Last data update: Apr 28, 2025. (Total: 49156 publications since 2009)
Records 1-6 (of 6 Records) |
Query Trace: Hajjeh RA[original query] |
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MenAfriNet: A network supporting case-based meningitis surveillance and vaccine evaluation in the meningitis belt of Africa
Patel JC , Soeters HM , Diallo AO , Bicaba BW , Kadade G , Dembele AY , Acyl MA , Nikiema C , Lingani C , Hatcher C , Acosta AM , Thomas JD , Diomande F , Martin S , Clark TA , Mihigo R , Hajjeh RA , Zilber CH , Ake F , Mbaeyi SA , Wang X , Moisi JC , Ronveaux O , Mwenda JM , Novak RT . J Infect Dis 2019 220 S148-s154 Meningococcal meningitis remains a significant public health threat, especially in the African meningitis belt where Neisseria meningitidis serogroup A historically caused large-scale epidemics. With the rollout of a novel meningococcal serogroup A conjugate vaccine (MACV) in the belt, the World Health Organization recommended case-based meningitis surveillance to monitor MACV impact and meningitis epidemiology. In 2014, the MenAfriNet consortium was established to support strategic implementation of case-based meningitis surveillance in 5 key countries: Burkina Faso, Chad, Mali, Niger, and Togo. MenAfriNet aimed to develop a high-quality surveillance network using standardized laboratory and data collection protocols, develop sustainable systems for data management and analysis to monitor MACV impact, and leverage the surveillance platform to perform special studies. We describe the MenAfriNet consortium, its history, strategy, implementation, accomplishments, and challenges. |
Case-control vaccine effectiveness studies: Data collection, analysis and reporting results
Verani JR , Baqui AH , Broome CV , Cherian T , Cohen C , Farrar JL , Feikin DR , Groome MJ , Hajjeh RA , Johnson HL , Madhi SA , Mulholland K , O'Brien KL , Parashar UD , Patel MM , Rodrigues LC , Santosham M , Scott JA , Smith PG , Sommerfelt H , Tate JE , Victor JC , Whitney CG , Zaidi AK , Zell ER . Vaccine 2017 35 (25) 3303-3308 The case-control methodology is frequently used to evaluate vaccine effectiveness post-licensure. The results of such studies provide important insight into the level of protection afforded by vaccines in a 'real world' context, and are commonly used to guide vaccine policy decisions. However, the potential for bias and confounding are important limitations to this method, and the results of a poorly conducted or incorrectly interpreted case-control study can mislead policies. In 2012, a group of experts met to review recent experience with case-control studies evaluating vaccine effectiveness; we summarize the recommendations of that group regarding best practices for data collection, analysis, and presentation of the results of case-control vaccine effectiveness studies. Vaccination status is the primary exposure of interest, but can be challenging to assess accurately and with minimal bias. Investigators should understand factors associated with vaccination as well as the availability of documented vaccination status in the study context; case-control studies may not be a valid method for evaluating vaccine effectiveness in settings where many children lack a documented immunization history. To avoid bias, it is essential to use the same methods and effort gathering vaccination data from cases and controls. Variables that may confound the association between illness and vaccination are also important to capture as completely as possible, and where relevant, adjust for in the analysis according to the analytic plan. In presenting results from case-control vaccine effectiveness studies, investigators should describe enrollment among eligible cases and controls as well as the proportion with no documented vaccine history. Emphasis should be placed on confidence intervals, rather than point estimates, of vaccine effectiveness. Case-control studies are a useful approach for evaluating vaccine effectiveness; however careful attention must be paid to the collection, analysis and presentation of the data in order to best inform evidence-based vaccine policies. |
Case-control vaccine effectiveness studies: Preparation, design, and enrollment of cases and controls
Verani JR , Baqui AH , Broome CV , Cherian T , Cohen C , Farrar JL , Feikin DR , Groome MJ , Hajjeh RA , Johnson HL , Madhi SA , Mulholland K , O'Brien KL , Parashar UD , Patel MM , Rodrigues LC , Santosham M , Scott JA , Smith PG , Sommerfelt H , Tate JE , Victor JC , Whitney CG , Zaidi AK , Zell ER . Vaccine 2017 35 (25) 3295-3302 Case-control studies are commonly used to evaluate effectiveness of licensed vaccines after deployment in public health programs. Such studies can provide policy-relevant data on vaccine performance under 'real world' conditions, contributing to the evidence base to support and sustain introduction of new vaccines. However, case-control studies do not measure the impact of vaccine introduction on disease at a population level, and are subject to bias and confounding, which may lead to inaccurate results that can misinform policy decisions. In 2012, a group of experts met to review recent experience with case-control studies evaluating the effectiveness of several vaccines; here we summarize the recommendations of that group regarding best practices for planning, design and enrollment of cases and controls. Rigorous planning and preparation should focus on understanding the study context including healthcare-seeking and vaccination practices. Case-control vaccine effectiveness studies are best carried out soon after vaccine introduction because high coverage creates strong potential for confounding. Endpoints specific to the vaccine target are preferable to non-specific clinical syndromes since the proportion of non-specific outcomes preventable through vaccination may vary over time and place, leading to potentially confusing results. Controls should be representative of the source population from which cases arise, and are generally recruited from the community or health facilities where cases are enrolled. Matching of controls to cases for potential confounding factors is commonly used, although should be reserved for a limited number of key variables believed to be linked to both vaccination and disease. Case-control vaccine effectiveness studies can provide information useful to guide policy decisions and vaccine development, however rigorous preparation and design is essential. |
Bacterial meningitis surveillance in the Eastern Mediterranean Region, 2005-2010: successes and challenges of a regional network
Teleb N , Pilishvili T , Van Beneden C , Ghoneim A , Amjad K , Mostafa A , Estighamati AR , Smeo MN , Barkia A , Elkhatib M , Mujaly A , Ashmony H , Jassim KA , Hajjeh RA . J Pediatr 2013 163 S25-31 OBJECTIVE: To describe epidemiology of bacterial meningitis in the World Health Organization Eastern Mediterranean Region countries and assist in introduction of new bacterial vaccines. STUDY DESIGN: A laboratory-based sentinel surveillance was established in 2004, and up to 10 countries joined the network until 2010. Personnel at participating hospitals and national public health laboratories received training in surveillance and laboratory methods and used standard clinical and laboratory-confirmed case definitions. RESULTS: Over 22 000 suspected cases of meningitis were reported among children ≤5 years old and >6600 among children >5 years old. In children ≤5 years old, 921 of 13 125 probable cases (7.0%) were culture-confirmed. The most commonly isolated pathogens were S pneumoniae (27% of confirmed cases), N meningitidis (22%), and H influenzae (10%). Among culture-confirmed case-patients with known outcome, case-fatality rate was 7.0% and 12.2% among children ≤5 years old and those >5 years old, respectively. Declining numbers of Haemophilus influenzae type b meningitis cases within 2 years post-Haemophilus influenzae type b conjugate vaccine introduction were observed in Pakistan. CONCLUSIONS: Bacterial meningitis continues to cause significant morbidity and mortality in the Eastern Mediterranean Region. Surveillance networks for bacterial meningitis ensure that all sites are using standardized methodologies. Surveillance data are useful to monitor impact of various interventions including vaccines, but maintaining data quality requires consistent reporting and regular technical support. |
International Conference on Emerging Infectious Diseases, 2010
Marano N , Smith TL , Hajjeh RA , McDonald M , Bridges CB , Martin SA , Chorba T . Emerg Infect Dis 2010 16 (11) e1 The seventh International Conference on Emerging Infectious Diseases (ICEID) was held in Atlanta, Georgia, USA, July 11-14, 2010. The conference goal was to bring together public health professionals to encourage exchange of scientific and public health information on global emerging infectious disease issues. The conference was organized by the Centers for Disease Control and Prevention (CDC), American Society for Microbiology, the Council of State and Territorial Epidemiologists, the Association of Public Health Laboratories, and the World Health Organization; additional support was provided by 40 other multidisciplinary public health partners. |
Supporting new vaccine introduction decisions: Lessons learned from the Hib Initiative experience
Hajjeh RA , Privor-Dumm L , Edmond K , O'Loughlin R , Shetty S , Griffiths UK , Bear AP , Cohen AL , Chandran A , Schuchat A , Mulholland EK , Santosham M . Vaccine 2010 28 (43) 7123-9 The introduction of Haemophilus influenzae type b (Hib) vaccine in developing countries has suffered from a long delay. Between 2005 and 2009, a surge in Hib vaccine adoption took place, particularly among GAVI-eligible countries. Several factors contributed to the increase in Hib vaccine adoption, including support provided by the Hib Initiative, a project funded by the GAVI Alliance in 2005 to accelerate evidence-informed decisions for use of Hib vaccine. This paper reviews the strategy adopted by the Hib Initiative and the lessons learned in the process, which provide a useful model to accelerate uptake of other new vaccines. |
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