Three-Fold Increase in Measles Warrants Vigilance, CDC Says

December 05, 2013

A 3-fold increase in US measles cases in 2013 highlights the need to overcome fear of vaccination in this country and vanquish the deadly virus in other countries so it cannot spread here, the head of the Centers for Disease Control and Prevention (CDC) said today.

Public health authorities have made tremendous progress in controlling measles, but "we're not anywhere over the finish line," said CDC Director Thomas Frieden, MD, MPH.

The call to vigilance comes on what otherwise is a red-letter day in the war against measles. A CDC study published online today in JAMA Pediatrics reports that the elimination of measles in the United States as confirmed in 2000 was sustained through at least 2011. The study defined "elimination" as the absence of endemic disease transmission — meaning continuous transmission for 12 or more months — in a particular geographic area. During that period, the nation experienced a median 61 cases a year, a tiny fraction of the estimated 4 million Americans who caught measles annually before a vaccine was introduced in 1963.

In 88% of the cases from 2000 to 2011, the virus originated from outside the United States. No one could pin down the source in the remaining cases. Two in 3 individuals who got the measles were unvaccinated. For another 20%, vaccination status wasn't known.

The United States also has been free of endemic rubella and congenital rubella syndrome from 2004 through at least 2011, according to the CDC study.

"Any Virus Is Only a Plane Ride Away"

At the press conference today, Dr. Frieden said the measles vaccine, which was eventually combined with vaccines for rubella and mumps, has saved the lives of at least 30 million children worldwide since its introduction. However, the United States and the rest of the world cannot rest on its laurels. Dr. Frieden pointed to 175 reported cases of measles in the United States so far in 2013, nearly triple the median from 2000 to 2011. In almost all the cases, someone travelling into the United States brought in the virus, and roughly 90% of the people who caught it either had been unvaccinated or not vaccinated on time.

Parents refusing vaccination for their children on religious or other grounds figured prominently in the 3 largest measles outbreaks of 2013, which occurred in New York City, North Carolina, and Texas, where the virus spread among members of a church taught to distrust vaccination. "It's not a failure of the vaccine, but a failure to vaccinate," said Dr. Frieden.

On the 50th anniversary of the measles vaccine, Dr. Frieden took time during the press conference to honor Samuel Katz, MD, one of vaccine's creators. "That vaccine has been one of the greatest accomplishments not only of science and medicine, but of humankind," said Dr. Frieden.

Dr. Katz, an emeritus professor of pediatrics at Duke University, acknowledged pockets of resistance to his vaccine both here and in Western Europe.

"I don't think we're ever going to change their minds," he said. "These are people who are very rigid in their approach. If we can get 95% of children vaccinated, those others will be passively protected."

Dr. Frieden said vaccination rates have been high enough to keep measles outbreaks small and relatively short-lived, but "vaccination requires continuous effort." The reluctance of some Americans to have their children vaccinated, he said, represents "a significant threat."

"In some ways, vaccination becomes the potential victim of its own success," he added. "The diseases we're vaccinating for are no longer so common. It can lure us into a sense of complacency. But measles can be deadly.

"We need to both ensure that we keep our own guard up, and work with [the World Health Organization] and partners around the world to drive the [number of cases] down to protect not only those countries but ourselves as well.

"Any virus is only a plane ride away. We are truly interconnected."

The CDC has made a substantial investment in the international war on measles, according to the agency study published in JAMA Pediatrics. From 2000 to 2011, the CDC spent almost $440 million on global measles control. Some of the money went toward 200 million doses of vaccine and technical assistance in developing nations.

The authors of the study in JAMA Pediatrics have disclosed no relevant financial relationships.

JAMA Pediatr. Published online December 5, 2013. Full article


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