What to know about measles
Measles is described as the world's most contagious disease, with nearly every unvaccinated person who comes into direct contact with an infected person becoming ill. The most common symptoms are fever, rash, and cough. However, some cases can develop pneumonia, hepatitis, and brain swelling.
Greg Poland, professor of medicine and infectious diseases at the Mayo Clinic, doesn't mince words about the dangers of Measles. "Children die as a result of this disease," he says, noting that in the early 1990s measles was fatal in approximately three in 1,000 children.
What is behind the comeback?
Although it is too early to know whether the California outbreak will surpass other large outbreaks in recent years, public health officials say that measles seems to be making a comeback.
Although the vaccination rate for measles remains high overall, pockets of unvaccinated people have formed that make some communities vulnerable. A Kaiser Permanente study released this month found that at least five communities in Northern California had low rates of vaccination. Vallejo, a city near San Francisco, had a vaccination rate of approximately 75%. (For context: Medical experts say that between 92% and 95% of children should receive two doses of the measles, mumps, and rubella (MMR) vaccine to maintain herd immunity against measles.)
In 2014, CDC reported a sharp spike in measles cases, with 644 cases across 23 outbreaks.
"In some sense the success of our immunization program is its own enemy," says Walter Orenstein, associate director of the Emory Vaccine Center at Emory University. He argues people have become complacent because they haven't seen the disease in decades.
Orenstein says his "biggest fear is we will re-establish transmission and have many more cases." Currently, he is heading the National Vaccine Advisory Committee to devise strategies for increasing vaccine acceptance. Tracy Lieu, who worked on the Kaiser study, agreed that more outreach to communities with low vaccination rates is needed. "We need to figure out how to better meet parents' needs," she says.
Clinicians may also need a refresher, experts warn. In terms of training, "It's not something you spend a great deal of time on at all, for obvious reasons," says William Schaffner, an infectious disease specialist at Vanderbilt University Medical Center. "If you haven't seen it before, it can be puzzling."
James Cherry, a UCLA research professor, says measles is especially easy to miss because it presents in the same way as other common illnesses in its early stages. But several days after the initial symptoms, doctors can look for so-called Koplik spots inside the cheek, and then later a telltale rash.
Unfortunately, some think the best preparation is experience. Paul Offit, a physician and advocate for immunization, says, "You can read about it, but there's nothing like seeing it."
The takeaway: Doctors should be on the lookout for possible cases of measles, which may be resurging because of pockets of unvaccinated people that appear to have corroded herd immunity in some communities.