Vaccine hesitancy, vaccine refusal and the anti-vaccine movement: influence, impact and implications

Abstract

Despite being recognized as one of the most successful public health measures, vaccination is perceived as unsafe and unnecessary by a growing number of parents. Anti-vaccination movements have been implicated in lowered vaccine acceptance rates and in the increase in vaccine-preventable disease outbreaks and epidemics. In this review, we will look at determinants of parental decision-making about vaccination and provide an overview of the history of anti-vaccination movements and its clinical impact.

Keywords:

• anti-vaccination
• parents
• vaccination decisions
• vaccine hesitancy
• vaccine refusal

Acknowledgements

The authors would like to thank M Duchesne, Laval University, and D Gagnon, Institut national de santé publique du Québec, for their help in drafting this manuscript.

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• The high rate of childhood vaccination coverage in most countries indicates that vaccination remains a widely accepted public health measure. However, these national estimates may hide clusters of undervaccinated individuals.

• Many recent outbreaks of vaccine-preventable diseases have been linked to undervaccinated or non-vaccinated communities.

• Many studies have shown that parental decisions to use or avoid immunization for their children are complex and multi-dimensional, including contextual determinants, determinants related to the vaccination services and individual determinants, such as parents’ knowledge, attitudes and beliefs or sociodemographic characteristics.

• While minority of parents hold strong anti-vaccination sentiment, the proportion categorized as vaccine-hesitant may be increasing; even parents who vaccinate their child can have important doubts and fears regarding immunization.

• Anti-vaccination is as old as vaccination itself and is not likely to disappear. With the Internet, the anti-vaccination movements are more powerful than ever and have the potential to reach and influence many parents.

• Despite significant efforts, few, if any, public health strategies have effectively and long-lastingly succeeded in countering anti-vaccination movements. It is time to move beyond the ‘knowledge deficit model’ to develop innovative responses to address anti-vaccination sentiment.

• A first and important step to develop effective strategies is to have a good understanding of both the causes and of the contexts leading to vaccine hesitancy and refusal.

• Interventions must be tailored to address the specific concerns in a given context, time and vaccine.

Notes

¹Noting the common observation that milkmaids were generally immune to smallpox, Jenner postulated that the pus in the blisters that milkmaids received from cowpox (a disease similar to smallpox, but much less virulent) protected them from smallpox. On 14 May 1796, Jenner tested his hypothesis by inoculating James Phipps, an 8-year-old boy who was the son of Jenner’s gardener. He scraped pus from cowpox blisters on the hands of Sarah Nelmes, a milkmaid who had caught cowpox from a cow called Blossom. Jenner inoculated Phipps in both arms that day, subsequently producing in Phipps a fever and some uneasiness, but no full-blown infection. Later, he injected Phipps with variolous material, the routine method of immunization at that time. No disease followed. The boy was later challenged with variolous material and again showed no sign of infection [52].

²Henning Jacobson’s arguments that the compulsory inoculation violated his right to care for his own body and health was rejected by the Massachusetts courts, including the Supreme Judicial Court. Jacobson was supported by the Massachusetts Anti-Compulsory Vaccination Association.

³The authors’ conclusions were that: ‘Prior receipt of 2008–09 TIV was associated with increased risk of medically attended pH1N1 illness during the spring–summer 2009 in Canada. The occurrence of bias (selection, information) or confounding cannot be ruled out. Further experimental and epidemiological assessment is warranted. Possible biological mechanisms and immunoepidemiologic implications are considered’ [94]. In an anti-vaccination website, the study was used in support allegations that vaccination against a disease will increase the risk to contract other diseases: ‘Why Getting a Vaccine for One Disease Could Make You More Likely to Catch Another. Remember that ALL vaccines are immune suppressing, meaning they lower your immune functions. The chemicals and adjuvants in the vaccines depress your immune system; the viruses present depress immune function, and the foreign DNA/RNA from animal tissues depresses immunity – that is the trade-off you are risking’ [95].