of a novel nanoparticle Toll-like receptor 7/8 agonist adjuvant (Papaya Mosaic Virus) at different dose levels combined with trivalent influenza vaccine in healthy persons 18–50 years of age. Hemagg...
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Background In Canada, 13-valent pneumococcal conjugate vaccine (PCV13) is recommended in childhood, in individuals at high risk of invasive pneumococcal disease (IPD) and in healthy adults aged ≥65 years for protection against vaccine-type IPD and pneumococcal community-acquired pneumonia (pCAP). Since vaccine recommendations in Canada include both...
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Background In healthy adults aged ≥65 years, direct immunization with the 13-valent pneumococcal conjugate vaccine (PCV13) was shown effective at preventing vaccine-type pneumococcal community-acquired pneumonia (pCAP) and invasive pneumococcal disease (IPD). Although PCV13 was licensed for use in Canadian adults aged >50 years, it was recommended...
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Background Streptococcus pneumoniae can colonizes the human nasopharynx, and can cause life-threatening infections like community-acquired pneumonia (CAP) and invasive pneumococcal diseases (IPD). In Canada, the 13-valent conjugate vaccine (PCV13) was introduced in childhood immunization since 2010, with hopes that it would not only protect the vac...
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Background Inactivated influenza vaccines (IV) efficacy is variable and sometimes poor. In this phase 1 trial the safety and immunogenicity of a novel nanoparticle adjuvant (Papaya Mosaic Virus (PapMV or PAL) at different dose levels combined with inactivated trivalent IV (TIV; FLUVIRAL® 2013–2014, GSK, Kirkland PQ) was assessed. Nonpathogenic in m...
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Background: Recent studies have demonstrated the possibility of negative associations between prior influenza vaccines and subsequent influenza vaccine effectiveness (VE), depending on season and strain. We investigated this association over 4 consecutive influenza seasons (2011-2012 through 2014-2015) in Canada. Methods: Using a matched test-ne...
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Background: The Serious Outcomes Surveillance Network of the Canadian Immunization Research Network (CIRN SOS) has been performing active influenza surveillance since 2009 (ClinicalTrials.gov identifier: NCT01517191). Influenza A and B viruses are identified and characterized using real-time reverse-transcriptase polymerase chain reaction (RT-PCR)...
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Background: The 13-valent pneumococcal conjugate vaccine (PCV13) was recently shown to be effective against PCV13-type invasive pneumococcal disease (IPD) and pneumococcal community acquired pneumonia (CAPSpn) in healthy adults aged ≥65 years, prompting many countries to re-assess adult immunization. In Canada, the potential benefits of adult PCV1...
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Background: The effectiveness of influenza vaccination in reducing influenza-related hospitalizations among patients with COPD is not well described, and influenza vaccination uptake remains suboptimal. Methods: Data were analyzed from a national, prospective, multicenter cohort study including patients with COPD, hospitalized with any acute res...
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Background Streptococcus pneumoniae is a bacterium that causes significant morbidity and mortality worldwide. Its capsular polysaccharides have been used successfully as vaccine antigens, and to characterize S. pneumoniae into 92 different serotypes. Phenotypic (Quellung reaction) or genotopic (PCR or sequencing) methods can be used for serotype as...
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Background To inform public health decision making around influenza prevention and treatment, ongoing surveillance of the influenza burden of disease and assessment of influenza vaccine effectiveness (VE) is critical. The Canadian Immunization Research Network (CIRN) Serious Outcomes Surveillance (SOS) Network conducts active surveillance each infl...
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Background Recent studies have shown that a 13-valent pneumococcal conjugate vaccine (PCV13) was effective at preventing vaccine-type pneumococcal community acquired pneumonia (CAPSpn) in healthy adults. With the anticipated herd immunity from routine infant immunization with PCV13 used since 2010, the benefits of adult immunization in Canada were...
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Background When assessing burden of influenza disease, influenza B has typically been associated with infection in children and young adults, and is considered less prevalent and/or severe in older adults. We sought to assess the burden of influenza type A disease compared with influenza type B disease in Canadian adults admitted to hospital with l...
Article
Background: Serotyping of Streptococcus pneumoniae is an integral part of disease surveillance, with over 92 serotypes characterized to date using traditional serotyping. To identify the most predominant disease causing serotypes, molecular serotyping methods are now increasingly being used, like conventional and real-time multiplex PCR (cmPCR and...
Article
Background: Immunization of pregnant women with tetanus-diphtheria-acellular pertussis vaccine (Tdap) provides protection against pertussis to the newborn infant. Methods: In a randomized, controlled, observer-blind, multicenter clinical trial, we measured the safety and immunogenicity of Tdap during pregnancy and the effect on the infant's immu...
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Background: Ongoing assessment of influenza vaccine effectiveness (VE) is critical to inform public health policy. This study aimed to determine the VE of trivalent influenza vaccine (TIV) for preventing influenza-related hospitalizations and other serious outcomes over three consecutive influenza seasons. Methods: The Serious Outcomes Surveilla...
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Background: The Serious Outcomes Surveillance (SOS) Network was established to monitor seasonal influenza complications among hospitalized Canadian adults and to assess the effectiveness of influenza vaccination against severe outcomes. Here we report age- and strain-specific vaccine effectiveness (VE) in preventing severe outcomes during a season...
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Background: Consideration of cost determinants is crucial to inform delivery of public vaccination programs. Objectives: To estimate the average total cost of laboratory-confirmed influenza requiring hospitalization in Canadians prior to, during, and 30 days following discharge. To analyze effects of patient/disease characteristics, treatment, a...
Article
Serotyping of Streptococcus pneumoniae is important to monitor disease epidemiology and assess the impact of pneumococcal vaccines. Traditionally, the Quellung reaction used serotype-specific antibodies to classify S. pneumoniae based on differences in capsular antigens. More recently, PCR-based serotype deduction relying on serotype-specific capsu...
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Background Recent controversy has arisen from observational studies suggesting a potential negative association between prior influenza vaccination and subsequent influenza vaccine effectiveness (VE). As immunologic theories suggest this impact could vary by season/strain, we investigated this association over 4 influenza seasons in Canada. Method...
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Background Antiviral treatment of influenza in outpatient settings is associated with modest improvement in outcomes but benefit in inpatient settings remains unclear. We assessed the impact of antiviral treatment on the severe outcomes death and intensive care unit (ICU) admission and/or need for mechanical ventilation (MV) in hospitalized influen...
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Background Influenza virus activity varies seasonally and within season. Epidemiology of serious influenza outcomes is contingent on the prevalent circulating strain/s and susceptible age group/s. Given the strain variability over the 2011–2012 through 2013–2014 seasons in Canada, this study examined the clinical and epidemiological profiles of dif...
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Background Influenza vaccination programs aim to prevent serious outcomes. Given that frailty may impact recovery from influenza, we examined frailty as a predictor of recovery in older adults hospitalized with acute respiratory illness. Methods Data came from the Canadian Immunization Research Network (CIRN) Serious Outcomes Surveillance (SOS) Ne...
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Background Pneumococcal community acquired pneumonia (CAP-Spn) and invasive pneumococcal disease (IPD) cause significant morbidity and mortality worldwide. Although childhood immunization programs have reduced the overall burden of pneumococcal disease in both children and adults (through herd immunity), there is insufficient data in Canada to info...
Article
Background: Influenza is an important cause of morbidity and mortality among older adults. Even so, effectiveness of influenza vaccine for older adults has been reported to be lower than for younger adults, and the impact of frailty on vaccine effectiveness (VE) and outcomes is uncertain. We aimed to study VE against influenza hospitalization in o...
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Background: The 2013-2016 Ebola virus outbreak in West Africa was the most widespread in history. In response, alive attenuated recombinant vesicular stomatitis virus (rVSV) vaccine expressing Zaire Ebolavirus glycoprotein (rVSVΔG-ZEBOV-GP) was evaluated in humans. Methods: In a phase 1, randomized, dose-ranging, observer-blind, placebo-controll...
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Study design Detection and serotyping of Streptococcus pneumoniae are important to assess the impact of pneumococcal vaccines. This study describes the diagnostic accuracy of PCR-based detection of S. pneumoniae directly from nasopharyngeal (NP) swabs collected for respiratory virus studies. Methods Active surveillance for community-acquired pneum...
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Full-text available
Background: Pneumococcal community acquired pneumonia (CAPSpn) and invasive pneumococcal disease (IPD) cause significant morbidity and mortality worldwide. Although childhood immunization programs have reduced the overall burden of pneumococcal disease, there is insufficient data in Canada to inform immunization policy in immunocompetent adults. T...
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Full-text available
Conventional multiplex PCR (cmPCR) reactions have been developed to monitor the most predominant serotypes of Streptococcus pneumoniae causing invasive pneumococcal disease (IPD). Since cmPCR assigns serotypes based on differences in the capsule biosynthesis (cps) loci, DNA extracted from clinical specimens can be used directly to monitor changes i...
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Monitoring Streptococcus pneumoniae serotype distribution is important to assess the impact and effectiveness of pneumococcal vaccine programs. With the challenges of Quellung serotyping, PCR-based serotype prediction is increasingly being used for large-scale epidemiological studies. This study used real-time (RT)-PCR targeting the genes encoding...
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The 2014/15 influenza season in Canada has been characterised to date by early and intense activity dominated by influenza A(H3N2). A total of 99.0% (593/599) hospitalisations for laboratory-confirmed influenza with a known influenza virus type enrolled in sentinel hospitals of the Serious Outcomes Surveillance Network of the Canadian Immunization...
Article
Infants under 6 months of age are at greatest risk of mortality and severe morbidity from pertussis disease. Interventions that increase pertussis protection in newborns are therefore a clear public health imperative. The objective of this study was to assess maternal pertussis toxin antibody (anti-PT) level as a potential source of mother-to-child...
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During the 2013/14 influenza season in Canada, 631 of 654 hospitalisations for laboratory-confirmed influenza enrolled in sentinel hospitals were due to Influenza A. Of the 375 with known subtype, influenza A(H1N1) accounted for 357. Interim unmatched vaccine effectiveness adjusted for age and presence of one or more medical comorbidities was deter...
Conference Paper
Background: Community acquired pneumonia (CAP) and invasive pneumococcal disease (IPD) are important contributors to morbidity and mortality among Canadian adults. Adult immunization with polysaccharide pneumococcal vaccines results in suboptimal disease prevention. Establishing burden of disease and healthcare utilization associated with CAP and I...
Conference Paper
Background: Turnaround time and simplicity of real-time Reverse Transcriptase Polymerase Chain Reaction (rRT-PCR) assays make them essential tools for influenza vaccine effectiveness (VE) studies. Specimens tested for presence of Influenza A or B strains, and further characterization of subtype or lineage allows VE measurement against vaccine match...
Conference Paper
Background: Nasopharyngeal (NP) colonization with S. pneumoniae (Spn) is common in children; conjugate pneumococcal vaccines reduce rates of NP colonization resulting in direct and indirect disease prevention. Colonization rates and serotype distribution have not been well characterized in adults. This information is critical to predict and monitor...
Conference Paper
Background: Influenza-like-illness (ILI) can be caused by a variety of respiratory viral infections, including influenza. While many cases of ILI are not caused by influenza, ILI activity in the community is a useful surrogate for influenza activity. Several case definitions of ILI exist. We examine the performance characteristics of the Public Hea...

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