Measles Journey Highlights Risk to Unvaccinated Kids

Minnesota outbreak began with a toddler traveling overseas, study says

MONDAY, June 9, 2014 (HealthDay News) -- A measles outbreak in Minnesota offers a case study of how the disease is transmitted in the United States today: An unvaccinated person travels abroad, brings measles back and infects vulnerable people -- including children who are unprotected because their parents chose not to vaccinate them.

That's the conclusion of a report published online June 9 in Pediatrics that details the 2011 outbreak that sickened 19 children and two adults in the state.

It began when an unvaccinated 2-year-old was taken to Kenya, where he contracted the measles virus. After returning to the United States, the child developed a fever, cough and vomiting. However, before measles was diagnosed, he passed the virus on to three children in a drop-in child care center and another household member. Contacts then multiplied, with more than 3,000 people eventually exposed.

Nine of the children ultimately infected were old enough to have received the measles-mumps-rubella (MMR) vaccine but had not.

In most of those cases, the child's parents feared the MMR vaccine could cause autism, according to researchers at the Minnesota Department of Health.

That idea -- first raised in 1998, by a British doctor named Andrew Wakefield -- has been discredited, said Pam Gahr, an epidemiologist who led the new research.

"But I think that as long as autism remains unexplained, the idea [that the MMR is a cause] will persist," Gahr said.

In the Minnesota outbreak, the child infected in Kenya was of Somali descent, as were most of the children whose parents had declined the MMR vaccine because of safety fears.

And that's consistent, Gahr said, with a striking decline in MMR acceptance among Minnesota's relatively large Somali population. In 2004, the number of Somali children in the state who were on schedule with their MMR topped 90 percent.

"By 2010, that was down to just 54 percent," Gahr said.

From what the health department learned in parent interviews, the decline seemed to stem from misinformation about an MMR-autism link.

Despite the unique circumstances of the Minnesota outbreak, though, measles can happen anywhere people are unvaccinated, said Dr. Andrew Pavia, chief of pediatric infectious diseases at the University of Utah in Salt Lake City.

"These outbreaks occur in all types of settings," said Pavia, who was not involved in the current study.

U.S. measles cases are at a 20-year high this year, the U.S. Centers for Disease Control and Prevention reported last week. As of May 30, the agency had received reports of 334 measles cases in 18 states.

Nearly all of the outbreaks involved unvaccinated people who brought measles back after a trip overseas, the CDC said.

The hardest-hit state is Ohio, where people in several Amish communities were infected after unvaccinated missionaries traveled to the Philippines and carried the measles virus back.

Amish communities have historically had low vaccination rates. And a 2011 survey of Amish parents who refused to vaccinate found that nearly all cited safety fears.

According to Pavia, the safety concerns of parents in the Minnesota outbreak illustrate the "power of bad information."

The MMR-autism link proposed by Wakefield was later found to be based on fraudulent data, and many studies since have found no connection between the vaccine and autism.

"Wakefield has been thoroughly debunked," Pavia said.

Gahr noted that these days, most parents never had or even saw a case of the measles. So some might dismiss it as just another childhood infection, she said.

But measles can prove serious, or even deadly. About 30 percent of people with measles develop a complication such as ear infection, diarrhea or pneumonia, the CDC says. Among children, one in 1,000 suffers brain inflammation, and one or two out of every 1,000 die.

"Even if you don't develop complications," Pavia said, "the disease is miserable."

Measles typically begins with a fever, cough, runny nose and "pink eye." After several days, a rash emerges around the face and neck, then spreads to the rest of the body.

"The thing is, we have the power to prevent it," Pavia said.

In the case of the Minnesota outbreak, he added, "the first infection that spread in the community was misinformation. The second was measles."

SAFER TO GIVE MMR AND CHICKEN POX VACCINES SEPARATE FOR FIRST DOSE, RESEARCHERS SAY

MONDAY, June 9, 2014 (HealthDay News) -- Toddlers who get a newer vaccine that fights four infections in one jab have a slightly increased risk of fever-induced seizure, a large new study confirms.

At issue is a vaccine that targets measles, mumps, rubella and varicella (chickenpox) in one shot, instead of giving the traditional MMR and varicella vaccines separately.

In theory, one shot sounds better than two. But in the new study, 1-year-olds who received Priorix-Tetra -- the MMRV vaccine used in Canada -- were twice as likely to develop a fever-related seizure as children who got separate MMR and chickenpox shots.

The findings are in line with a 2010 study of the MMRV vaccine used in the United States, known as ProQuad.

In the United States, parents now have to explicitly ask for the MMRV if they want their toddler to have it, said Dr. Nicola Klein, who led the ProQuad study.

But even with the increased risk posed by the MMRV vaccine, the odds of a brief, fever-related seizure are extremely low.

And the seizures aren't dangerous, "though they are scary for parents," said Klein, co-director of the Kaiser Permanente Vaccine Study Center in Oakland, Calif.

She said children are actually much more likely to suffer a high fever and seizure if they were to catch the measles.

"Get your child vaccinated," she stressed. "We're in the middle of a 20-year high in measles cases."

Fevers are part of the immune system response, whether to infection or vaccination.

It's not clear why the MMRV is more likely to cause a fever-related seizure than the separate shots, said Shannon MacDonald, a post-doctoral fellow at the University of Calgary in Alberta, Canada, who led the new study. But one theory maintains the combined vaccine triggers a stronger immune response and a higher fever in some children, which makes a seizure more likely.

MacDonald's findings, published online June 9 in CMAJ (Canadian Medical Association Journal), are based on records for almost 278,000 Alberta children between the ages of 12 and 23 months. The children received either the MMRV or separate MMR and chickenpox shots on the same day.

Overall, the study found, children's seizure rate peaked seven to 10 days after they were vaccinated. At that point, there were almost six seizures for every 10,000 doses of the MMRV, versus two seizures for every 10,000 doses of the separate vaccines.

"You see the same increase in risk with these different formulations," said MacDonald, referring to the Priorix-Tetra and ProQuad vaccines.

The traditional approach -- separate MMR and chickenpox vaccines -- seems safer.

"There's no question children should be vaccinated," MacDonald said.

As of May 30, the U.S. Centers for Disease Control and Prevention had received reports of 334 measles cases in 18 states. Nearly all have involved unvaccinated U.S. residents who traveled to countries where measles is common, then brought the virus home with them.

Besides causing misery -- fever, cough, and a body-wide rash -- measles infection can lead to serious complications. Up to 5 percent of infected children develop pneumonia, the CDC says, while one in 1,000 suffers brain inflammation. And for every 1,000 children who develop measles, one or two will die.

But parents should be aware that the MMRV carries a higher seizure risk and discuss that with their pediatrician, MacDonald said. Some parents may still want the combined shot, to spare their child from two needle jabs, she added.

Based on the ProQuad study, the U.S. Advisory Committee on Immunization Practices changed its stance on the MMRV. Now it says that unless parents ask about the combined vaccine, doctors should default to separate shots for young children getting their first dose of the MMR and chickenpox vaccines.

The story is different, though, with the second dose, typically given between the ages of 4 and 6 years. In general, fever-related seizure is uncommon at those ages, and the advisory committee says the MMRV is the better option.