Download No RV5

Rotavirus vaccine coverage among a 2010 birth cohort
and risk factors for partial or no coverage, Washington State 2010
K. Stigi, C. DeBolt, K. Lofy
Washington State Department of Health – Office of Communicable Disease Epidemiology
Background
Results
• National Immunization Survey (NIS) 2009 and 2010
estimates ranked WA State among lowest in nation for
rotavirus coverage (20.9% and 50.4%, respectively)
Rotavirus vaccine coverage estimates using IIS data
2 months
Max: 14 wks, 6 days
4 months
1 http://www.cdc.gov/vaccines/recs/schedules
Rotavirus Dose
n=70,350 (80.6)
N= 62,597 matched records from 2010 birth cohort
Dose 3
6 months
Max: 8 mo, 0 days
Full
Coverage
n=52,468 (60.1)
/
No Rotavirus Dose
n=16,951 (19.4)
Age
2 Boom,
et al. Effectiveness of Pentavalent Rotavirus Vaccine in a Large Urban Population in the
United States, Pediatrics 2010. 3 Staat, et al. Effectiveness of Pentavalent Rotavirus Vaccine Against
Severe Disease, Pediatrics 2011.
Objective
To estimate rotavirus vaccine coverage in WA State using IIS
data, and to explore maternal characteristics associated with
partial or no rotavirus coverage
Partial
Coverage
n=17,882 (20.5)
No RV5
n=6,678 (7.6)
20-29
1.5 (1.36 1.72)
1.0 (0.82, 1.12)
30-39
1.1 (0.96, 1.2)
0.9 (0.74, 0.99)
• Rotavirus unique vaccine in that first dose must be
administered by 15 weeks of age, otherwise series not initiated
40-54
Reference
Reference
• Coverage estimates highly variable among WA counties
AI/AN
1.5 (1.29, 1.65)
1.7 (1.45, 2.04)
Asian
0.9 (0.86, 1.02)
0.4 (0.37, 0.50)
Black
1.3 (1.20, 1.41)
0.5 (0.43, 0.60)
Hisp/Latino
0.8 (0.70, 0.81)
0.4 (0.31, 0.41)
• The following maternal characteristics strongly associated
with 'partial' coverage: younger age; AI/AN, Black, or Pacific
Islander race; multiparity; ≤ high school education or some
college (compared to ≥ college degree); Medicaid use
Pac Islander
1.2 (1.06, 1.31)
0.6 (0.49, 0.74)
White
Reference
Reference
Primiparous
0.8 (0.74, 0.84)
0.9 (0.79, 0.94)
Previous live births*
1.2 (1.18, 1.24)
1.2 (1.14, 1.22)
Education ≤ High school 1.7 (1.63, 1.86)
1.1 (0.99, 1.19)
Some college 1.6 (1.46, 1.65)
1.2 (1.11, 1.31)
≥ College
Reference
Reference
Married
0.9 (0.83, 0.92)
1.2 (1.12, 1.31)
Medicaid
1.1 (1.05, 1.16)
1.1 (1.00, 1.17)
Univariate Comparisons
Predictor
Category
% Full
% Partial
Coverage Coverage
n=44,167 n=13,431
% No
RV5
n=4,999
<20
4.8
7.3*
5.2
20-29
47.4
55.7*
47.3
30-39
43.9
33.9*
42.6
40-54
4
3.1*
4.9*
AI/AN
1.6
3.4*
3.6*
• Records with no immunization data excluded (5,000)
Asian
8.6
5.3*
3.8*
• Inactive records excluded (5,202)
Black
4.8
7.6*
3*
Hisp/Latino
10.8
11.5*
5.1*
3.9*
2.2*
71.1
68.4*
82.4*
Primiparous
46.4
35.1*
36.9*
Previous live births+
0.9
1.3*
1.2*
≤ High school 30.5
50.9*
36.8
Maternal Predictors For ‘Partial’ or ‘No’ Coverage
Some college 29.7
31.6*
34.3*
• IIS records linked to 2010 birth certificate data
≥ 4yr College 33.5
17.5*
29.3*
Age
Methods
Rotavirus Vaccine Coverage Estimates
• IIS data extracted for all children born during 2010 (n=97,664)
Race
• Coverage groups assigned:
Full Coverage
Three doses RV5 by 8 months
Partial Coverage
One or two dose(s) RV5
No RV5 dose
(but ≥ one other dose between 6 - 15 weeks)
No vaccine dose (any) between 6 - 15 weeks
Pac. Islander 3.1
White
Education
• ‘No vaccine’ group excluded from analyses
Married
68.4
57.8*
71.1*
• Dataset restricted to records with WA birth residence and
complete data among variables of interest
Medicaid
36.3
49*
36.9
• X2 tests assessed univariate associations (Table 1)
• Odds ratios generated from multivariate model (Table 2)
• Analyses completed using SAS 9.3 and LinkPlus
* P-value < 0.05 when compared to ‘full’ coverage group
+ Continuous variable – mean expressed
• Among those with no RV5 dose, nearly 40% received
another vaccine between 6 - 15 weeks of age; unclear whether
vaccine was not offered or refused
1.4 (1.17, 1.78)
Race
N= 62,597 matched records from 2010 birth cohort
No RV5
Adjusted OR
(95% CI)
2.1 (1.85, 2.45)
No Vaccine
n=10,273 (11.8)
Table 1. Maternal risk factors expressed as
proportions among coverage groups
Partial Coverage
Adjusted OR
(95% CI)
• Partial coverage known to confer substantial immunity,
suggesting that 80.6% of 2010 birth cohort achieved some
immunity despite only 60% achieving ‘full’ coverage
<20
= outcomes of interest
= reference group
• Studies have found partial RV5 vaccination confers up to
85% protection (range: 69% - 85%)2,3
No Vaccine
Predictor Category
RV51
• WA State Immunization Information System (IIS) is a secure
web-based registry with 95% participation among vaccine
providers, covering 98% of VFC doses
No RV5
Table 2. Maternal risk factors among 'partial' and 'no
RV5' coverage groups compared to 'full' coverage group
N = 87,301
• Vaccines For Children Program (VFC) provides free vaccine
to all children ≤ 18 years in WA State and distributes the
RotaTeq (RV5) rotavirus vaccine
• Rotavirus vaccine coverage estimates for WA using IIS data
higher than NIS coverage estimates
Multivariate Results
2010 Birth Cohort (WA IIS)
• Prior to rotavirus vaccine introduction, one in 60 U.S. children
were hospitalized for rotavirus by age 5
Recommended schedule for
Dose 1
Dose 2
Conclusions
Discussion
* Odds for partial coverage and no RV5 increased by 20% with
each previous birth / older sibling
Rotavirus vaccine coverage among 2010 birth cohort by
county, WA State
• The following maternal characteristics strongly associated
with ‘No RV5’: AI/AN race; married; multiparity; some college
• Consistent with previously described risk factors for delayed
or no vaccine coverage, multiparity significantly associated
with 'partial' and 'no RV5' groups; odds increase with each
previous live birth
• Further studies needed to better understand reasons for no
rotavirus vaccine coverage
Limitations
• < 100% of WA vaccine providers participate in the WA IIS
• Since IIS initially populated with birth certificate data, unclear
whether those with no immunization data refused all vaccines,
see a provider who does not participate in IIS, or left the state
• Inactive records lack ‘date effective’ for inactivity, therefore
unclear whether these patients were active through rotavirus
vaccine time period so they were excluded
Acknowledgements
Phyllis Reed1, Belinda Baker1, Janna Bardi1, Sherry Riddick2,Yousif
Hozail2, Wayne Turnberg1, Natasha Close1, Kathryn MacDonald1,
Tracy Sandifer1, Erica Smith3
1 Washington
State Department of Health
2 Washington State Immunization Information System
3 Pennsylvania Department of Health
Kathleen Stigi, MPH
Epidemiologist
[email protected]
(206) 418-5586
This study was supported in part by an
appointment to the Applied Epidemiology
Fellowship Program administered by the Council
of State and Territorial Epidemiologists (CSTE)
and funded by the Centers for Disease Control
and Prevention (CDC) Cooperative Agreement
Number 5U38HM000414