UNITED STATES - Kathleen Wiederman is not staunchly against vaccines. She simply believes it is better for her child to naturally battle an illness than to be vaccinated against it.
"Doctors don't know everything," said the 42-year-old recruiter, who prefers alternative medicine and gave birth at her home in the well-heeled Virginia suburbs without the aid of a pain-killing epidural.
At first, she and her husband agreed on the matter, but when their marriage ended, he pushed for their daughter to get some of her recommended vaccines and Wiederman relented.
Now her daughter is five and has had a handful of shots, including against chicken pox and measles, but not polio.
And if her child gets sick?
"Then we treat it however you need to treat it and work through it," she told AFP.
Wiederman, who has a law degree, is among a growing number of Americans who oppose vaccines, raising concerns about a resurgence in contagious diseases like measles and whooping cough.
Vaccine hesitancy is increasingly common, and not only when it comes to infant and childhood immunizations, experts say.
Two in three working age adults refuse to get the annual flu vaccine and the same proportion of parents decline the human papillomavirus (HPV) vaccine for young adolescents, according to the US Centers for Disease Control and Prevention.
"The people we are concerned about are the people who are hesitant. The general demographic is well-educated and upper middle class," said Barry Bloom, a professor of medicine at Harvard University.
"I think they are on the rise everywhere."
In recent years, reports linking vaccines to autism have been debunked, but fears of adverse events -- which experts say are rare -- have proven difficult to erase.
Some parents are troubled by the increasing number of vaccines children are given, which have risen from seven in 1985 to 14 today, a result of medical advances, according to the Centers for Disease Control and Prevention.
"I was stunned by the number of vaccines," said Alina Scott, a 37-year-old project manager and mother of a two-year-old son.
Scott said she began reading everything she could find on the topic, even before her child was born, and decided that vaccines were not for them.
"This lasted until about a year ago, when I just felt like I wasn't finding any new information. It's like I hit the end of Internet," she said. "I don't think we will be vaccinating any time soon."