National, State, and Local Area Vaccination Coverage Among Children Aged 19--35 Months --- United States, 2009

National, State, and Local Area Vaccination Coverage Among Children Aged 19--35 Months --- United States, 2009
Weekly
September 17, 2010 / 59(36);1171-1177

Since 1994, the National Immunization Survey (NIS) has been collecting data to monitor childhood immunization coverage. This report describes the 2009 NIS coverage estimates for children born during January 2006--July 2008 and focuses on the more recently recommended vaccines (i.e., hepatitis B [HepB] vaccine birth dose, hepatitis A vaccine [HepA], pneumococcal conjugate vaccine [PCV], and rotavirus vaccine) for children aged 19--35 months. The most recent NIS data indicate that vaccination coverage increased in 2009 compared with 2008 for HepB birth dose (from 55.3% to 60.8%) and HepA (from 40.4% to 46.6%), but coverage for PCV (≥4 doses) remained stable (80.4%). Full coverage for rotavirus vaccine was 43.9% among children born within 2 years of licensure (1). Coverage for poliovirus (92.8%), measles, mumps, and rubella (MMR) (90.0%), hepatitis B (HepB) (92.4%), and varicella (VAR) (89.6%) vaccines continued to be at or near the national health objective of 90%, although coverage for MMR and HepB vaccines decreased slightly in 2009. The percentage of children who have not received any vaccines remained low (<1%). Parents and primary-care providers continued to ensure that children were vaccinated, in spite of interim recommendations to suspend the booster dose of Haemophilus influenzae type b vaccine (Hib) because of a national shortage, and heightened public awareness of controversies in vaccine safety (2,3).

To estimate coverage for all age-eligible children, NIS uses a quarterly, random-digit--dialed sample of telephone numbers for the 50 states and selected urban areas and territories,* followed by a mail survey of the children's vaccination providers to collect vaccination information. Data were weighted to represent the population of children aged 19--35 months, with adjustments for households with multiple telephone lines, household nonresponse, and exclusion of households without landline telephones.† During 2009, the household response rate§ was 63.9%; a total of 17,313 children with provider-reported vaccination records were included in this report, representing 70.7% of all children with completed household interviews. Because the number of Hib¶ and rotavirus** vaccine doses required differs according to manufacturer, coverage estimates for these vaccines now take into account the brand of vaccine used. Logistic regression was used to examine differences among racial/ethnic groups, controlling for poverty status. Statistical analyses were conducted using t-tests based on weighted data and accounting for the complex survey design. All tests with p<0.05 were regarded as statistically significant.

During 2009, national coverage with the first dose of HepB within 3 days of birth (birth dose) increased to 60.8% from 55.3% in 2008, the largest increase observed for the birth dose in the past 5 years (Table 1); by state, coverage ranged from 22.8% in Vermont to 80.7% in Michigan (Table 2). Coverage with ≥2 doses of HepA vaccine increased from 40.4% in 2008 to 46.6% in 2009. Coverage ranged from 19.3% in Maine to 63.2% in North Dakota. Coverage with ≥4 doses PCV at the national level changed little (from 80.1% to 80.4%), but increased significantly in Illinois (from 76.2% to 82.9%), Mississippi (from 74.7% to 85.0%), Nevada (from 63.6% to 75.1%), and Wyoming (from 69.2% to 82.3%). Across all states, PCV coverage ranged from 67.5% in Missouri to 90.7% in Connecticut. Coverage for rotavirus vaccine was 43.9% nationally, similar to previous coverage reports for newly recommended vaccines, and varied widely by state, from 20.9% in Washington to 71.2% in Rhode Island. Rotavirus vaccine coverage increased from 8.0% among children born during January--June 2006 to 60.0% among children born January--June 2008. For children born between those periods, estimated coverage ranged from 34.8% for children born July--December 2006, to 49.0% for children born January--June 2007, to 53.4% for children born July--December 2007.

The seven-vaccine series (i.e., 4:3:1:3:3:1:4) reported in the 2009 NIS added ≥4 doses of PCV to the combined 4:3:1:3:3:1†† series reported in previous years. Because of changes in measurement of the Hib vaccine and the vaccine shortage that occurred from December 2007 to September 2009 (2), state coverage estimates included in this report were based on the series that excludes Hib. Using this modified seven-vaccine series (minus Hib), coverage remained stable in 2009 (70.5%) compared with 2008 (70.6%) (Table 1). In 2009, modified series coverage ranged from 56.2% in Missouri to 78.1% in Iowa (Table 2). Significant increases were observed in Wyoming (69.6% versus 58.9%), Idaho (70.5% versus 60.4%), Oklahoma (66.3% versus 57.4%), Nevada (62.6% versus 55.2%), and North Dakota (77.0% versus 69.1%). Among the 13 local areas, coverage ranged from 61.4% in the eastern/western counties of Washington to 73.5% in Los Angeles, California. The percentage of children aged 19--35 months receiving no vaccinations remained at 0.6%.

Coverage differed by race/ethnicity.§§ Among the more recently recommended vaccines, PCV and rotavirus coverage was lower among black and multiracial children than among white children (Table 3). Coverage for PCV also was lower among Asian children. Coverage for HepA was lower among black children and American Indian/Alaska Native children than among white children. Except for rotavirus coverage among black children, these differences persisted after controlling for poverty status. HepB birth dose coverage was higher among Hispanic children than among white children. For vaccines with longer-standing recommendations, differences were observed for diphtheria, tetanus toxoid, and acellular pertussis (DTaP) vaccine. Compared with coverage among white children, coverage was lower for black children for ≥3 and ≥4 DTaP doses and lower for Hispanic children for ≥4 doses only. The difference in coverage between white and black children for ≥4 doses remained statistically significant after controlling for poverty status.

Coverage also differed by poverty status.¶¶ Coverage for HepB birth dose was higher among children living below poverty level than for those living at or above poverty level (by 3.8 percentage points). Among children living below poverty level, coverage was lower for ≥4 doses of PCV (by 8.4 percentage points) and rotavirus vaccine (by 9.4 percentage points) than for other children. Among the longer-standing recommendations, coverage for ≥4 doses of DTaP also was lower (by 5.6 percentage points).

Reported by

KG Wooten, MA, M Kolasa, MPH, JA Singleton MS, A Shefer, MD, Immunization Svcs Div, National Center for Immunization and Respiratory Diseases, CDC.

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National, State, and Local Area Vaccination Coverage Among Children Aged 19--35 Months --- United States, 2009