Measles numbers multiply, myths linger

Two cases of measles, the highly contagious virus, have been confirmed just outside of Boston, according Massachusetts Department of Public Health. Later reports traced the disease to a Framingham Trader Joe’s shopping market.

And while most people in the United States have received vaccines against the disease, or got it and recovered as children making them immune, health officials are advising anyone displaying any symptoms to call a doctor. (It’s not recommended you go to a health care facility, out of fear you may infect others who have not been vaccinated.)

Many adults associate measles with mild illness and relatively harmless red spots. Not quite, says Ronald Samuels, MD, MPH, associate medical director of Boston Children’s Primary Care Center. “Measles is different from chicken pox. A mild case of measles doesn’t exist.” That message takes on a new urgency in light of data released by the Centers for Diseases Control and Prevention (CDC), which tallied 159 reported cases of measles from January 1-August 24 of this year.

The U.S. declared measles eliminated with no cases of continuous transmission for 12 months or longer in 2000. Since then, the number of annual cases has ranged from 37 to 220 in 2011. The current numbers suggest a potential problem.

The uptick isn’t huge, but could signal that the U.S. is on track to follow the path of England, which saw measles cases swell from 188 in 2004 to 2,030 in 2012. England has since launched an MMR immunization catch-up program to target previously unvaccinated children in an attempt to contain the spread of measles.

Immunization: wonders and woes

Measles immunization is recommended for children between 12 to 23 months of age with a booster between ages 4 and 6 years. Nationally, 91 percent of children are immunized. In Massachusetts, 93.7 percent are immunized.

“The problem is the pockets of unimmunized children,” says Samuels. Parents have limited experience with this disease, and their knowledge is restricted to rare side effects of the vaccine. “They and their neighbors scare each other and forego vaccinating their children.”

Measles is a highly contagious, potentially fatal disease, responsible for 158,000 deaths worldwide in 2011.

Possible mild side effects of the vaccine include fever, mild rash and swelling of the glands in the cheek or neck. Seizure occurs in 1 out of 3,000 doses, and a temporary low platelet count occurs in 1 out of 30,000 doses. Severe allergic reactions are extremely rare at less than 1 in 1 million doses.

One of the most oft-touted reasons for foregoing immunization is the unproven connection between MMR and autism, a fallacy which spread in 1998 when The Lancet published a study that claimed the MMR vaccine could contribute to the development of autism. Ten of the 13 authors of the paper have withdrawn support for the study, and the journal has retracted it. Nevertheless, the false link is particularly troubling for parents with an older autistic child.

It’s not uncommon for parents to want to delay vaccination for a second or third child if an older sibling has autism. “I used to tell them we could discuss it next year,” says Samuels. The CDC data indicating measles may be on the rise has prompted him to change his advice and recommend on-schedule immunization.

Parents may not realize measles is a highly contagious, potentially fatal disease, responsible for 158,000 deaths worldwide in 2011.

Another misconception about measles relates to geography. When most parents and community members worry about the transmission of vaccine-preventable diseases, they think of diseases that originate in Africa, India or China.

Not so with measles, with Europe serving as the primary gateway to imported disease in the U.S. The disease can infect an unimmunized child via a traveler visiting from Europe or via a local resident who acquires an infection in Europe.

Hanging with the herd

The MMR vaccine is contraindicated for very few children. The exceptions are limited to kids with serious health issues like cancer or an allergy to a vaccine component. Even these children can be afforded some protection from the vaccine via the concept of herd immunity.

That is, when most members of a community are vaccinated (and protected) from a disease, the disease can’t catch hold and turn into an outbreak. A few individuals might contract measles, either because of a rare vaccine failure or because the individual was not vaccinated. If most of the community (or herd) is vaccinated, the disease dies out. In contrast, in an unvaccinated community, the disease spreads, with potentially fatal consequences for unvaccinated children.

The upshot is simple, says Samuels. “All children should be vaccinated.”

Do you have questions about where to get your child vaccinated? Use the HealthMap Vaccine Finder, developed by Boston Children’s HealthMap team, for all of your child’s vaccination needs.