Vaccine Rates High, but Measles On the Rise

Published: Sep 12, 2013
By Nancy Walsh, Staff Writer, MedPage Today
Full Story:  http://www.medpagetoday.com/Pediatrics/Vaccines/41569

Infant vaccine coverage remains high in the U.S. with targets near or above 90% being met for the recommended doses of measles, mumps, and rubella (MMR) vaccine, as well as for polio, hepatitis B, and varicella immunizations, a CDC report found.

A total of 90.8% of children had the appropriate MMR immunizations, 92.8% had the recommended three or more doses of poliovirus vaccine, 89.7% received three or more doses of hepatitis B vaccine, and 90.2% also had one or more doses of varicella vaccine, according to the Sept. 13 Morbidity and Mortality Weekly Report.

In addition, only 0.8% of children had received no vaccinations at all, Anne Schuchat, MD, of CDC, said during a telebriefing with reporters.

“These are really good results. We’ve come a long way in the 20 years since the Vaccines for Children program was established,” said Schuchat, who directs the National Center for Immunization and Respiratory Diseases.

The Vaccines for Children program was enacted in the face of a crisis in the years 1989 to 1991, when more than 55,000 cases of measles were reported in the U.S. and 123 people died.

“The hardest hit were unvaccinated preschool children living with low-income families. Their physicians were referring them to health department clinics for shots because they had no insurance, so as a healthcare system we were missing an opportunity to vaccinate children in their medical home,” she said.

Information was lacking at the time on the level of national vaccine coverage, because the survey tracking this had been canceled after 1985 because of budget cuts.

“So great improvement has been seen since then, but there’s still work to do,” Schuchat said.

Of particular concern is the rise in measles cases this year. Between Jan. 1 and Aug. 24, CDC received reports of 159 cases from 16 states. Almost all have been among individuals who either were unvaccinated or for whom immunization status was unknown.

“Philosophical objection” on the part of the parents was the most frequent reason given for failure to vaccinate, in 79%, while 13% were in children younger than 1 year who were not yet eligible for MMR vaccination.

A total of 37% of the cases were among children younger than 5 years, although the age range was from birth to 61 years.

Some 11% resulted in hospitalizations, and 4% had pneumonia.

Almost all of the cases resulted from imported infections, with half being linked to travel to Europe.

“Measles elimination has been maintained in the U.S. since it was declared in 2000. However, an estimated 20 million cases of measles occur each year worldwide, and cases continue to be imported into the U.S.,” the CDC report noted.

Three outbreaks were responsible for the majority of reported U.S. cases, with 58 from New York City, 23 from North Carolina, and 21 from Texas.

As to immunization rates overall, on a combined series endpoint of complete coverage for diphtheria, tetanus, and pertussis (DTaP), poliovirus, measles, varicella, Hemophilus influenzae type b (Hib), hepatitis B, and pneumococcal vaccine, the nationwide rate was 68.4%.

“For that series measure, I’d like to give a special shout out to Hawaii, which had the highest series coverage, at 80.2%,” Schuchat said.

Scoring lowest on the complete series measure was Alaska, at 59.5%.

However, some variance was seen according to socioeconomic status and by states.

For instance, 6.5% fewer children living in families with incomes below the federal poverty line had received four or more doses of the DTaP vaccine compared with children living in higher income families.

Also, 8.6% fewer had been given four poliovirus doses, 7.6% fewer had received the entire Hib series, and 6% fewer had received two or more doses of hepatitis A vaccine.

Vaccines that require boosters during the second year of life are particularly likely to be overlooked in lower socioeconomic groups, Schuchat noted.

In addition, 15 states had less than 90% coverage for MMR. “That’s a warning sign that measles outbreaks may occur or the state as a whole is becoming vulnerable,” she said.

These data were gathered in the random-digit National Immunization Survey (NIS), with written follow-up being sought from providers.

The 2012 survey was the first that included both landline and cell phones rather than just landlines, which may explain why some vaccination rates declined slightly.

For example, DTaP, polio, and hepatitis B coverage decreased by one or two percentage points between 2011 and 2012.

“Living in a household with only cellular telephone service is associated with poverty and other demographic factors that might be related to vaccination status,” the CDC report noted.

“The NIS sample now more closely resembles the U.S. population with respect to telephone service, and these 2012 vaccination coverage estimates should be considered a baseline against which subsequent trends in coverage can be evaluated,” the report stated.