Forty-five students, staffers and others associated with Ohio State University are at the center of a mumps outbreak this week. It is suspected that the highly contagious disease has spread to more than 18 other people not affiliated with the school. Local preschools have been advised on how to minimize the risk of transmission, since young children are most at risk.
"A lot of the problems is that parents will take the kids out on the weekends and they will expose them to germs that we don't have here at the school," said Coleen Barber, a local preschool director.
Mumps is a rare disease in the U.S. However, in 2006 there was a multistate outbreak of 6,500 cases, and in 2009 there was another outbreak, with 4,000 cases. Since the introduction of a vaccine in the 1960s, mumps cases have dropped by 98 percent in the U.S.
Measles cases are also on the rise. At least 53 people in 10 states have been infected with the disease this year, even though it was close to eradication in the U.S. just a decade ago.
Texas public health official Russell Jones warns, "With measles, you can have an incubation period from the time you are exposed to the time you get sick, anywhere from 10 to 21 days. You become infectious four days before a rash onset. During those four days, you may not feel bad."
Measles is very contagious and can live in the air two hours after an infected person has left the area. Common symptoms are fever, coughing and rashes.
Last month in New York, some 20 cases of measles were reported in upper Manhattan and the Bronx. The state's health commissioner says it may have gained speed in hospitals where those being treated were not immediately quarantined.
"Measles is so incredibly infectious, it’s probably the most infectious of all infectious diseases," said Dr. Thomas Frieden of the Centers for Disease Control and Prevention.
"And even though we have high vaccination rates overall, there are pockets of people who haven't taken vaccination."
The anti-vaccination movement in the United States is large and diverse, consisting of politically or religiously conservative, health-conscious or autism-fearing parents.
U.S. anti-vaccine movement
Deeply conservative parents may feel requiring vaccination is a government intrusion into parenting
Some orthodox religious parents do not believe in man-made vaccines
Some well-educated, Internet-savvy and health-conscious parents see vaccines as unhealthy and unnatural
Some parents fear immunization is linked to autism, on the basis of a 15-year-old report that has since been debunked
Some high-profile politicians and celebrities have questioned vaccines and their use. One of the most vocal celebrities is Jenny McCarthy, a co-host of TV's "The View." She links her son's autism to his measles, mumps and rubella shot and says he has been cured through a gluten-free diet and alternative medicine.
Parents who do not vaccinate their children often feel their children are protected through herd immunity. If most people in a community are vaccinated against diseases, those illnesses are unlikely to spread in the group and strike the unvaccinated. Herd immunity requires high vaccination rates, upward of 80 percent; some communities in the U.S. are struggling to achieve such rates.
According to a recent study funded by the CDC, nearly half of American children born from 2004 to 2008 were not up to date on their shots.
The World Health Organization warns that if measles vaccinations were to stop worldwide, as many as 2.7 million people would die annually from the disease.
What's behind previously rare disease outbreaks?
How much of a role does the anti-vaccination movement play?
How can parents and government prevent outbreaks?
We consulted a panel of experts for the Inside Story.
With measles … you become infectious four days before a rash onset. During those four days, you may not feel bad.
Texas public health official
This panel was assembled for the broadcast of “Inside Story.”
For future hard-hitting conversations, find Al Jazeera America on your TV.