As a growing outbreak of measles causes concern and fear, parents are reacting in a number of ways.
Some are taking extra steps to safeguard their children, while others are fighting back against new laws meant to stop the spread of infectious diseases.
While around 700 protesters concerned about the potential side effects of vaccines picketed in Washington state to oppose new restrictions on opting out of mandatory vaccinations, the Centers for Disease Control and Prevention confirmed there are 101 cases of measles in 10 states.
The health department says that almost all of the cases are in children who have not been vaccinated, or who have not received both doses of the measles vaccine.
Health experts say the vaccine is 97% effective at preventing measles after taking both doses.
As the outbreak spreads, some teenagers are taking a surprising step to protect themselves: getting vaccinated without their parents' permission.
The teens, whose parents chose not to vaccinate them against measles, chickenpox or other contagious diseases as children, are defying their wishes by getting vaccinated on their own.
News reports have even tracked some searching for health advice - and tips on sneaking behind their parents' back - on social media.
In certain states, like Oregon, teenagers 15 or older can get vaccinated at no charge through the state's Medicaid program.
The Washington Post profiled 18-year-old Ethan Lindenberger, from Ohio, who asked strangers on Reddit, "My parents are kind of stupid and don't believe in vaccines. Now that I'm 18, where do I go to get vaccinated? Can I get vaccinated at my age?"
The answer turned out to be yes, and Lindenberger has since been vaccinated for measles and a host of other diseases, after doing his own research and deciding that vaccines are safe.
Lindenberger's mother, Jill Wheeler, told the online magazine Undark that her son's decision "was like him spitting on me, saying 'You don't know anything, I don't trust you with anything. You don't know what you're talking about. You did make a bad decision and I'm gonna go fix it.'"
Wheeler said she chose not to vaccinate her son out of concern that vaccines, including the one for measles, mumps and rubella, could cause autism - which has never been proven, as the only study claiming it does has since been retracted.
Teens like Lindenberger aren't the only ones rushing to get their shots in the wake of the outbreaks. Washington's Health Department says more than 3,000 people were vaccinated against measles in January, a huge jump from the same month last year when about 530 people got the same shot.
Measles, a contagious disease caused by a virus, was thought to be completely wiped out in America in 2000. But large groups of vaccinated patients have lead to new outbreaks from cases outside the U.S. since then.
Symptoms include a body-wide rash, fever, cough, and sometimes deadly inflammation of the brain.