More than three-quarters of the nation's young children have been immunized with the full series of childhood vaccines recommended by the Centers for Disease Control and Prevention, according to data from the CDC's 2007 National Immunization Survey.
The survey provides coverage estimates for the 4:3:1:3:3:1 immunization series for children aged 19–35 months that includes vaccines for diphtheria, tetanus, and acellular pertussis (DTaP); poliovirus; measles, mumps, and rubella (MMR); Haemophilus influenzae type B; hepatitis B; and varicella.
All but one vaccine in the recommended series—the fourth dose of the DTaP vaccine—reached 90% coverage in 2007, including for the first time the varicella vaccine and the third dose of the seven-valent pneumococcal conjugate vaccine (PCV7), Dr. Julie Gerberding, director of the CDC, reported in a media briefing on the survey results. Additionally, less than 1% of the more than 17,000 children born between January 2004 and July 2006 represented in the survey had not received any vaccines in the recommended series by ages 19–35 months, and there were no statistically significant decreases in individual vaccine coverage from 2006 to 2007 (MMWR 2008;57:961-6).
The coverage rates are indicative of the “ongoing success” of the country's immunization program, said Dr. Gerberding. “This annual report card is very good. The survey indicates that we are at or above our Healthy People 2010 goal of 90% coverage for each of the vaccines [in the 4:3:1:3:3:1 series], and at 77.4%, we are close to the target of 80% for the combined series.” These numbers are a reflection of “the trust that parents have in the safety of the vaccines and in the health care providers who administer them,” she said.
Relative to the 2006 survey data, coverage levels in 2007 for one dose of the varicella vaccine increased from 89% to 90%, and coverage levels for three or more doses of the PCV7 increased from 87% to 90%, Dr. Gerberding reported.
As in previous years, the estimated vaccine coverage rates for the 4:3:1:3:3:1 series varied substantially among states, ranging from a low of 63% in Nevada to a high of 91% in Maryland. Similarly, there was substantial variation among 14 local areas surveyed, ranging from 70% in San Bernardino County, Calif., to 82% in Philadelphia, she said.
Despite regional coverage gaps, said Dr. Gerberding, “vaccine coverage levels were similar across all racial and ethnic groups for the complete series, and there were some important gains.” Specifically, among Native American and Alaska Native children, both varicella and fourth-dose PCV7 coverage increased significantly, from 85% in 2006 to 95% in 2007 for varicella and from 63% in 2006 to 80% for PCV7 in 2007, she noted.
Belying the apparent successes in the immunization program is the recently reported surge in U.S. measles outbreaks (MMWR 2008;57:893-6), which is “a sobering aspect in our failure to protect some children from vaccine-preventable diseases,” said Dr. Gerberding. “Many of the children affected in these outbreaks were not adequately protected. Some were too young to be fully immunized, and some parents chose not to immunize their children.”
The measles outbreaks serve as an important reminder to maintain heightened vigilance “and not take the benefits of immunizations for granted,” said Dr. Anne Schuchat, director of the CDC's National Center for Immunization and Respiratory Diseases. “We're doing well, but we're not finished. Achieving high [coverage] levels is important for preventing major resurgences in diseases like measles.”
The measles outbreaks also point to some of the limitations of the National Immunization Survey data, Dr. Schuchat said during the briefing.
The survey estimates state and national coverage levels and provides information on specific local areas, “but we don't have information for every local area,” she said.
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