Vaccine hesitancy: the 5C model and the consultation

A father arrives at his daughter's one-year checkup with a printed list of questions. He read that there are too many vaccines for a small body, heard from a neighbor that her son had a high fever after the MMR vaccine, and wants to know if everything can be postponed until after the summer. The pediatrician has twelve minutes. The way he opens the conversation in the next thirty seconds weighs more on the outcome than the amount of data he manages to present.

Vaccine hesitancy is the delay in accepting or the refusal of vaccines despite their availability, in the definition used by the World Health Organization, which placed it among the most urgent threats to global health (Kaushik, 2025). It is rarely a fixed position. In most families, it is a doubt that can grow or shrink depending on the experience with the health service.

This text presents the 5C model as a map for understanding where the doubt comes from, compares recommendation formats studied in real consultations, and shows what the evidence says about motivational interviewing and correcting misinformation.

Key points

• About 21 in every 100 parents of young children report hesitancy about routine vaccines, with variation across regions of the world (Abenova, 2023).
• The 5C model describes five psychological antecedents of vaccination: confidence, complacency, constraints, calculation and collective responsibility (Betsch, 2018).
• Announcing the vaccine as the expected step of the visit was associated with better coverage than opening the decision as a question (Opel, 2018).
• Training professionals in announcement-based recommendation increased HPV vaccination in adolescents; training centered on conversation had no effect (Malo, 2018).
• Motivational interviewing reduced hesitancy in postpartum mothers in a randomized trial, with an effect that persisted for months (Verger, 2023; Ramalli, 2026).
• Correcting myths can work, but the format matters and the evidence on the backfire effect is conflicting (Pluviano, 2017; Ecker, 2023).

Summary

• What vaccine hesitancy is and how common it is
• From the 3C model to the 5C: a map of the reasons
• Why the doubt appears: biases and misinformation
• Presumptive or participatory recommendation
• Motivational interviewing in the vaccination visit
• Correcting misinformation without reinforcing it
• Parent profiles and how to adapt the conversation
• How NEXO helps train this reasoning
• Frequently asked questions
• Take-home messages

What vaccine hesitancy is and how common it is

Vaccine hesitancy occupies the space between unquestioning acceptance and total refusal. A systematic review of 34 studies described parental hesitancy as a continuum: there are those who accept everything with doubts, those who delay some vaccines, those who choose only part of the schedule and, at a small end, those who refuse all of them (Obohwemu, 2022). Treating these groups as a single block leads to conversations that serve no one.

A meta-analysis of 23 cross-sectional studies, with 29,131 parents of children from zero to six years old in more than 30 countries, estimated that about 21 in every 100 parents are hesitant about routine vaccines. The proportion was lower in the Americas, close to 13 in every 100, and higher in the Eastern Mediterranean, close to 28 in every 100 (Abenova, 2023). The measurement instruments varied between studies, which calls for caution in direct comparisons between countries.

Hesitancy also appears in families whose children are up to date with the schedule. A review on language in the consultation notes that between 15 and 35 in every 100 parents of well-vaccinated children report some degree of hesitancy (Jacobson, 2020). This means that the child vaccinated today may have a parent who delays the next vaccine if the experience of this visit is bad.

Why the topic matters for those who provide care

Coverage drops open space for outbreaks of diseases that seemed controlled. Measles is the first sign, because it is highly transmissible, and diphtheria returns where routine vaccination has failed for years. The posts about measles when vaccination stops and about diphtheria outbreaks when vaccination falls show what happens at the other end of this chain.

For the clinician, hesitancy rarely arrives under that name. It shows up as a request to "leave it for next time", a question about ingredients, a story of a reaction in a relative, or an uncomfortable silence when it is time to sign. Recognizing these signs is the first step, and the 5C model helps organize them.

From the 3C model to the 5C: a map of reasons

The first hesitancy models grouped the reasons into three groups: confidence in vaccines and in the system, complacency about the risk of the disease, and convenience of access. This 3C model, proposed by a SAGE working group at WHO, was later expanded to four dimensions, with the inclusion of calculation, that is, the active search for information to weigh risks and benefits (Betsch, 2018).

Betsch and colleagues proposed the 5C model, which adds collective responsibility and renames convenience as constraints. In three studies, with 1,445, 1,003 and 350 participants, the group developed a long scale of 15 items and a short one of 5 items, which explained more variation in vaccination behavior than measuring confidence alone (Betsch, 2018).

The five dimensions

Confidence is the belief in the efficacy and safety of vaccines, in the system that offers them and in the motivations of those who decide policies. Complacency happens when the risk of the disease seems low, to the point that vaccination does not seem necessary. Constraints are structural and psychological barriers: opening hours, distance, indirect cost, difficulty understanding the schedule (Betsch, 2018).

Calculation describes the person who seeks a lot of information to decide. Those who calculate a lot tend to find more content against vaccines, simply because they search more and in more places. Collective responsibility is the willingness to get vaccinated to protect others, including those who cannot receive the vaccine (Betsch, 2018).

Why the map helps in the consultation

Each dimension calls for a different response. A parent with low confidence needs a professional they can trust, more than a chart. A complacent parent needs to understand that the disease still circulates. A mother with constraints needs a possible appointment time, not a lecture. Obohwemu's review grouped the barriers found in the studies by exactly these dimensions, which shows that the model applies well to practice (Obohwemu, 2022).

Listening before responding is what allows you to identify the dimension at play. The clues the patient offers during the consultation usually reveal whether the doubt is about safety, about necessity or about logistics.

Why the doubt appears: biases and misinformation

The decision about vaccinating involves judging small and distant risks, and that is the ground where human reasoning uses shortcuts the most. The same mental shortcuts that appear in clinical reasoning also guide parents and patients.

Omission bias and status quo bias

Omission bias is the tendency to judge harm caused by an action as worse than equal or greater harm caused by not acting. For a parent, a reaction after the vaccine weighs as their own fault; a disease the child catches for not being vaccinated seems like an accident. Status quo bias reinforces this effect by favoring the option that keeps everything as it is. Opel and colleagues cite these two biases to explain why asking "what do you want to do?" can push the decision toward postponement (Opel, 2018).

Availability also counts. The story of the neighbor whose child had a fever is concrete and close; the children who did not get measles thanks to the vaccine are invisible. The rarer the disease becomes, the more the mental balance tips toward the perceived risk of the vaccine.

Misinformation and the weight of searching

Misinformation spreads quickly and relies on personal stories, images and emotional language. The effect is greater among people with a high calculation profile, who actively search and end up exposed to more misleading content (Betsch, 2018). The review on the United States scenario describes social media and the loss of trust in institutions as important drivers of recent hesitancy (Kaushik, 2025).

A meta-ethnography of 12 studies heard professionals who care for hesitant parents. The accounts describe frustration, a feeling of talking to "a stone that refuses to be sculpted" and the risk of the relationship wearing down. The authors conclude that the therapeutic alliance is the central tool, and that rushing to convince tends to push the family away (Fernández-Basanta, 2021).

Presumptive or participatory recommendation

The format of the first sentence about vaccines has been studied with recordings of real consultations. In the presumptive format, the professional announces the vaccine as a natural part of the visit: "today she will receive her one-year vaccines". In the participatory format, he opens the decision as a question: "what do you think about today's vaccines?"

What the Seattle study showed

Opel and colleagues followed 73 parent-child pairs in Seattle, with recorded consultations and vaccination records over time. About 65 out of every 100 parents received the presumptive format at least once and 42 out of every 100 the participatory format. The participatory format was associated with 10.1 more days without up-to-date vaccination for every 100 days of follow-up, which added up to about 98 more days for the set of six vaccines evaluated (Opel, 2018).

The study is observational and small. More hesitant parents may have received the participatory format precisely because the professional noticed the doubt. Even with this limitation, the result adds to other data that point in the same direction.

The trial with announcement training

Malo and colleagues analyzed a trial in 20 clinics in North Carolina, with 11,578 adolescents aged 11 and 12 and 83 professionals. The clinics received training in announcement recommendation, training in conversation recommendation or no training. The announcement training increased HPV vaccination; the conversation training did not change coverage (Malo, 2018).

The theoretical analysis suggests why the announcement worked. The average discussion time fell from 3.8 to 3.2 minutes, the professionals felt more confident and the vaccine came to be presented as the norm, alongside the other vaccines for that age (Malo, 2018). The gain came from the form of the recommendation, not from more conversation time.

Strength of the recommendation

The professional's recommendation is among the most consistent factors for vaccine acceptance. Strong and clear recommendations beat weak or ambiguous ones, and purely educational interventions sometimes backfire by reinforcing doubt (Jacobson, 2020). A sentence like "if it were my child, I would vaccinate today" carries the professional's confidence without needing statistics.

Presumptive is not imposing

Announcing the vaccine is different from ending the conversation. The announcement works as a starting point for those who accept without major doubts, which is the majority. If the parent raises a concern, the next step is to listen, acknowledge the doubt and respond, without abandoning the recommendation. Leask and colleagues describe this balance as a clear recommendation accompanied by openness to questions and valid consent (Leask, 2012).

This point creates a tension with shared decision-making, which is the standard for choices in which there is more than one reasonable option. In the routine schedule, the benefits clearly outweigh the harms, and the professional's task is to communicate a recommendation, not to present a neutral menu. In situations of real balance, such as some optional vaccines in adults, the three-conversation shared decision-making model becomes the reference again.

Motivational interviewing in the vaccination consultation

Motivational interviewing is a conversation style that helps the person explore their own ambivalence and find reasons to change. It uses open questions, affirmations, reflections and summaries, the OARS skills, and avoids the reflex to correct, which usually generates resistance.

The trial with midwives in France

Verger and colleagues randomized 733 mothers in maternity units in southeastern France. The intervention group talked with midwives trained in motivational interviewing; the control group received a leaflet. Hesitancy fell 5.8 points more in the intervention group, on a scale from 0 to 100, and the intention to vaccinate rose 0.6 point more, on a scale from 0 to 10. The effect was larger among mothers with high initial hesitancy and with less schooling (Verger, 2023).

The follow-up of the same trial, about seven months later, showed that the effect held and even increased: a drop of 10.1 points in hesitancy and a rise of 0.8 point in intention. The benefit was consistent among mothers with different financial situations (Ramalli, 2026).

What the reviews say

The overall picture is more modest. A systematic review of 118 studies compared educational interventions, of which there were 108, with motivational interventions, of which there were 10. Compared with usual care, education was associated with a small increase in vaccination (relative risk of 1.10), and motivational interviewing with an increase of 1.07 without statistical significance. The quality of the studies was low, and the authors call for better trials before firm conclusions (Labbé, 2025).

The two findings coexist. Motivational interviewing seems to help more those who are in fact ambivalent, like the mothers with high hesitancy in the French trial. For the majority who accept, a clear recommendation is enough. The post on why explanation alone fails details this mechanism, and the one on what the evidence shows sums up the limits of the method.

What it looks like in practice

After the announcement, if the father hesitates, an open question helps: "what worries you about this vaccine?". Reflection shows that the concern was heard: "you want to be sure it won't harm her". Next, permission is asked to offer information, and the answer focuses on the specific doubt. At the end, a summary gives back to the father what he said and the professional's recommendation.

The review by Kaushik and colleagues describes this path in pediatrics and suggests that motivational interviewing be used as a complement to the strong recommendation, and not as a substitute (Kaushik, 2025). Leask and colleagues also recommend a guiding style, which sits between the directive and the purely following, and encourage the professional to evoke the father's own motivations to protect his child (Leask, 2012).

Correcting misinformation without reinforcing it

When a father brings up a myth, the natural reaction is to refute it at once. The evidence on the best format for this correction has changed in recent years and still has open points.

The fear of the backfire effect

Pluviano and colleagues, at the University of Edinburgh, tested three pro-vaccine strategies: a myths-and-facts leaflet, charts with data, and images that appealed to fear of the disease. All three failed to reduce wrong beliefs, and some worsened the intention to vaccinate over time. The authors suggested that repeating the myth, even to deny it, could make it more familiar and more credible (Pluviano, 2017).

The replication that did not confirm it

Ecker and colleagues tried to replicate this effect, added a condition with only myths labeled as false, and measured beliefs right after the correction and seven days later. The myths-and-facts format reduced wrong beliefs, and the authors found no backfire effect from familiarity or from fear at either time point (Ecker, 2023). The practical conclusion is that correcting is better than staying silent, as long as the correction is clear.

The format that usually works

A few simple rules help. Start with the correct fact, not with the myth. Mention the myth once, making it explicit that it is false. Explain why it is false, with a mechanism that fills the space left. Close by repeating the fact. Throughout the process, check whether the family understood, with teach-back, which asks the person to explain in their own words what they heard.

Appeals to fear call for care. Strong images of sick children can drive away anxious parents, as Pluviano's study suggests (Pluviano, 2017). A concrete and calm description of what the disease causes, preferably linked to the professional's own experience, tends to be more useful.

Parent profiles and how to adapt the conversation

Leask and colleagues proposed a framework for professionals with five approximate parent profiles. Those who accept without questioning would be 30 to 40 out of every 100; those who accept with caution, 25 to 35; the hesitant, 20 to 30; those who delay or choose some of the vaccines, 2 to 27, depending on the country; and those who refuse all of them, fewer than 2 out of every 100 (Leask, 2012). The proportions are estimates from different studies, but the message is clear: total refusal is rare, and most of the conversation happens with parents who are still deciding.

A conversation for each profile

For those who accept without questioning, the announcement is enough, along with a brief explanation of what to expect afterwards. For those who accept with caution, it is worth setting aside a minute for questions and acknowledging that having doubts is normal. For the hesitant, the conversation benefits from a guiding style, with open questions and information directed at the real concern (Leask, 2012).

For those who delay or choose, it helps to prioritize the most urgent vaccines for the age and to agree on a concrete date for the next ones. For those who refuse, the goal is to keep the door open: record the conversation, make it clear that the professional remains available and bring the topic up again at another visit, without breaking the bond. The safety net also applies here, with specific guidance on the signs of illness that require a quick return in an unvaccinated child.

The 5C table in the consultation

The table below gathers signs that often appear in the conversation and responses consistent with the evidence. It is a support for organizing the reasoning, not a rigid script.

5C dimension	Sign in the consultation	How to respond
Confidence	"I don't know if these vaccines are safe" or distrust of those who make them	Acknowledge the concern, explain how safety is monitored and offer your own recommendation clearly
Complacency	"Nobody gets that disease anymore"	Tell them that the disease still circulates and what happens when coverage falls, with concrete examples
Constraints	Repeated missed appointments, difficulty with the schedule, confusion about the calendar	Make use of the current visit, simplify the plan and agree on the next date before the family leaves
Calculation	A list of questions, extensive reading on the internet, requests for studies	Value the search, answer point by point and point to reliable sources, without dismissing the effort
Collective responsibility	"My child is healthy, I don't need it"	Remind them who depends on collective protection, such as very young babies and immunosuppressed people

The relationship comes before the argument

Fernández-Basanta's meta-ethnography reinforces that the bond is what sustains any technique (Fernández-Basanta, 2021). A parent who feels judged tends to look for another service or to avoid consultations, which reduces the chances of vaccinating in the future. Thinking of the relationship as a protection tool helps the professional see each conversation as part of a long relationship.

Professionals themselves also have biases. Excessive confidence in predicting who will accept or refuse can lead to choosing the wrong format right from the start. Calibrating confidence applies to this reading as much as to the diagnosis.

Adults and other contexts

Much of the evidence comes from parents of children, but the 5C model was also developed and tested with adults deciding about their own vaccination (Betsch, 2018). In an adult consultation, the same signs appear with different content: the complacent older adult who thinks flu is trivial, the worker with schedule constraints, the pregnant woman who calculates every risk. The logic of the response is the same.

The French trial shows that the postpartum period is a moment of opportunity, because the mother is in frequent contact with the service and actively thinking about the baby's health (Verger, 2023). Moments of transition, such as the first well-child visit or starting school, offer similar windows.

How NEXO helps train this reasoning

In NEXO, the case of the day is fictional, with a real clinical presentation and up to six progressive clues, and you propose the diagnosis by searching for the ICD-10 code. Many cases of vaccine-preventable diseases begin with an incomplete vaccination history, and recognizing this detail is part of the reasoning.

The limits on using the game are described on the Economy page of NEXO. If you research the teaching of clinical reasoning, the page for Researcher explains how to get in touch. Professionals who write or review cases find information on Curator and on Creators, and institutions can learn about the proposal on the partnerships page. To practice finding the code, see how the ICD-10 code is built.

Frequently asked questions

What is vaccine hesitancy?

It is the delay in accepting or the refusal of vaccines even though they are available. It ranges from minor doubts to total refusal, and most hesitant parents end up vaccinating when the conversation is well conducted (Kaushik, 2025; Obohwemu, 2022).

What are the 5C of vaccine hesitancy?

Confidence, complacency, constraints, calculation and collective responsibility. Each dimension describes a different reason for the doubt and calls for a different response (Betsch, 2018).

What is the best way to recommend a vaccine?

The available studies favor the presumptive format, which announces the vaccine as an expected part of the visit, followed by openness to questions if there is doubt (Opel, 2018; Malo, 2018).

Does motivational interviewing work for vaccines?

A randomized trial with postpartum mothers showed a reduction in hesitancy that persisted for months. Reviews, however, find a small effect and low-quality studies, so the method seems more useful for those who are genuinely ambivalent (Ramalli, 2026; Labbé, 2025).

Can debunking a myth make things worse?

A 2017 study suggested this risk, but a larger 2023 replication found a reduction in false beliefs and no backfire effect. Correction works best when it begins and ends with the correct fact (Pluviano, 2017; Ecker, 2023).

What should be done when the family refuses all vaccines?

Maintain the relationship, document the conversation, advise on warning signs and bring the topic up again at the next visits. Total refusal is rare, and a preserved relationship increases the chance of future change (Leask, 2012; Fernández-Basanta, 2021).

How many parents are hesitant worldwide?

A meta-analysis estimated about 21 out of every 100 parents of young children, with variation between regions (Abenova, 2023).

Take-home messages

• Vaccine hesitancy is a continuum, and most hesitant parents are still deciding.
• The 5C model organizes the reasons for doubt into confidence, complacency, constraints, calculation and collective responsibility.
• Announcing the vaccine as the expected step of the visit is associated with better coverage than opening the decision as a question.
• A strong, clear recommendation from the professional is one of the most consistent factors for acceptance.
• Motivational interviewing helps those who are ambivalent and works best as a complement to the recommendation.
• Correcting myths is worthwhile when the correction begins and ends with the correct fact.
• A preserved relationship is what keeps the door open for the next vaccine.

Play the case of the day on NEXO.

References

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9. Verger P, Cogordan C, Fressard L, Gosselin V, et al. A postpartum intervention for vaccination promotion by midwives using motivational interviews reduces mothers' vaccine hesitancy, south-eastern France, 2021 to 2022: a randomised controlled trial. Euro Surveill. 2023. PMID 37733238. DOI 10.2807/1560-7917.ES.2023.28.38.2200819.
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13. Fernández-Basanta S, Lagoa-Millarengo M, Movilla-Fernández M, et al. Encountering Parents Who Are Hesitant or Reluctant to Vaccinate Their Children: A Meta-Ethnography. Int J Environ Res Public Health. 2021. PMID 34300041. DOI 10.3390/ijerph18147584.
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