Dataset Information

National Immunization Campaigns with Oral Polio Vaccine Reduce All-Cause Mortality: A Natural Experiment within Seven Randomized Trials.

ABSTRACT: Background:A recent WHO review concluded that live BCG and measles vaccine (MV) may have beneficial non-specific effects (NSEs) reducing mortality from non-targeted diseases. NSEs of oral polio vaccine (OPV) were not examined. If OPV vaccination campaigns reduce the mortality rate, it would suggest beneficial NSEs. Setting:Between 2002 and 2014, Guinea-Bissau had 15 general OPV campaigns and other campaigns with OPV plus vitamin A supplementation (VAS), VAS-only, MV, and H1N1 vaccine. In this period, we conducted seven randomized controlled trials (RCTs) with mortality as main outcome. Methods:Within these RCTs, we assessed whether the mortality rate was lower after-campaign than before-campaign. We used Cox models with age as underlying time and further adjusted for low birth-weight, season and time trend in mortality. We calculated the adjusted mortality rate ratio (MRR) for after-campaign vs before-campaign. Results:The mortality rate was lower after OPV-only campaigns than before, the MRR being 0.81 (95% CI?=?0.68-0.95). With each additional dose of campaign-OPV the mortality rate declined further (MRR?=?0.87 (95% CI: 0.79-0.96) per dose) (test for trend, p?=?0.005). No other type of campaign had similar beneficial effects. Depending on initial age and with follow-up to 3?years of age, the number needed to treat with campaign-OPV-only to save one life was between 68 and 230 children. Conclusion:Bissau had no case of polio infection so the results suggest that campaign-OPV has beneficial NSEs. Discontinuation of OPV-campaigns in low-income countries may affect general child mortality levels negatively.

SUBMITTER: Andersen A

PROVIDER: S-EPMC5801299 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

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National Immunization Campaigns with Oral Polio Vaccine Reduce All-Cause Mortality: A Natural Experiment within Seven Randomized Trials.

Andersen Andreas A Fisker Ane Baerent AB Rodrigues Amabelia A Martins Cesario C Ravn Henrik H Lund Najaaraq N Biering-Sørensen Sofie S Benn Christine Stabell CS Aaby Peter P

Frontiers in public health 20180202

<h4>Background</h4>A recent WHO review concluded that live BCG and measles vaccine (MV) may have beneficial non-specific effects (NSEs) reducing mortality from non-targeted diseases. NSEs of oral polio vaccine (OPV) were not examined. If OPV vaccination campaigns reduce the mortality rate, it would suggest beneficial NSEs.<h4>Setting</h4>Between 2002 and 2014, Guinea-Bissau had 15 general OPV campaigns and other campaigns with OPV plus vitamin A supplementation (VAS), VAS-only, MV, and H1N1 vacc ...[more]

PMID: 29456992

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Project description:BACKGROUND:Global efforts to eradicate wild polioviruses (WPVs) continue to face challenges due to uninterrupted endemic WPV transmission in three countries and importation-related outbreaks into previously polio-free countries. We explore the potential role of including older children and adults in supplemental immunization activities (SIAs) to more rapidly increase population immunity and prevent or stop transmission. METHODS:We use a differential equation-based dynamic poliovirus transmission model to analyze the epidemiological impact and vaccine resource implications of expanding target age groups in SIAs. We explore the use of older age groups in SIAs for three situations: alternative responses to the 2010 outbreak in Tajikistan, retrospective examination of elimination in two high-risk states in northern India, and prospective and retrospective strategies to accelerate elimination in endemic northwestern Nigeria. Our model recognizes the ability of individuals with waned mucosal immunity (i.e., immunity from a historical live poliovirus infection) to become re-infected and contribute to transmission to a limited extent. RESULTS:SIAs involving expanded age groups reduce overall caseloads, decrease transmission, and generally lead to a small reduction in the time to achieve WPV elimination. Analysis of preventive expanded age group SIAs in Tajikistan or prior to type-specific surges in incidence in high-risk areas of India and Nigeria showed the greatest potential benefits of expanded age groups. Analysis of expanded age group SIAs in outbreak situations or to accelerate the interruption of endemic transmission showed relatively less benefit, largely due to the circulation of WPV reaching individuals sooner or more effectively than the SIAs. The India and Nigeria results depend strongly on how well SIAs involving expanded age groups reach relatively isolated subpopulations that sustain clusters of susceptible children, which we assume play a key role in persistent endemic WPV transmission in these areas. CONCLUSIONS:This study suggests the need to carefully consider the epidemiological situation in the context of decisions to use expanded age group SIAs. Subpopulations of susceptible individuals may independently sustain transmission, which will reduce the overall benefits associated with using expanded age group SIAs to increase population immunity to a sufficiently high level to stop transmission and reduce the incidence of paralytic cases.

Project description:BackgroundStudies from Guinea-Bissau and Bangladesh have shown that campaigns with oral polio vaccine (C-OPV) may be associated with 25-31% lower child mortality. Between 1996 and 2015, Ghana had 50 national C-OPVs and numerous campaigns with vitamin A supplementation (VAS), and measles vaccine (MV). We investigated whether C-OPVs had beneficial non-specific effects (NSEs) on child survival in northern Ghana.MethodsWe used data from a health and demographic surveillance system in the Navrongo Health Research Centre in rural northern Ghana to examine mortality from day 1-5 years of age. We used Cox models with age as underlying time scale to calculate hazard ratios (HR) for the time-varying covariate "after-campaign" mortality versus "before-campaign" mortality, adjusted for temporal change in mortality, other campaign interventions and stratified for season at risk.FindingsFrom 1996 to 2015, 75,610 children were followed for 280,156 person-years between day 1 and 5 years of age. In initial analysis, assuming a common effect across all ages, we did not find that OPV-only campaigns significantly reduced all-cause mortality, the HR being 0.96 (95% CI: 0.88-1.05). However, we subsequently found the HR differed strongly by age group, being 0.92 (0.75-1.13), 1.29 (1.10-1.51), 0.79 (0.66-0.94), 0.67 (0.53-0.86) and 1.03 (0.78-1.36) respectively for children aged 0-2, 3-5, 6-8, 9-11 and above 12 months of age (p < 0.001). Triangulation of the evidence from this and previous studies suggested that increased frequency of C-OPVs and a different historical period could explain these results.InterpretationIn Ghana, C-OPVs had limited effects on overall child survival. However, triangulating the evidence suggested that NSEs of C-OPVs depend on age of first exposure and routine vaccination programs. C-OPVs had beneficial effects for children that were not exposed before 6 months of age. These non-specific effects of OPV should be exploited to further reduce child mortality.FundingDANIDA; Else og Mogens Wedell Wedellsborgs Fond.

Project description:BackgroundGlobally, community engagement is an integral part of most public health programs and the social mobilization (SM) intervention of India's polio eradication program is one such example that contributed to eliminating polio from the country. CORE Group Polio Project (CGPP), a partner of Uttar Pradesh (U.P.) SM Network executed its activities through a network of social mobilizers called Community Mobilization Coordinators (CMCs). These were deployed in polio high risk areas to perform awareness generation and trust-building activities with communities and achieved high coverage of polio vaccination during Supplementary Immunization Activity campaigns (SIAs). This paper measures the extent and outcomes of CMC community engagement in SM interventions and polio SIAs.MethodsThis study used secondary, cluster-level data from Management Information System of CGPP India, including 52 SIAs held between January 2008 to September 2017 in 56 blocks/polio planning units, covering 12 districts of U.P. We used five indicators that reflected community engagement in polio SIAs and constructed a Community Engagement Index (CEI). Further, we estimated the difference in the CEI between CMC and non-CMC areas, using Generalized Estimating Equations (GEE) and also estimated treatment effects through Difference-in-Differences (DID) method using STATA.ResultsOverall, 78.6% (95% confidence interval (CI) = 78.3, 78.8) of families from the study area were engaged in the polio SIAs and the extent of community engagement increased over time. The mean CEI of entire study period in CMC areas (85.8%; 95% CI = 85.6, 86.0) was significantly higher (P < 0.001) than that of non-CMC areas (71.3%; 95% CI = 71.1, 71.5). Over time, the SM intervention led to at least 11 percentage points increase in the CEI of CMC areas with about 17% of this achievement attributable to CGPP India's SM efforts.ConclusionsThe study findings suggest that intensive social mobilization efforts can significantly increase the extent of community engagement. The community engagement learnings of polio SM Network may be useful to achieve the desired outcomes of public health programs such as the National Health Mission (NHM) of India, that serves communities for multiple health issues.

Dataset Information

National Immunization Campaigns with Oral Polio Vaccine Reduce All-Cause Mortality: A Natural Experiment within Seven Randomized Trials.

Publications

National Immunization Campaigns with Oral Polio Vaccine Reduce All-Cause Mortality: A Natural Experiment within Seven Randomized Trials.

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