In 1998, the respected medical journal The Lancet published a study by Dr. Andrew Wakefield that caused an uproar. The article presented evidence of a link between the MMR (measles, mumps, rubella) vaccine and autism in children. In fear, some parents chose to withhold the vaccine from their children and cases of measles increased as a result.

The subsequent debate about the safety of childhood immunizations roiled for years as the scientific community demanded that Wakefield replicate his results—a demand that Wakefield never met—while launching independent studies of vaccine safety. In 2011, The Lancet retracted the original study, a rare and extreme action on the part of a scientific journal. A few months later, the Institute of Medicine, part of the U.S. Centers for Disease Control and Prevention, published a review of more than 1,000 studies of vaccine safety and found no evidence that MMR or any other childhood immunizations cause autism.

You may think that should be the end of that. You would be wrong.

“Parents remain concerned about the impact of immunizations on a child’s development,” says Dr. Julia Young, a pediatrician with Docs 4 Kidz. Dr. Sandra McKay, a pediatrician on staff at Mercy Children’s Hospital, confirmed that parents also continue to question her about a possible connection between autism and vaccines. “I tell them the evidence, and that is the most compelling argument—data does not lie,” McKay says.

Young echoes the point: “It’s important to understand that vaccines are safer today than ever, as most of the preservatives and thimerosal have been removed. Vaccines can be trusted to protect children and not harm them.”

She also emphasizes the importance of immunity through vaccines as opposed to allowing a child to develop natural immunity by contracting a disease like measles, mumps or whooping cough. “Immunizations are imperative to prevent serious morbidity and mortality from many infections. Over time, many diseases have been successfully eradicated due to herd immunity,” she says. “As people begin refusing vaccines, diseases that were rarely seen due to immunizations, will begin to resurface.” The risks of serious side effects from vaccines are far outweighed by the dangers a child faces if he or she becomes ill with a disease that could be prevented through immunization.

“We know that infants receive passive immunity from their mothers and that by 2 months of life, that immunity wanes and leaves them vulnerable, so that is why the schedule starts at 2 months of age to protect children,” McKay adds. “It is proven that children who have an alternative vaccination schedule are at increased risk (22 times increased risk of measles and six times increased risk of pertussis). I ask my patients’ parents if that is a risk they’re willing to take with their child and inform them that I do not take that risk with my own children—I would never ask them to do something for their child that I would not do for my child.”