Assessing the impact of novelty and conformity on hesitancy towards COVID-19 vaccines using mRNA technology

Plain Language SummaryVaccine hesitancy is a delay in acceptance or refusal of vaccines despite these being available. The hesitancy of the general public towards Covid-19 vaccines remains a challenge for mass vaccination programs. While Covid-19 vaccines using mRNA technology are more effective than vaccines produced using conventional technology, it is unknown how the novelty of the mRNA technology affects vaccine hesitancy among members of the public. Here, we surveyed over 35,000 adults from nine countries and found that the new mRNA vaccine technology leads to greater vaccine hesitancy. However, people are much more willing to accept the vaccine if at least 20% of the population has already received it. These findings show that while the novelty of the mRNA vaccine increases hesitancy, this hesitancy can be reduced by the presence of a small group of early adopters. BackgroundPublic hesitancy towards Covid-19 vaccines remains a major hurdle for mass vaccination programs today. While mRNA vaccines are more efficacious than conventional vaccines, it is unknown how much the novelty of this technology increases hesitancy.MethodsWe quantify this novelty penalty in a large online experiment with 35,173 adults in nine countries. Subjects were randomly selected and assigned to one of two vaccine groups (conventional or mRNA), and one of five hypothetical inoculation rate groups (0%, 20%, 40%, 60%, or 80%). Subjects reported their willingness to accept the Covid-19 vaccine on a five-point Likert scale.ResultsThe novelty of the mRNA vaccine technology reduces the odds of a higher level of vaccine acceptance by 14.2% (odds ratio 0.858; p < 0.001). On the other hand, we find that social conformity reduces vaccine hesitancy. At a 0% inoculation rate, 31.7% report that they are very likely to get a mRNA vaccine while at a 20% inoculation rate, willingness jumps to 49.6%.ConclusionsThe novelty of the mRNA vaccine increases hesitancy, but social conformity reduces it. A small group of early adopters can provide momentum for vaccination. Leong et al. surveyed more than 35,000 participants in nine countries to assess the impact of novelty and conformity on mRNA Covid-19 vaccine hesitancy. They show that the use of mRNA vaccine technology increases the odds of vaccine hesitancy significantly while social conformity reduces it.

Automated summary

The novelty of mRNA vaccine technology increases vaccine hesitancy, but this hesitancy can be reduced by the presence of a small group of early adopters.