ESCAIDE 2016 poster

1. ESCAIDE 2016, 28-30 November, Stockholm, Sweden
Joana Vaz1,2, Simon Cottrell2, Christopher Williams2, Meirion Evans2
Impact of the introduction of the rotavirus vaccine in
reducing health inequalities in GP gastrointestinal
consultation rates in children under 5 in Wales
Rotavirus is the most common cause of severe gastroenteritis in children
Objectives
To compare pre and post-vaccination GE consultation rates:
To calculate any change in rates in children <5 years of age
To quantify any change in inequalities in rates by socio-economic
(deprivation ) quintiles.
Ecological study with different health inequality indicators
Reduced inequality in gastrointestinal consultation rates in children <2
ConclusionsLimitations
Recommendations
1) Mean annual incidence of GE consultations (10,000 practice
pop) by age group, pre and post RV vaccine
Data sources:
Wales GP dataset –GP consultation counts for GE;
GP practices categorised into 5 deprivation quintiles according to
practice population based on the Welsh Index of Multiple Deprivation
Study periods: Pre-vaccination (2011-13) and Post- vaccination
(2014-15) during rotavirus (RV) season (week 3-29)
Case definition: any diagnostic for GE in children <5 in Wales.
Other causes for gradient found, eg differences in vaccine uptake?
Disease coding and varied data quality by practice
Ecological fallacy
Assess herd immunity when all <5 years birth cohorts are vaccinated
Method should be applied to other vaccine preventable diseases
All inequality indicators suggest a reduction in health inequalities regarding
GE consultation rates in vaccinated cohorts (<2)
Remaining inequalities due to GE consultations for norovirus?
Vaccine double effect supports its maintenance in vaccine schedule
For information contact: joana.vaz@wales.nhs.uk
2) Mean annual incidence of GE consultations (10,000 practice pop) by
quintile of deprivation, pre and post RV vaccine ,age <2
Affiliation: 1European Programme for Intervention Epidemiology
Training (EPIET), ECDC, Sweden; 2Communicable disease Surveillance
Centre (CDSC), Public Health Wales, Cardiff, Wales
0
500
1000
1500
2000
pre (2011-13) post (2014-15)
Q1
Q2
Q3
Q4
Q5 Least deprived
Most deprived
Consultationrate
3) Inequality indicators show a significant decrease in the post period:
a) Absolute rate difference decreased from 356 (95%CI 438-275) to 152 (95%CI 233-72) consultations per 10,000 practice population
b) IRR increased from 0.78 (95%CI: 0.74-0.83) to 0.88 (95%CI: 0.83-0.94)
c) Health Concentration index decreased from -0.042 to -0.039
Age (years)
0
500
1000
1500
2000
0 1 2 3 4
Consultationrate
pre (2011-13)
post (2014-15)
17%
28 %
Consultation rates for GE decreased by 22% in children <2y Positive gradient of consultation rates with deprivation, in both periods
25% of General Practitioner (GP) consultations for gastroenteritis (GE)
Direct costs (NHS, families) and Indirect costs (carers)
Rotarix vaccine introduced in July 2013 (2doses:8&12 weeks)
Socio-economic gradient described; association not studied in Wales
Analysis: Comparison of pre and post vaccination indicators
1) Incidence by age
2) By deprivation quintile -Incidence rate ratios (IRR) using
multivariable binomial regression analysis
3) Calculation of Health inequality indicators:
a)Absolute rate difference = most (Q1) - least deprived (Q5) quintiles;
b)Incidence rate ratio (IRR)= most (Q1) / least deprived quintiles (Q5);
c)Health Concentration index which includes all deprivation quintiles,
range -1 to +1 (0 means no inequality).