Vaccines are not without risks.
The federal government maintains a Vaccine Injury Compensation Trust Fund that has paid out $2.4 billion for nearly 3,000 vaccine injury claims since 1989.
While the dollar figure is high, the number of compensated vaccine injury claims represents a minuscule portion of the millions and millions of children who have been vaccinated during that time.
The federal government has never concluded that any vaccine caused autism, although one family of an autistic child was awarded $1.5 million.
In that 2008 case, the federal government agreed that vaccines injured then-9-year-old Hannah Poling, a Georgia girl who developed symptoms of autism after receiving several vaccinations in one day. A panel that reviewed Hannah's case said the vaccines had aggravated an underlying medical condition, a cellular disorder, and brain damage resulted.
The federal government contends the damages, plus $500,000 in annual care, that it awarded to Hannah's family are not an acknowledgment that vaccines cause autism, though many people saw them as validation of a link.
The government does maintain a table of possible injuries that could result from certain vaccines. They range from severe allergic reactions to seizures to death.
There have been 1,086 claims of deaths caused by a vaccine since 1989. More than half of the death claims were compensated - 54 percent. Another 23 percent were dismissed, but plaintiffs were awarded attorney's fees. Nearly 19 percent were dismissed with no compensation and 4 percent are still pending.
The vaccine compensation fund refused to release the number of deaths by year - which the Star requested for analysis - contending it would take too much staff time.
A 2011 analysis by the Institute of Medicine, an independent, nonprofit group of U.S. physicians and researchers, reviewed more than 1,000 research articles and concluded that few health problems are caused by or clearly associated with vaccines. A committee of institute experts found "convincing evidence" that 14 health outcomes - including seizures, inflammation of the brain and fainting - can be caused by certain vaccines. But it found such outcomes to be rare.
The committee found less clear data on associations between specific vaccines and other effects, including allergic reactions and temporary joint pain.
In addition, the evidence showed no links between immunizations and some serious conditions including Type 1 diabetes and autism, despite parents' suspicions.