Current controversies in the USA regarding vaccine safety.

As a result of the vaccines discovered in the 20th Century, parents and many healthcare providers of the 21st Century have limited or no experience with the devastating effects of diseases such as polio, smallpox or measles. Fear of disease has shifted to concerns regarding vaccine safety. Scientific evidence has refuted many of the misconceptions regarding vaccine safety; however, parental refusal of vaccines is increasing. Here we review six of the most prevalent controversies surrounding vaccine safety: the proposed causal relationship between receipt of the measles-mumps-rubella vaccine and autism; thimerosal as a potential trigger for autism; religious objection based on some vaccine viruses being grown in cell lines from aborted fetal tissues; parental worries that use of the human papillomavirus vaccine may lead to youth promiscuity; fears regarding the purported association between pertussis vaccination and adverse neurological outcomes; and concerns regarding too many vaccines overloading or weakening the infant immune system. Healthcare providers are ideally positioned to correct these misconceptions, but they must recognize and acknowledge parents' concerns, educate themselves on the latest scientific research that addresses these, and dedicate sufficient time to discuss vaccine safety with worried parents.