Resurgence of Measles in Europe: A Systematic Review on Parental Attitudes and Beliefs of Measles Vaccine

"The complex, multidimensional decision-making process behind vaccination underpins the need for multilevel policy intervention."

Beginning in 2018, Europe experienced a resurgence of measles, despite availability of and access to a safe, effective, and affordable vaccine. The main driver for the outbreak is suboptimal vaccine coverage, which is influenced by decision-making that is context-specific and reliant on knowledge and information, attitudes and values, and experiences and emotions. The objectives of this study are to: (i) synthesise and assess evidence on parental attitudes and beliefs toward measles, mumps, and rubella (MMR) uptake in Europe; and (ii) develop strategies and policy recommendations to improve MMR vaccine uptake and identify areas for further research.

As the researchers explain, MMR-related fears were triggered by Andrew Wakefield's (1998) study, published in The Lancet, suggesting a causative link between MMR and autism. Although the study has since been retracted, his findings fueled publicity amongst anti-vaccination groups and negative press worldwide, led to a decline in measles vaccination coverage in the United Kingdom (UK), and arguably contributed to the vaccine hesitancy that is still present (and increasing) today.

Twenty studies met inclusion criteria for a systematic review that was conducted of relevant primary studies conducted in Europe that were published between 2011 and April 2019. (See Table 2 in the paper for a summary of study characteristics.) Data were extracted using an inductive grounded theory approach. In presenting the results, the researchers use the terms 'acceptors' and 'rejectors' in reference to parents' complete acceptance or refusal of MMR, whereas "vaccine-hesitant" parents represent attitudes between the two.

The 6 key themes identified from a review of the 20 studies were:

1. Measles vaccine factors (e.g., experience (self/peers) of vaccine side effects);
2. Measles factors (e.g., perceived low susceptibility to measles);
3. Trust factors (e.g., bad experience/relationship/communication with healthcare workers;
4. Social factors (e.g., perceived pressure and judgement from peers and family about responsible parenting, morals, and intellect);
5. Practical factors (e.g., lack of timely vaccination invitation); and
6. Knowledge factors (e.g., misinformation online/media).

Using the 3Cs model of vaccine hesitancy, these 6 themes can be grouped into 3 main categories: confidence, complacency, and convenience. "Convenience is a particularly important category as not only does convenience determine enabling factors for vaccination but it also establishes barriers to vaccination regardless of parental desire to vaccinate. Complacency is most important when considering tailoring immunization strategies most effectively. However, the most important and most common theme that arose was fear about confidence of measles vaccination."

Certain communities, such as Gypsy, Roma, and Traveler (GRT) populations, presented unique barriers such as accessibility, with geographic and social isolation of those communities excluding mothers from health promotion interventions, magnifying the lack of vaccination knowledge, and increasing reliance on informal sources of information.

Factors supportive of MMR uptake included a sense of responsibility toward child and community health, peer judgement, trust in experts and vaccine, and recognition of measles severity. For example, Swedish parents with greater trust were found to be more likely to vaccinate on time, dismiss MMR rumours, and ask more questions. And a questionnaire showed that more acceptors and vaccine-hesitant parents in Italy considered their paediatrician to be competent and to have spent enough time discussing MMR uptake, compared with rejectors. ("However, one study in Germany showed that too much time discussing MMR discouraged uptake, emphasizing the balance required to make this effective.")

Reflecting on the systematic review, the researchers propose a multi-interventional, evidence-based approach to improve the 3Cs of measles vaccination uptake. Suggestions offered include:

• In crafting their communication around vaccination, healthcare professionals should seek to better understand individual contextual attitudes and barriers to MMR uptake. They should "aim to understand individual reasons for decisions, and tailor communication to target their unique experiences, beliefs, and attitudes, making information more relevant, trustworthy, and impactful."
• Healthcare environments should strive to be nondiscriminatory and fully inclusive of all communities and minorities.
• Adequate surveillance and monitoring fosters efforts to identify under-vaccinated populations, send reminders for vaccination, and monitor progress in immunisation coverage.