Last week, the U.S. Centers for Disease Control and Prevention (CDC) announced that the U.S. has seen more cases of measles than at any time since 1996 in the last six months—and its stories like that that have caught the attention of actress Amanda Peet, among others concerned about the resurgence. In Europe and the U.K., children are dying of measles. Declared eliminated in the U.S. in 2000, and as recently as the early 1960s, as many as 500 children in this country died every year from the viral disease, characterized by a red rash and highly infectious cough.

The first outbreak of 2008 came via a 7-year-old boy from San Diego, who traveled to Switzerland with his family. He had not been vaccinated and contracted measles, which he subsequently passed on to schoolmates, infants at his doctor's office and children around him in the hospital.

Despite a visible rash, he had not been quarantined at the hospital or doctor's office. "They're not seeing measles anymore," says Jane Seward, deputy director of the division of viral diseases at the CDC. "They have forgotten about the severity."'s David Biello spoke with Seward about the 131 cases that have occurred through July.

SA: How dangerous is measles?

JS: Anyone with a rash illness that's compatible [with measles] needs to be isolated the minute they are seen. People have forgotten what measles looks like and have forgotten how infectious it is…

Back in the early part of the century, it killed thousands of people a year. The biggest year was 10,000. Over the years, those deaths declined but in the 1960s, right before the vaccine was developed, it killed 400 to 500 children every year out of 500,000 reported cases at that time. Three to four million cases actually occurred, because not all cases get reported.

Of those 500,000 reported cases, there were 4,000 cases of encephalitis a year. That's brain infection and can have some serious sequellae, like retardation and things like that. Measles can also cause pneumonia…

Some parents think that American medical care is such that it can treat any complication on measles. They're not right on that. Medical care is the same as the 1960s in terms of encephalitis. There's very little that can be done to alter that outcome. And there is no treatment for measles as such. There are no antivirals to use.

SA: Why are so many cases coming out of Europe?

JS: In the U.K., they've seen a decline in their vaccine coverage because of autism concern. They have now announced that there is endemic transmission of the disease in England. The situation there is parents choosing not to vaccinate.

Some of the countries in Europe, they never achieved as high vaccination coverage as we did. Europe doesn't do as good a job with vaccine coverage. There's an outbreak in Austria and Germany with up into the hundreds of cases.

Israel has a very similar amount of vaccine coverage as the U.S. but they are experiencing an outbreak. That's in a community that is opposed to vaccination. You can have sizable communities that oppose vaccination and that can lead to much bigger outbreaks.

It's keeping us on our guard. We do continue to have imports, there was another one from Italy identified [in the last few days.] Italy is really hopping with measles. We're going to be watching closely as people come back from Beijing. There was one case from China this year but also mixing with travelers from other countries in China.

SA: Is vaccination in the U.S. declining?

JS: The 2007 numbers are going to be released soon so I can't give you those. What I can say is, we are not concerned. But those numbers reflect practice from a few years ago.

SA: How infectious is measles?

JS: It's the most highly infectious virus there is. If you have 100 unvaccinated people in a room and a person with measles walks in and coughs, 90 people or more will get measles. It's just very, very infectious. Coughing will aersolize the virus.

SA: Does this mean the other diseases in the vaccine package—mumps and rubella—will also make a comeback?

JS: Measles is the sentinel. It's highly infectious, pretty easy to recognize and confirm with lab tests.

Rubella vaccine is very effective and rubella is not as contagious as measles. You only need one dose of rubella vaccine for very high effectiveness and most people get two. We haven't seen an increase in rubella.

Mumps had a large outbreak in 2006. We are not sure if we eliminated it like measles and rubella. It wasn't because of people coming back from overseas although the virus did come from overseas. The mumps vaccine is just not as effective and this happened in vaccinated kids, kids in college.

SA: What advice do you have for parents who are concerned about vaccinating their child?

JS: I encourage them to talk to their physician and get the best available information on what they are concerned about. There is a lot of misinformation on the web. We all use it a lot, but there's a lot of misinformation there.

This vaccine has never contained thimerosal [a mercury-derived preservative linked by some to autism.] We don't consider that involved in causing autism but thimerosal was not included [in the measles vaccine].

It's a difficult decision for parents, I understand that. They want their children to be healthy and safe. Measles remains a risk.