pediatrics
Vaccine Hesitancy
Use of Multiple, Simultaneous Vaccines
). To minimize the number of injections and visits, clinicians give many vaccines as combination products (eg, diphtheria-tetanus-pertussis, measles-mumps-rubella). However, some parents have become concerned that children's (particularly infants') immune system cannot handle multiple simultaneously presented antigens. This concern has caused some parents to request alternative immunization schedules that delay and sometimes completely exclude certain vaccines. A 2011 nationally representative survey found that 13% of parents use such a schedule ( Use of multiple, simultaneous vaccines references ). The use of alternative schedules is risky and scientifically unfounded. The official schedule is designed to protect children against diseases when they are most susceptible. Delaying vaccination increases the amount of time children are at risk of acquiring these diseases. In addition, although parents may plan to only delay vaccination, the increased number of visits needed for alternative schedules increases the difficulty of adherence and thus the risk that children will not receive a full series of vaccines. Regarding the immunologic challenges, parents should be informed that the amount and number of antigens contained in vaccines is miniscule compared with that encountered in everyday life. Even at birth, an infant's immune system is prepared to respond to the hundreds of antigens the infant is exposed to during delivery and being handled by the (unsterile) mother. Children typically encounter and respond immunologically to dozens and perhaps hundreds of antigens during an ordinary day without difficulty. A typical infection with a single organism stimulates an immune response to multiple antigens of that organism (perhaps 4 to 10 in a typical upper respiratory infection). Furthermore, because current vaccines contain fewer antigens overall (ie, because key antigens have been better identified and purified), children are exposed to fewer vaccine antigens today than they were for most of the 20th century. In summary, alternative vaccine schedules are not evidence-based and put children at increased risk of infectious diseases. More importantly, they offer no advantage. Using data from the VSD, one study compared neurodevelopmental outcomes in a group of children who received all vaccines on time with those who did not ( Use of multiple, simultaneous vaccines references ). The children in the delayed group did not do better on any of the 42 outcomes tested. These results should reassure parents who are concerned that children receive too many vaccines too soon. 1.Dempsey AF, Schaffer S, Singer D, et al: Alternative vaccination schedule preferences among parents of young children.Pediatrics128(5):848-856, 2011. doi:10.1542/peds.2011-0400 2.Smith MJ, Woods CR: On-time vaccine receipt in the first year does not adversely affect neuropsychologic outcomes.Pediatrics125(6)1134-1141, 2010. doi: 10.1542/peds.2009-2489 