Hesitancy towards COVID-19 vaccines threatens to impair the steady progress being made towards achieving widespread immunity, with a sufficient non-vaccinated population to allow SARS-CoV-2 to persist fiercely in some locations. Factors related to safety concerns and distrust of pharmaceutical companies and governments around the world have been amplified by the miss-reporting of facts and outright lies, and the study of how some individuals come to such a decision in the face of overwhelming evidence is an active field.

The health beliefs model is one method of quantifying health behaviors. In a study recently published in the journal Vaccine, this method is utilized to specifically study COVID-19 vaccine hesitancy, bearing in mind that hesitancy is highly variable not only between individuals and location but also in regards to the specific medicine in question.

An online questionnaire was developed that probed the responders perceived severity of disease for themselves or others, the availability of the vaccine and any suspected side-effects, the effectiveness of the vaccine for themselves or others, trust of government, and belief in conspiracy theories.

All respondents were adults living in Australia, the USA, Canada, the UK, or New Zealand. These counties were selected for cultural similarity with disparity of COVID-19 burden. In total, 4,303 usable responses were gathered by the group. These matched the demographics of the country of origin as a whole, except in the case of respondents from New Zealand and the USA having lower median income than the national averages. The average age of Australian respondents being above the national average, 59.5 years compared to 44.5, and above the average of respondents from other nations, at 45.8 years.

Primary pro-vaccine perceptions

All of the data gathered from the questionnaires was weighted and collated into a score, allowing the authors to rank factors and infer the greatest risks to vaccine hesitancy. The first finding was that individuals that perceive COVID-19 as a dangerous disease to themselves are significantly more likely to get vaccinated than those who do not. Those that feel the disease is dangerous to others are more likely still to get vaccinated.

Perceived risk of oneself or others becoming infected had a less significant though still positive impact on vaccine acceptance, again with individuals being more accepting of vaccines when the perceived risk of infection to others, rather than the individual, was high. Perceived effectiveness of the vaccine for oneself or the community also correlated with vaccine acceptance, also showing this pattern of the effect of vaccination on others being a larger factor.

Primary anti-vaccine perceptions

Trust in the government to approve a safe and effective vaccine was the most significant factor relating to vaccine hesitancy. This was followed by the assumption that a large enough number of other individuals will get vaccinated to induce herd immunity and then by those with conspiracy theory beliefs concerning vaccines. Perceived vaccine availability was the least important factor amongst those with no intentions of getting the vaccine.

The impact of most of these factors did not significantly differ proportionately between nations, except for the USA in the case of perceived disease severity, and perceived vaccine efficacy, availability, and safety. Here, these factors had a much greater influence on whether an individual had chosen to be vaccinated.

In contrast, Canada had a weaker relation between perceived disease severity and vaccine effectiveness for an individual, with these factors being less decisive in vaccine intentions. Indeed, these counties had the greatest and least correlation in both directions, with those intending to get vaccinated in the USA rating the virus more deadly and the vaccine most effective, and those not intending to get vaccinated the opposite.

Meanwhile, respondents in Canada expressed the same correlation but much less intensely. The UK has been almost as severely impacted as the USA in terms of proportionate death. These counties were more likely to have these stronger beliefs than counties far less significantly affected, such as Australia or New Zealand.

Other factors and education

Altruistic and collectivist beliefs were positively correlated with the probability of an individual being or planning to get vaccinated. Moreover, older adults were also more likely to be vaccinated.

The unemployed but seeking work had high rates of vaccine intention, while the unemployed but not seeking work were unlikely to get vaccinated, likely due to the call from employers for a vaccinated status.

Education level and previous vaccination against influenza were also strong predictors of vaccine intention, declining with time since the last flu booster. Age, sex, rural or urban status, religiosity, income, household type, political leaning, and several other factors were found to have no significant bearing on vaccine intentions.

The group highlight that, as the most important factor in the decision to vaccinate is trust in government approval of the vaccine, it is critical to ensure transparency in disseminating information relating to efficacy, safety, and other testing processes to the population.

Information is the major mechanism by which vaccine hesitancy can be reduced, and accurate and reliable information that corrects circulating conspiracy theories could improve vaccine intentions.

Direct methods of information dissemination, such as communication from a health professional, are often the most effective. However, given the wide-scale problem of vaccine hesitancy, this approach may not reach a sufficient number.

Multi-media methods may be employed, though, in a large proportion of cases, confirmation bias and other fallacies limit the effectiveness of such measures against those with anti-vaccination beliefs. Emphasis on protecting the wider community and vulnerable family members seems to be one of the strongest factors in vaccine acceptance. Focusing on this message along with highlighting further losses likely to be incurred if vaccine hesitancy persists may be the best strategy going forward.

Written by

Michael Greenwood

Michael graduated from Manchester Metropolitan University with a B.Sc. in Chemistry in 2014, where he majored in organic, inorganic, physical and analytical chemistry. He is currently completing a Ph.D. on the design and production of gold nanoparticles able to act as multimodal anticancer agents, being both drug delivery platforms and radiation dose enhancers.