When the Shaker family had their twins, they decided against immunizations.
"Immunizations don't seem very natural. So, I just wanted to stay away from them at least for a year," Melissa Shaker said.
But two months after bringing the boys home, baby Silas turned very pale.
"Like he looked like he was dying white. It was scary," she said.
"One of the first questions that was asked of her in the hospital was, 'Did you get the vitamin K shot?'" recalled Mark Shaker, Silas's father.
The Shakers hadn't. Silas had vitamin K deficiency and suffered multiple brain bleeds.
Typically, the blood clotting disorder affects only one in 100,000 babies, but Silas is one of seven cases Vanderbilt doctors have seen in the last year.
"Had we known some of these things, we could have made smarter decisions," Mark Shaker said.
"Thankfully, he was one of the cases that we'd seen after we'd already seen a couple of cases and so we gave vitamin K immediately to this child," said Dr. Robert Sidonio Jr., a pediatric hematologist at Vanderbilt University.
Sidonio said he believes the numbers could surge in the future because of the trend of parents refusing immunizations.
"Probably somewhere in the range of one in 100 to one in 1,000 kids will develop this," Sidonio said.
While doctors were able to stop the bleeding in Silas, he has to take medications for seizures and he's in physical therapy to retrain his left side.
"Only time will tell," Mark Shaker said. "You know, will he respond to therapy? Will there be any other residual side effects of this?"
To be safe, Silas' twin Abel was also treated and is doing fine.
Sidonio said many parents have declined the vitamin K shot because of a single study circulated on the Internet linking it to leukemia, but he said at least 10 studies since then have shown there is absolutely no link.