THE BIGGEST WORRY A NURSE giving vaccinations used to face was a crying child or an adult who faints at the sight of the needle. But ensuring community protection from infectious diseases has become more complex in recent years. Patients often are unaware of required vaccinations. Parents may resist childhood shots due to fears of autism. State and federal immunization schedules have expanded. And a surprising number of healthcare workers neglect or refuse influenza shots.

Despite evidence that vaccination improves overall population health, nurses still may need to debate its merits with patients or coworkers. By learning about some of the current controversies surrounding the practice, and preparing a strategy to educate patients, you can help them make the best choices for themselves, their children, and community health.

CONTINUING VACCINATION CHALLENGES Vaccination coverage in America has been historically high as a result of school requirements, caregiver intervention with vulnerable populations, and seasonal influenza-shot drives, but it still falls short—sometimes lethally. In February and March 2009, two schoolchildren died from the flu on Long Island, NY.^1,2 Four young Colorado children have succumbed to flu since January 2009.³ Five surprise Minneso- ta cases of Haemophilus influenzae type B (Hib) in 2008 represented the biggest outbreak since 1992.⁴ And although endemic measles transmission was considered halted in 2000, new cases surged during the next few years.⁵

Vaccine shortages. Manufacturing recalls can open serious gaps in vaccine administration, due to the small number of approved producers for the US healthcare system. As a secondary effect, media reports of vaccine recalls can foster patients' distrust of immunization.

Immigration, travel, & infection. The Centers for Disease Control and Prevention (CDC) reported that 76% of measles cases in the first half of 2008 were traceable to imported sources.⁵ US travelers abroad may not know vaccination requirements for their destinations. And new immigrants may be unaware of American vaccination schedules.

Awareness of available vaccines. Adult patients may not know which boosters and preventive vaccines are advised for their age group. The CDC has noted, for example, that shingles and human papillomavirus (HPV) vaccines, along with the pertussis booster, have not been adopted as readily as those for more well-known diseases such as flu.⁶ And state health departments may revise childhood-vaccination requirements, as New Jersey recently did for the flu vaccine.

Inability to pay. Indigent patients presenting in emergency departments or clinics may have missed key vaccinations because they lack health insurance. They may be able to find low-cost or free vaccinations at public health departments. (The federal Vaccines for Children Program provides free vaccinations through state health bureaus via Medicaid.)

PATIENT RELUCTANCE OR REFUSAL Common reasons why patients refuse vaccines for themselves or their children include doubts over vaccine safety, belief that past shots and subsequent illness are connected, religious or moral opposition, the expectation that they or their children will never encounter diseases (ironically a product of vaccination's historical effectiveness in suppressing once-rampant pathogens), and lack of trust in governmental or scientific authorities.⁷

Vaccination side effects for most patients usually are limited to a fever or a reddened, swollen, or sore injection site. But serious reactions can occur with any medication. To minimize injury, the CDC's Vaccine Information Statements list contraindications and precautions for each vaccine, along with known side effects, action plans if they occur, and contact information for reporting them to the official registry. The CDC also provides a list of vaccine misconceptions to help caregivers address common patient concerns.⁸ Overall, severe problems are very rare, in some cases statistically incapable of being traced uniquely to the vaccine.⁹

When reports of vaccine recalls or injury litigation reach patients, they may worry about safety, or even bring news printouts to vaccine appointments. It's wise to respect their concerns, but guide patients to evidence-based data to relieve misconceptions or supplement news stories. For instance, parents may be concerned about their child's scheduled polio vaccination because they've heard about a legal settlement against the manufacturer of oral, live-polio vaccine Orimune, blamed for giving a parent polio in 1979 via a diaper change of a just- immunized infant. These stories failed to specify that since 2000 the CDC has recommended injected, inactivated polio vaccine, to avoid the rare development of polio that occurred in some live-vaccine recipients during 20th-century eradication efforts.^10,11

AUTISM CONCERNS Parents may be reluctant to vaccinate children due to fears of autism-spectrum disorders (ASDs) from vaccine preservatives, particularly thimerosal (which contains mercury); the age and frequency at which children receive shots; or use of certain combined vaccines, particularly the measles-mumps- rubella (MMR) shot.

Thimerosal. In a 1999 Food and Drug Administration review of pediatric vaccines' mercury levels, no evidence was found of thimerosal being harmful to children. The Public Health Service nonetheless advised vaccine makers "to reduce or eliminate thimerosal in vaccines as soon as possible" as a precaution until more was known about the toxicity of ethylmercury (thimerosal's metabolite) versus methylmercury (the metabolite of ingested elemental mercury).¹² Vaccines free of thimerosal, or including only microgram-quantity traces, were approved for pediatric use over the subsequent decade. The outcome of an Institute of Medicine (IOM) follow-up study led the IOM to state that there is no causal link between autism and thimerosal in vaccines or ethylmercury. The CDC supports the conclusion.¹³

MMR. The hypothetical connection between MMR use and ASDs originated with a 1998 study of ASD in a group of 12 British children, eight of whom manifested autism after they suffered gastrointestinal disorders that the researchers ascribed to MMR shots. Public outcry and opposition to vaccination began after The Daily Telegraph in London reported the results as an obvious vaccine-autism link. MMR use dropped in several countries, with subsequent measles and mumps outbreaks.¹⁴ The study's results have never been replicated, and nearly all of its authors have retracted its conclusions.^15,16

Both vaccine-ASD relations were addressed in a February 2009 US Court of Federal Claims decision. The court ruled against three families who had appealed to the National Vaccine Injury Compensation Program over a perceived link between their children's ASD and use of thimerosal preservative or the combined MMR shot.¹⁷

For parents who worry about vaccines in general, or thimerosal in particular, here are some starting points for a discussion:

• Guide parents to authoritative information on ASDs, MMR vaccine, and vaccine safety. (See "Quick Shots," page 38.) Remind them that no definitive cause of autism has yet been determined.
• Explain to parents that although ASD diagnoses are made in the same phase of a child's life as they receive frequent vaccinations, this doesn't represent a definite causal link.
• Share CDC information on removal or reduction of childhood-vaccine thimerosal. Point out that many vaccines have never contained it, and that diagnoses of ASDs have accelerated even after remaining thimerosal was eliminated or minimized.¹⁵
• Contrast the low frequency of side effects with the hazards children face if they go unvaccinated.¹⁷ Remind parents that vaccination gaps can allow diseases under control in America to reenter via travel from countries with lower rates of vaccination coverage. In the 2008 measles outbreak, for instance, more than half of victims were deliberately unvaccinated.⁵