Vaccines and the immune system: Some parents and health-care providers are concerned about the increasing number of vaccines being administered to very young children. Parents may be concerned that the infant's immune system is inadequately developed to handle all the vaccines administered over the first two years of life and that receiving so many vaccines could potentially overwhelm the child's immune system. However, studies have not demonstrated that the vaccines weaken the immune system. In fact, the number of antigens to which a child's immune system is exposed through the recommended vaccines is actually lower than the number of antigens individuals encountered 40 or more years ago from naturally occurring infections.14 Some parents and others may believe that the risks associated with a vaccine are greater than the potential of contracting the rarer diseases, such as diphtheria or polio.
Cost factors: Financial and cost factors can influence the availability and promotion of vaccines in private practices. The cost of administering privately purchased vaccines is prohibitive for some providers who are poorly reimbursed for vaccines by insurance carriers and managed health-care plans. The purchase of vaccines is the highest cost incurred by pediatric offices, higher even than personnel costs. Yet some vaccines are reimbursed at a price that does not compensate the health-care office for vaccine administration costs, including those associated with the storage, supply, and personnel necessary to administer vaccines. Economic losses associated with vaccines can result from the previously noted storage problems, expiration of the vaccine before it is administered, and coding or billing errors.
Parental factors
Although NPs and PAs have a voice in the decision to vaccinate a child, the personal and philosophical beliefs of the parents are the most influential in the vaccination decision. Mothers are known to be instrumental in whether children are up to date with vaccines. Addressing maternal concerns and fears regarding vaccines is an important factor in the timeliness of vaccine receipt by preschool-aged children.15 Several factors can influence a parent's decision to vaccinate. Among them are his or her understanding of the risks and benefits of vaccines, perceived threat from the diseases they will prevent, and information that the family has received from the media or other influences. The information regarding vaccines can be very confusing for parents. Many reputable-looking Web sites are actually antivaccine sites. The quality of the information from these sites is suspect.
There has been much publicity in recent years regarding possible links between vaccines and the development of autism or other neurologic disorders. This publicity, along with other actual, unsubstantiated, or disproved vaccine safety concerns, has resulted in parental fears and concerns regarding the safety of vaccines.16 Such fears may cause families to delay immunizations or to decline them altogether.
Adverse outcomes: In 1999, concerns were raised about a causal link between the administration of vaccines containing the preservative thimerosal and the development of autism and/or other neurologic conditions. Since the release of that first report, however, several other researchers have conducted studies to evaluate that relationship. No epidemiologic evidence for a causal association between thimerosal and the development of autism could be identified.17-22
For many families, the fear of adverse reactions or harm from vaccines outweighs concerns of the child's contracting the disease. Some families may still believe that the immunity derived from actually having the disease is superior to the immunity that develops in response to the receipt of a vaccine.23 Contracting some diseases, such as varicella, generally provides lifetime immunity.
WIC: Enrollment in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) was found to be correlated with on-schedule receipt of vaccines by young patients.11,12, 24-27 Children whose mothers participated in the WIC program during pregnancy and continued utilizing WIC services after the birth of their child were more likely to be up to date on vaccines than children from families that did not participate in WIC.
Conclusion
A number of factors affect vaccination rates of children and adults. Many individuals do not know they are missing recommended vaccines that could protect them against preventable diseases. NPs and PAs can improve immunization rates by asking about vaccine status at each and every patient encounter and providing education on the vaccines recommended for the age of the individual. Many people may not be aware of newly available vaccines and will look to you for advice. You may also find yourself explaining and clarifying benefits and risks of vaccines. There is much misinformation about the safety and efficacy of vaccines, and you can be instrumental in assisting patients in receiving needed vaccines and improving the health of your community.
Dr. Stevenson is division director of the Salt Lake Valley Health Department in Salt Lake City and a clinician in an urgent-care setting.
References
1. Centers for Disease Control and Prevention. Recommended adult immunization schedule—United States, 2009. MMWR. 2009;57(53):Q-1-Q-4.
2. U.S. Department of Health and Human Services. Healthy People 2010: Understanding and Improving Health. 2nd ed. Washington, D.C.: U.S. Government Printing Office; November 2000.
3. Luman ET, Barker LF, Shaw KM, et al. Timeliness of childhood vaccinations in the United States: days undervaccinated and number of vaccines delayed. JAMA. 2005;293:1204-1211.
4. Kimmel SR, Burns IT, Wolfe RM, Zimmerman RK. Addressing immunization barriers, benefits, and risks. J Fam Pract. 2007;56(2 Suppl Vaccines):S61-S69.
5. Bartlett DL, Washington ML, Bryant A, et al. Cost savings associated with using immunization information systems for Vaccines for Children administrative tasks. J Public Health Manag Pract. 2007;13:559-566.
6. Hinman AR, Urquhart GA, Strikas RA; National Vaccine Advisory Committee. Immunization information systems: National Vaccine Advisory Committee progress report, 2007. J Public Health Manag Pract. 2007;13:553-558.
7. Smith PJ, Santoli JM, Chu SY, et al. The association between having a medical home and vaccination coverage among children eligible for the Vaccines for Children program. Pediatrics. 2005;116:130-139.
8. Hillenbrand KM. What is going on with vaccines: keeping up with the childhood immunization schedule. J Public Health Manag Pract. 2007;13:544-552.
9. Gore P, Madhavan S, Curry D, et al. Predictors of childhood immunization completion in a rural population. Soc Sci Med. 1999;48:1011-1027.
10. Wood D, Schuster M, Donald-Sherbourne C, et al. Reducing missed opportunities to vaccinate during child health visits. How effective are parent education and case management? Arch Pediatr Adolesc Med. 1998;152: 238-243.
11. Bardenheier BH, Yusuf HR, Rosenthal J, et al. Factors associated with underimmunization at 3 months of age in four medically underserved areas. Public Health Rep. 2004;119:479-485.
12. Brenner RA, Simons-Morton BG, Bhasker B, et al; NIH-D.C. Initiative Immunization Working Group. Prevalence and predictors of immunization among inner-city infants: a birth cohort study. Pediatrics. 2001;108: 661-670.
13. Boulianne N, Deceunick G, Duval B, et al. Why are some children incompletely vaccinated at the age of 2? [French]. Can J Public Health. 2003;94:218-223.
14. Offit PA, Quarles J, Gerber MA, et al. Addressing parents' concerns: do multiple vaccines overwhelm or weaken the infant's immune system? Pediatrics. 2002;109:124-129.
15. Luman ET, McCauley MM, Shefer A, Chu SY. Maternal characteristics associated with vaccination of young children. Pediatrics. 2003;111:1215-1218.
16. Freed GL, Clark SJ, Hibbs BF, Santoli JM. Parental vaccine safety concerns. The experiences of pediatricians and family physicians. Am J Prev Med. 2004;26:11-15.
17. Taylor B, Miller E, Farrington CP, et al. Autism and measles, mumps, and rubella vaccine: no epidemiological evidence for a causal association. Lancet. 1999;353:2026-2029.
18. Confavreux C, Suissa S, Saddier P, et al; Vaccines in Multiple Sclerosis Study Group. Vaccinations and the risk of relapse in multiple sclerosis. N Engl J Med. 2001;344:319-323.
19. Madsen KM, Hviid A, Vestergaard M, et al. A population-based study of measles, mumps, and rubella vaccination and autism. N Engl J Med. 2002;347:1477-1482.
20. Stehr-Green P, Tull P, Stellfeld M, et al. Autism and thimerosal-containing vaccines: lack of consistent evidence for an association. Am J Prev Med. 2003;25:101-106.
21. Hviid A, Stellfeld M, Wohlfahrt J, Melbye M. Association between thimerosal-containing vaccine and autism. JAMA. 2003;290:1763-1766.
22. Parker SK, Schwartz B, Todd J, Pickering LK. Thimerosal-containing vaccines and autism spectrum disorder: a critical review of published original data. Pediatrics. 2004;114:793-804.
23. Chen RT, Hibbs B. Vaccine safety: current and future challenges. Pediatr Ann. 1998;27:445-454.
24. Cortese MM, Diaz PS, Samala U, et al. Underimmunization in Chicago children who dropped out of WIC. Am J Prev Med. 2004;26:29-33.
25.Luman ET, McCauley MM, Shefer A, Chu SY. Maternal characteristics associated with vaccination of young children. Pediatrics. 2003;111(5 Part 2):1215-1218.
26. Morrow AL, Rosenthal J, Lakkis HD, et al. A population-based study of access to immunization among urban Virginia children served by public, private, and military health care systems. Pediatrics. 1998;101:E5.
27. Zúñiga de Nuncio ML, Nader PR, Sawyer MH, et al. A prenatal intervention study to improve timeliness of immunization initiation in Latino infants. J Community Health. 2003;28:151-165.
All electronic documents accessed September 23, 2009.