Suchergebnisse

BACKGROUND: Incomplete immunisation coverage causes preventable illness and death in both developing and developed countries. Identification of factors that might modulate coverage could inform effective immunisation programmes and policies. We constructed a performance indicator that could quantitatively approximate measures of the susceptibility of immunisation programmes to coverage losses, with an aim to identify correlations between trends in vaccine coverage and socioeconomic factors. METHODS: We undertook a data-driven time-series analysis to examine trends in coverage of diphtheria, tetanus, and pertussis (DTP) vaccination across 190 countries over the past 30 years. We grouped countries into six world regions according to WHO classifications. We used Gaussian process regression to forecast future coverage rates and provide a vaccine performance index: a summary measure of the strength of immunisation coverage in a country. FINDINGS: Overall vaccine coverage increased in all six world regions between 1980 and 2010, with variation in volatility and trends. Our vaccine performance index identified that 53 countries had more than a 50% chance of missing the Global Vaccine Action Plan (GVAP) target of 90% worldwide coverage with three doses of DTP (DTP3) by 2015. These countries were mostly in sub-Saharan Africa and south Asia, but Austria and Ukraine also featured. Factors associated with DTP3 immunisation coverage varied by world region: personal income (Spearman's ρ=0·66, p=0·0011) and government health spending (0·66, p<0·0001) were informative of immunisation coverage in the Eastern Mediterranean between 1980 and 2010, whereas primary school completion was informative of coverage in Africa (0·56, p<0·0001) over the same period. The proportion of births attended by skilled health staff correlated significantly with immunisation coverage across many world regions. INTERPRETATION: Our vaccine performance index highlighted countries at risk of failing to achieve the GVAP target of 90% coverage by 2015, and could aid policy makers' assessments of the strength and resilience of immunisation programmes. Weakening correlations with socioeconomic factors show a need to tackle vaccine confidence, whereas strengthening correlations point to clear factors to address. FUNDING: UK Engineering and Physical Sciences Research Council.

Background Incomplete immunisation coverage causes preventable illness and death in both the developing and developed world. Identifying factors that may modulate coverage can inform effective immunisation programmes and policies. Methods We perform a data-driven analysis of unprecedented scale, examining time-varying trends in Diphtheriatetanus-pertussis coverage across 190 countries over the past three decades. Gaussian process regression is employed to forecast future coverage rates and provide a Vaccine Performance Index: a summary measure of the strength of immunisation coverage in a country. Findings Overall vaccine coverage has increased in all five world regions between 1980 and 2010, with marked variation in volatility and trends. Our Vaccine Performance Index identifies 53 countries with a less than 50% chance of missing the Global Vaccine Action Plan (GVAP) target of 90% worldwide DTP3 coverage by 2015, in agreement with recent immunisation data. These countries are mostly sub-Saharan and South Asian, but Austria and Ukraine in Europe also feature. Factors associated with DTP3 immunisation coverage vary by world-region: personal income (! = 0.66, ' < 0.001) and government health spending (! = 0.66, ' < 0.01) are particularly informative in the Eastern Mediterranean between 1980 and 2010, whilst primary school completion is informative in Africa (! = 0.56, ' < 0.001) over the same time. The fraction of births attended by skilled health staff is significantly informative across many world regions Interpretation A Vaccine Performance Index can highlight countries at risk identifying the strength and resilience of immunisation programmes. Weakening correlations with socio-economic factors indicate a need to tackle vaccine confidence whereas strengthening correlations points to clear factors to address.