Liz Pinkey and husband Stephen Behun III's decision to vaccinate their three children had its roots in a teacher's remark and babies' headstones.

Pinkey once wrote a paper on childhood diseases her teacher said would educate her classmates about illnesses they had never heard of, like measles, mumps, pertussis and diphtheria.

Pinkey knew about them, from reading Laura Ingalls Wilder's stories of the old days. Later, classes in immunology and virology prompted her to earn a degree in biology.

"I didn't learn about how vaccines worked from the 'lame-stream media' or the insert in a pharmaceutical company's product," she said. "I learned about it in a lab, from experts in the field. Because I still liked 'olden times,' I also got a degree in history. Maybe it's this dual degree that leads me to believe that one of the greatest technological advances of the 20th century was the widespread use of vaccines.

"Perhaps it was growing up with memories of my grandmother telling me horror stories about children she grew up with contracting polio, or my affinity for walking through old cemeteries searching for clusters of tiny headstones in family plots that all had roughly the same date on them, or understanding the basic biology of how a person develops immunity and how critical herd immunity is to protect those who can't be vaccinated because they are too young or too sick or otherwise compromised, or the long conversations I had with the medical professionals who treat my children, outlining the pros and the cons of vaccinating," she said. "Actually, it was all of those things, because I believe in gathering factual information and data checking before making major medical decisions."

But the biggest influence is something far more precious.

Parents' decisions to not vaccinate probably won't affect their own children very much.

"However, their decision may be fatal for someone else. Someone who is too young or too sick to get the vaccination will be the one to suffer instead," she said.

"I have a child who has a severe congenital heart defect. While we have been very blessed to have him be relatively healthy and robust, we have had several instances of some illnesses that should have been prevented by his vaccinations.

"In each case, his symptoms were mild. His doctors have surmised that although his immune system is functioning, it may not be functioning at 100 percent. Due to his heart condition, any illness he contracts places an extra strain on his system," Pinkey said.

Eventually, the family may need to consider a heart transplant.

"At that point, his exposure to any sort of illness would be critical. He is depending on his herd to protect him," Pinkey said.

"Now I fear that the nonvaccinators will in fact get what is coming to them and then, they will share it with him."