But there's one graph the former CEO of Hewlett-Packard and presidential hopeful should see.
In the U.S., the number of cases of measles, a highly contagious viral illness that causes fever, a red rash and, in serious cases, blindness or even death, has made a comeback in recent years, in part because more parents in states with lax vaccination laws are not having their children immunized.
As the graph from the Centers for Disease Control and Prevention shows, the number of vaccine-preventable cases of measles in the U.S. spiked last year. The majority of people sickened by the virus were not vaccinated, the CDC reported. Health experts have blamed the new illnesses on the growing trend of parents opting not to vaccinate their children.
A parent's choice: During a town hall on Thursday in Alden, Iowa, Fiorina said California lawmakers made a "mistake" when they voted earlier this year to ban immunization exemptions for religious reasons. "California is wrong on most everything, honestly," Fiorina said, according to Time. "I'm not at all surprised that they made that mistake as well."
She said when it came to vaccinations, "It's always the parent's choice."
The GOP candidate did however concede that schools could choose to deny a child's attendance should they not be vaccinated.
"When you have highly communicable diseases where you have a vaccine that's proven, like measles or mumps, then I think a parent can make that choice, but then I think a school district is well within their rights to say, 'I'm sorry, your child cannot then attend public school,'" Fiorina said.
It's a position the Republican White House contender has taken in the past. A month after a measles outbreak hit Southern California, prompting public health warnings and sparking a debate about the safety and efficacy of statewide vaccination programs, Fiorina told BuzzFeed she thought parents "have to make choices for their family and their children."
"I think vaccinating for measles makes a lot of sense," she told BuzzFeed. "But that's me. I do think parents have to make those choices. I mean, I got measles as a kid. We used to all get measles... I got chicken pox, I got measles, I got mumps."
Other candidates take a stand against vaccines. Fiorina isn't the only candidate to come out against mandatory vaccinations.
Wisconsin Gov. Scott Walker said such choices should be left up to individual states. "It's up to the states, and all the states right now have a rule," he said in February, according to the Milwaukee Journal-Sentinel. "The only difference is, state by state, some have no leeway, some have some flexibility. But everybody has a law on the books."
Sen. Rand Paul (R-Ky.), in an interview with Laura Ingraham earlier this year, stated that he's "not anti-vaccine" but "for the most part it ought to be voluntary."