The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Philippe De Wals - One of the best experts on this subject based on the ideXlab platform.
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Effectiveness of serogroup C meningococcal conjugate vaccine: a 7-year follow-up in Quebec, Canada.
The Pediatric infectious disease journal, 2011Co-Authors: Philippe De Wals, Geneviève Deceuninck, Nicole Boulianne, Brigitte Lefebvre, Gaston De SerresAbstract:Background:A Mass Immunization campaign was implemented in 2001 to control a serogroup C meningococcal disease outbreak, and a newly licensed serogroup C meningococcal conjugate vaccine (C-MCV) was used. In 2002, 1 C-MCV dose was routinely offered to children 12 months of age.Objective:To assess the
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Analysis of mortality following a Mass Immunization campaign with serogroup C meningococcal conjugate vaccine: methodological difficulties and imperfect solutions.
Vaccine, 2009Co-Authors: Philippe De Wals, Manale Ouakki, Gaston De Serres, Geneviève Deceuninck, Nicole Boulianne, Lisa DanzigAbstract:Abstract Background In 2001, a Mass Immunization campaign was implemented in the province of Quebec, Canada, using a new serogroup C meningococcal conjugate vaccine (C-MCV). Objective To describe methodological difficulties in the investigation of the mortality risk associated with administration of C-MCV using large administrative databases, and to present possible solutions. Materials and methods The study population included approximately 1.9 million residents in Quebec aged 2 months to 20 years. Death certificates in 2001 and 2002 were linked with vaccination registry data. Age-specific and age-adjusted mortality rates were compared between 1.4 million persons who had been vaccinated with C-MCV, and a mixed control group including 0.5 million individuals. In the C-MCV group, deaths within the 6-month period after vaccination were analyzed to identify any clustering, using the exponentially weighted moving average technique. Results All cause mortality was more than three times higher in the control group than in the C-MCV group, and the excess was seen for all major categories of causes. Two time-clusters were detected in the C-MCV group, but none of them appeared to be plausibly related to the administration of C-MCV. In the C-MCV group, there was no death caused by meningococcal disease, Guillain–Barre syndrome, anaphylactic shock, or a complication of vaccination. Conclusion Data concerning the safety of C-MCV are reassuring. However, the very strong “healthy vaccinee” effect limits our ability to detect any excess mortality risk in the vaccinated cohort and there is no perfect method to overcome this problem.
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Impact of a Mass Immunization campaign to cotrol an outbreak of severe respiratory infections in Nunavik, northern Canada
International journal of circumpolar health, 2006Co-Authors: Abdoul Aziz Ndiaye, Philippe De Wals, Jean-françois Proulx, Manale Ouakki, Louise Jetté, Serge DeryAbstract:Objectives. In spring 2002, a Mass Immunization campaign using a 23-valent pneumococcal polysaccharide vaccine (23-PPV) was launched in order to control an outbreak of severe pneumonia caused by a virulent clone of serotype 1 Streptococcus pneumoniae in Nunavik, Quebec, Canada. The objective of the study was to evaluate the impact of this campaign on the incidence of invasive pneumococcal disease (IPD) and hospitalizations possibly associated with pneumococcal infections (HPAPI) in the mostly Inuit population aged 10 to 64 years. Study design. Retrospective analysis of surveillance and administrative data. Methods. Multivariate Poisson model comparing the frequency rates of selected outcomes before the outbreak, during the outbreak, and after implementation of the Mass Immunization program. Results. The reported incidence of serotype 1 IPD decreased markedly after the implementation of the vaccination campaign (rate ratio = 0.16; p < 0.002). The frequency of HPAPI and the mean duration of hospital stay also decreased. However, vaccine failures were documented and the HPAPI rate remained higher than in the period prior to the outbreak. Conclusions. Although 23-PPV contributed to control the outbreak, better vaccines are needed for the prevention of infections caused by serotype 1 S. pneumoniae. (Int J Circumpolar Health 2006; 65(4): 297-304). Key words: pneumococcus, polysaccharide vaccine, Immunization, outbreak
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Effectiveness of a Mass Immunization Campaign Using Serogroup C Meningococcal Conjugate Vaccine
JAMA, 2004Co-Authors: Philippe De Wals, Geneviève Deceuninck, Nicole Boulianne, Gaston De SerresAbstract:ContextMeningococcal polysaccharide vaccines are of limited effectiveness. New protein-polysaccharide conjugate vaccines have yet to be evaluated in field conditions.ObjectiveTo assess the effectiveness of a serogroup C conjugate meningococcal vaccine in an outbreak setting.Design, Setting, and ParticipantsPopulation-based observational study of cases of invasive serogroup C meningococcal disease from 1996 through 2002 in Quebec identified from the provincial registry of notifiable diseases and from the provincial reference laboratory. In 2001, a Mass Immunization campaign with a conjugate vaccine was conducted to control an emerging epidemic. The number of vaccinated individuals was extracted from meningococcal Immunization registries.Main Outcome MeasuresIncidence of invasive meningococcal disease before and 1 year after the campaign in vaccinated and unvaccinated individuals.ResultsVaccination coverage of those 2 months to 20 years was 82.1%. After the campaign, the number of cases of serogroup C disease decreased from 58 in 2001 to 27 in 2002, and the incidence from 7.8 per million to 3.6 per million. Vaccine effectiveness was found to be 96.8% (95% confidence interval, 75.0%-99.9%). There was no observed increase in the incidence of the other serogroups.ConclusionThe new conjugate vaccine was effective in controlling an emerging epidemic of serogroup C meningococcal disease, as well as providing short-term protection across a wide age range.
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Cost-effectiveness of Immunization strategies for the control of serogroup C meningococcal disease
Vaccine, 2003Co-Authors: Philippe De Wals, Jean Drapeau, Van Hung Nguyen, Lonny J. Erickson, Maryse Guay, Jennifer St-laurentAbstract:This study compares the cost-effectiveness of a control strategy for serogroup C meningococcal disease (CMD) relying on surveillance and implementation of a Mass Immunization campaign effective 1 year after the beginning of an epidemic with strategies based on routine Immunization, using either three doses of serogroup C conjugate vaccine given in early infancy or one dose at 1 year of age. The simulation model is based on 25 birth cohorts followed up to age 24 years, and seven epidemiological scenarios including low and high level endemicity, and one to five epidemics over a 49-year period. Epidemiological and cost data were mainly collected in the province of Quebec, Canada. Results indicate that the most effective strategy is a three-dose routine program, with the least effective strategy being Mass Immunization. A one-dose routine program is the most cost-effective strategy in most likely scenarios. In a societal perspective with a vaccine purchase price of CDN$ 50 per dose, the average incremental cost of the one-dose strategy would be $ 190,000 per case averted, US$ 23,000 per life-year gained, and US$ 42,000 per QALY gained. If vaccine-induced immunity is waning rapidly, Mass Immunization or routine vaccination with booster dose(s) would be the best control options.
Nicole Boulianne - One of the best experts on this subject based on the ideXlab platform.
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Effectiveness of serogroup C meningococcal conjugate vaccine: a 7-year follow-up in Quebec, Canada.
The Pediatric infectious disease journal, 2011Co-Authors: Philippe De Wals, Geneviève Deceuninck, Nicole Boulianne, Brigitte Lefebvre, Gaston De SerresAbstract:Background:A Mass Immunization campaign was implemented in 2001 to control a serogroup C meningococcal disease outbreak, and a newly licensed serogroup C meningococcal conjugate vaccine (C-MCV) was used. In 2002, 1 C-MCV dose was routinely offered to children 12 months of age.Objective:To assess the
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Analysis of mortality following a Mass Immunization campaign with serogroup C meningococcal conjugate vaccine: methodological difficulties and imperfect solutions.
Vaccine, 2009Co-Authors: Philippe De Wals, Manale Ouakki, Gaston De Serres, Geneviève Deceuninck, Nicole Boulianne, Lisa DanzigAbstract:Abstract Background In 2001, a Mass Immunization campaign was implemented in the province of Quebec, Canada, using a new serogroup C meningococcal conjugate vaccine (C-MCV). Objective To describe methodological difficulties in the investigation of the mortality risk associated with administration of C-MCV using large administrative databases, and to present possible solutions. Materials and methods The study population included approximately 1.9 million residents in Quebec aged 2 months to 20 years. Death certificates in 2001 and 2002 were linked with vaccination registry data. Age-specific and age-adjusted mortality rates were compared between 1.4 million persons who had been vaccinated with C-MCV, and a mixed control group including 0.5 million individuals. In the C-MCV group, deaths within the 6-month period after vaccination were analyzed to identify any clustering, using the exponentially weighted moving average technique. Results All cause mortality was more than three times higher in the control group than in the C-MCV group, and the excess was seen for all major categories of causes. Two time-clusters were detected in the C-MCV group, but none of them appeared to be plausibly related to the administration of C-MCV. In the C-MCV group, there was no death caused by meningococcal disease, Guillain–Barre syndrome, anaphylactic shock, or a complication of vaccination. Conclusion Data concerning the safety of C-MCV are reassuring. However, the very strong “healthy vaccinee” effect limits our ability to detect any excess mortality risk in the vaccinated cohort and there is no perfect method to overcome this problem.
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Effectiveness of a Mass Immunization Campaign Using Serogroup C Meningococcal Conjugate Vaccine
JAMA, 2004Co-Authors: Philippe De Wals, Geneviève Deceuninck, Nicole Boulianne, Gaston De SerresAbstract:ContextMeningococcal polysaccharide vaccines are of limited effectiveness. New protein-polysaccharide conjugate vaccines have yet to be evaluated in field conditions.ObjectiveTo assess the effectiveness of a serogroup C conjugate meningococcal vaccine in an outbreak setting.Design, Setting, and ParticipantsPopulation-based observational study of cases of invasive serogroup C meningococcal disease from 1996 through 2002 in Quebec identified from the provincial registry of notifiable diseases and from the provincial reference laboratory. In 2001, a Mass Immunization campaign with a conjugate vaccine was conducted to control an emerging epidemic. The number of vaccinated individuals was extracted from meningococcal Immunization registries.Main Outcome MeasuresIncidence of invasive meningococcal disease before and 1 year after the campaign in vaccinated and unvaccinated individuals.ResultsVaccination coverage of those 2 months to 20 years was 82.1%. After the campaign, the number of cases of serogroup C disease decreased from 58 in 2001 to 27 in 2002, and the incidence from 7.8 per million to 3.6 per million. Vaccine effectiveness was found to be 96.8% (95% confidence interval, 75.0%-99.9%). There was no observed increase in the incidence of the other serogroups.ConclusionThe new conjugate vaccine was effective in controlling an emerging epidemic of serogroup C meningococcal disease, as well as providing short-term protection across a wide age range.
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Impact of a Mass Immunization campaign against serogroup C meningococcus in the Province of Quebec, Canada.
Bulletin of the World Health Organization, 1996Co-Authors: P. De Wals, Nicole Boulianne, Marc Dionne, Monique Douville-fradet, Jean Drapeau, G. De SerresAbstract:A Mass Immunization campaign was conducted in the Province of Quebec, Canada, during the winter of 1993, following an increase in the incidence of meningococcal disease, which was mainly caused by a virulent clone of Neisseria meningitidis, serogroup C, serotype 2a. About 1.6 million doses of the polysaccharide vaccine were administered, covering 84% of the target population aged between 6 months and 20 years; the overall cost was about 25.5 million Canadian dollars. Cases notified to the regional health authorities by clinicians, hospital laboratories, and the provincial reference laboratory from January 1990 up to March 1994 have been included in the analysis. In the first year following the campaign, the incidence of the disease dropped markedly among vaccinees as well as the unvaccinated fraction of the target population, while it remained unchanged among persons aged more than 20 years. This suggests the existence of herd immunity. The overall field efficacy of the vaccine was 79%, more in teenagers and less in under-5-year-olds. A minimum of 37 cases were prevented during the first year.
Gaston De Serres - One of the best experts on this subject based on the ideXlab platform.
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Effectiveness of serogroup C meningococcal conjugate vaccine: a 7-year follow-up in Quebec, Canada.
The Pediatric infectious disease journal, 2011Co-Authors: Philippe De Wals, Geneviève Deceuninck, Nicole Boulianne, Brigitte Lefebvre, Gaston De SerresAbstract:Background:A Mass Immunization campaign was implemented in 2001 to control a serogroup C meningococcal disease outbreak, and a newly licensed serogroup C meningococcal conjugate vaccine (C-MCV) was used. In 2002, 1 C-MCV dose was routinely offered to children 12 months of age.Objective:To assess the
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Analysis of mortality following a Mass Immunization campaign with serogroup C meningococcal conjugate vaccine: methodological difficulties and imperfect solutions.
Vaccine, 2009Co-Authors: Philippe De Wals, Manale Ouakki, Gaston De Serres, Geneviève Deceuninck, Nicole Boulianne, Lisa DanzigAbstract:Abstract Background In 2001, a Mass Immunization campaign was implemented in the province of Quebec, Canada, using a new serogroup C meningococcal conjugate vaccine (C-MCV). Objective To describe methodological difficulties in the investigation of the mortality risk associated with administration of C-MCV using large administrative databases, and to present possible solutions. Materials and methods The study population included approximately 1.9 million residents in Quebec aged 2 months to 20 years. Death certificates in 2001 and 2002 were linked with vaccination registry data. Age-specific and age-adjusted mortality rates were compared between 1.4 million persons who had been vaccinated with C-MCV, and a mixed control group including 0.5 million individuals. In the C-MCV group, deaths within the 6-month period after vaccination were analyzed to identify any clustering, using the exponentially weighted moving average technique. Results All cause mortality was more than three times higher in the control group than in the C-MCV group, and the excess was seen for all major categories of causes. Two time-clusters were detected in the C-MCV group, but none of them appeared to be plausibly related to the administration of C-MCV. In the C-MCV group, there was no death caused by meningococcal disease, Guillain–Barre syndrome, anaphylactic shock, or a complication of vaccination. Conclusion Data concerning the safety of C-MCV are reassuring. However, the very strong “healthy vaccinee” effect limits our ability to detect any excess mortality risk in the vaccinated cohort and there is no perfect method to overcome this problem.
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Effectiveness of a Mass Immunization Campaign Using Serogroup C Meningococcal Conjugate Vaccine
JAMA, 2004Co-Authors: Philippe De Wals, Geneviève Deceuninck, Nicole Boulianne, Gaston De SerresAbstract:ContextMeningococcal polysaccharide vaccines are of limited effectiveness. New protein-polysaccharide conjugate vaccines have yet to be evaluated in field conditions.ObjectiveTo assess the effectiveness of a serogroup C conjugate meningococcal vaccine in an outbreak setting.Design, Setting, and ParticipantsPopulation-based observational study of cases of invasive serogroup C meningococcal disease from 1996 through 2002 in Quebec identified from the provincial registry of notifiable diseases and from the provincial reference laboratory. In 2001, a Mass Immunization campaign with a conjugate vaccine was conducted to control an emerging epidemic. The number of vaccinated individuals was extracted from meningococcal Immunization registries.Main Outcome MeasuresIncidence of invasive meningococcal disease before and 1 year after the campaign in vaccinated and unvaccinated individuals.ResultsVaccination coverage of those 2 months to 20 years was 82.1%. After the campaign, the number of cases of serogroup C disease decreased from 58 in 2001 to 27 in 2002, and the incidence from 7.8 per million to 3.6 per million. Vaccine effectiveness was found to be 96.8% (95% confidence interval, 75.0%-99.9%). There was no observed increase in the incidence of the other serogroups.ConclusionThe new conjugate vaccine was effective in controlling an emerging epidemic of serogroup C meningococcal disease, as well as providing short-term protection across a wide age range.
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Effectiveness of a Mass Immunization Campaign Against Serogroup C Meningococcal Disease in Quebec
JAMA, 2001Co-Authors: Philippe De Wals, Gaston De Serres, Theophile NiyonsengaAbstract:ContextAn outbreak of meningococcal disease in Quebec province prompted a Mass Immunization program. The impact of this campaign on the epidemiology of meningococcal disease has not been studied.ObjectivesTo study the impact of a Mass Immunization campaign using polysaccharide vaccine on the epidemiology of meningococcal disease (MCD) and to assess serogroup C vaccine effectiveness (VE).Design, Setting, and SubjectsAnalysis of MCD cases reported in Quebec from 1990 to 1998, before and after the Mass Immunization campaign was conducted during the winter of 1992-1993, when 84% of residents aged 6 months to 20 years (the target population, approximately 1.9 million individuals) were vaccinated.Main Outcome MeasuresIncidence of MCD in 1990-1998; incidence of culture-proven serogroup C MCD between April 1, 1993, and March 31, 1998, compared among vaccinated and unvaccinated persons in the target population.ResultsThe incidence of serogroup C disease decreased after the Mass Immunization campaign, from 1.4 per 100 000 in 1990-1992 to 0.3 per 100 000 in 1993-1998, and the overall incidence of other serogroups remained stable at 0.7 per 100 000, with a small increase in the proportion of cases caused by serogroup Y (P = .009). Protection from serogroup C MCD was indicated in the first 2 years after vaccine administration (VE, 65%; 95% confidence interval [CI], 20%-84%), but not in the next 3 years (VE, 0%; 95% CI, −5% to 65%). Vaccine effectiveness was strongly related to age at vaccination: 83% (95% CI, 39%-96%) for ages 15 through 20 years, 75% (95% CI, − 17% to 93%) for ages 10 through 14 years, and 41% (95% CI, −106% to 79%) for ages 2 through 9 years. There was no evidence of protection in children younger than 2 years; all 8 MCD cases in this age group occurred in vaccinees.ConclusionsSerogroup C polysaccharide vaccine is effective for controlling outbreaks in teenaged individuals but should not be used in children younger than 2 years. The Mass campaign did not induce significant serogroup switching.
Amra Uzicanin - One of the best experts on this subject based on the ideXlab platform.
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Measles-rubella Mass Immunization campaign in Albania, November 2000.
The Journal of infectious diseases, 2003Co-Authors: Silvia Bino, Eduard Kakarriqi, Miriam Xibinaku, Nicolae Ion-nedelcu, Mariana Bukli, Nedret Emiroglu, Amra UzicaninAbstract:In 2000, Albania resolved to eliminate measles by 2007 by use of a four-step program: by conducting a "catch-up" vaccination campaign for all children aged 1-14 years, achieving and sustaining high coverage (>/=95%) among children aged 1 year with the first dose of a measles-containing vaccine, by introducing a routine second dose of measles-containing vaccine for children at age 5 years, and by improving measles surveillance. This catch-up campaign took place in November 2000: 867,000 doses of measles-rubella vaccine were administered for an estimated coverage of 99%. In all, 231 campaign-related adverse events were reported: syncope, 206; allergic reactions, 10; fever, 8; encephalitis/encephalopathy, 2; and aseptic meningitis, seizures, Guillain-Barré syndrome, anaphylaxis, and arthralgia, 1 each. All resolved without sequelae. This report describes the status of measles and rubella/congenital rubella syndrome control in Albania before 2000 and reports on implementation of the catch-up campaign.
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Measles-rubella Mass Immunization campaign in Albania, November 2000.
The Journal of Infectious Diseases, 2003Co-Authors: Silvia Bino, Eduard Kakarriqi, Miriam Xibinaku, Mariana Bukli, Nedret Emiroglu, Nicolae Ion‐nedelcu, Amra UzicaninAbstract:In 2000, Albania resolved to eliminate measles by 2007 by use of a four-step program: by conducting a "catch-up" vaccination campaign for all children aged 1-14 years, achieving and sustaining high coverage (>/=95%) among children aged 1 year with the first dose of a measles-containing vaccine, by introducing a routine second dose of measles-containing vaccine for children at age 5 years, and by improving measles surveillance. This catch-up campaign took place in November 2000: 867,000 doses of measles-rubella vaccine were administered for an estimated coverage of 99%. In all, 231 campaign-related adverse events were reported: syncope, 206; allergic reactions, 10; fever, 8; encephalitis/encephalopathy, 2; and aseptic meningitis, seizures, Guillain-Barre syndrome, anaphylaxis, and arthralgia, 1 each. All resolved without sequelae. This report describes the status of measles and rubella/congenital rubella syndrome control in Albania before 2000 and reports on implementation of the catch-up campaign.
Gilbert Burnham - One of the best experts on this subject based on the ideXlab platform.
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Evaluating the Experience of GAPS—A Methodology for Improving Quality of Mass Immunization Campaigns in Developing Countries
Journal of health population and nutrition, 2009Co-Authors: William Weiss, Gilbert Burnham, Peter J. WinchAbstract:The existence of pockets of under-vaccinated persons has allowed outbreaks of disease in countries that have achieved high levels of vaccination coverage. A field-based methodology—GAPS (Geographic Assessment of Planning and Services)—was developed to predict, in advance of an Immunization campaign, the sites of which are most likely to have a pocket of unvaccinated persons and then use this information to improve planning, supervision, and evaluation of the campaign. At this time, there have been two applications of GAPS (Nepal and Ethiopia). The purpose of this paper was to evaluate these two applications of GAPS and make recommendations regarding its future use. Structured, expert interviews were conducted with at least three campaign organizers to evaluate each application of GAPS using purposive sampling. An evaluation of an individual campaign was considered positive when at least two of the three campaign organizers considered GAPS to be useful and worthwhile. The three campaign organizers interviewed following the GAPS application in Ethiopia responded that GAPS was useful and worth the effort. In Nepal, all four campaign organizers responded that GAPS was useful and worth the effort. Some suggestions for improvement were also identified. Although this evaluation was limited in the number of applications evaluated, GAPS appears to have promise as a practical method to help improve the quality of Mass Immunization campaigns. And even if no pockets of unvaccinated persons are found, the method may serve as a rapid quality-check of administrative estimates of coverage. Further applications in different settings are needed to confirm these findings or under what circumstances GAPS might best be used. GAPS may also be considered for improving other types of health campaigns, such as distribution of insecticide-treated bednets, vitamin A capsules, and deworming medications.
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evaluating the experience of gaps a methodology for improving quality of Mass Immunization campaigns in developing countries
Journal of Health Population and Nutrition, 2009Co-Authors: William Weiss, Gilbert Burnham, Peter J. WinchAbstract:The existence of pockets of under-vaccinated persons has allowed outbreaks of disease in countries that have achieved high levels of vaccination coverage. A field-based methodology—GAPS (Geographic Assessment of Planning and Services)—was developed to predict, in advance of an Immunization campaign, the sites of which are most likely to have a pocket of unvaccinated persons and then use this information to improve planning, supervision, and evaluation of the campaign. At this time, there have been two applications of GAPS (Nepal and Ethiopia). The purpose of this paper was to evaluate these two applications of GAPS and make recommendations regarding its future use. Structured, expert interviews were conducted with at least three campaign organizers to evaluate each application of GAPS using purposive sampling. An evaluation of an individual campaign was considered positive when at least two of the three campaign organizers considered GAPS to be useful and worthwhile. The three campaign organizers interviewed following the GAPS application in Ethiopia responded that GAPS was useful and worth the effort. In Nepal, all four campaign organizers responded that GAPS was useful and worth the effort. Some suggestions for improvement were also identified. Although this evaluation was limited in the number of applications evaluated, GAPS appears to have promise as a practical method to help improve the quality of Mass Immunization campaigns. And even if no pockets of unvaccinated persons are found, the method may serve as a rapid quality-check of administrative estimates of coverage. Further applications in different settings are needed to confirm these findings or under what circumstances GAPS might best be used. GAPS may also be considered for improving other types of health campaigns, such as distribution of insecticide-treated bednets, vitamin A capsules, and deworming medications.
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Factors Associated with Missed Vaccination during Mass Immunization Campaigns
Journal of health population and nutrition, 2009Co-Authors: William Weiss, Peter J. Winch, Gilbert BurnhamAbstract:Achieving a high percentage of vaccination coverage with polio vaccine, while necessary, is not sufficient to eliminate or eradicate polio. The existence of pockets of under-vaccinated children has allowed outbreaks of polio in countries that have achieved high levels of vaccination coverage and in countries with no cases for many years. In a literature review, 35 articles were identified that described factors associated with missed vaccination in Mass Immunization campaigns. An annotated bibliography was developed for each article; these were then coded using the AnSWR program, and codes were organized into three larger thematic categories. These thematic areas were: (a) organization and implementation of Mass campaigns; (b) population characteristics; and (c) knowledge and practices of caretakers. If these factors were geographically clustered, it was suspected that these clusters might have higher likelihood of becoming pockets of unvaccinated children. Immunization programme managers can target resources to identify if such clusters exist. If so, they can then ensure supervision of vaccination efforts in those sites and take further action, if indicated, to prevent or mitigate pockets of unvaccinated children.