Researchers identify factors influencing vaccine reluctance in the US

A team of scientists from Washington University in St. Louis, USA recently conducted a survey to analyze factors responsible for reluctance to vaccinate against coronavirus disease 2019 (COVID-19) among US citizens. The results of the study show that public vaccination readiness can likely be improved by allowing vaccine brands and locations to be selected. In contrast, vaccine mandates can further increase public aversion to vaccination. The study is currently available on the medRxiv * preprint server.


The recent outbreak of the severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2), the causative agent of Coronavirus Disease 2019 (COVID-19), has put a significant strain on the global health system due to the high viral infectivity and the severity of the disease. Although numerous advances have been made in vaccination science, mass vaccination programs in many countries are facing serious challenges due to public skepticism about the COVID-19 vaccine.

As COVID-19 vaccines have developed rapidly, there has been increasing public hesitation about the safety and effectiveness of vaccines. A significant segment of the general population is not convinced of the true severity of COVID-19.

In the current study, the scientists examined strategies to increase vaccination rates in the general population in the United States. They specifically aimed to identify factors linked to public reluctance to get COVID-19 vaccination.

Study participants

The study was conducted on 2,895 US citizens (age group: 33-62 years) between March 15 and March 22, 2021. Of all participants, 38% had already been vaccinated, 41% stated a high willingness to vaccinate, 28% stated relatively less willingness to be vaccinated, 18% stated not to be vaccinated and 10% stated that they were not vaccinated.

As reported by the highly vaccinated participants, the main reasons for not vaccinating are difficulties in securing vaccine appointments, lack of information about the vaccination location and the distance to vaccination centers.

Regarding vaccine hesitation or severe unwillingness, reasons reported by participants included concerns about the safety and effectiveness of the vaccine, distrust of government policies, and disbelief that COVD-19 is a serious disease.

Weighted mean preferences (relative care services) for vaccination campaign characteristics in the total population (N = 2,985)

Weighted mean preferences (relative care services) for vaccination campaign characteristics in the total population (N = 2,985)

Public preferences for vaccinations

With regard to the preference for COVID-19 vaccination centers, the study participants showed the same willingness for pharmacies and at home compared to health facilities. A slightly negative preference for community venues and a strong negative preference for National Guard-supported mass vaccination sites were reported.

In comparison to the long waiting time (1 or 2 hours), the participants preferred immediate service. In comparison to online scheduling, the same preference was given for telephone and drop-in appointments.

A consistently negative preference for vaccine enforcement measures for air travel, work / school attendance, and group recreational activities was observed among participants. In addition, an inverse correlation between reluctance to vaccinate and willingness to vaccinate under enforcement was observed.

Regarding the vaccination schedule, participants indicated that vaccination with two doses is less preferred compared to vaccination with one dose. In this context, the strongest negative preference for annual vaccination programs compared to a single vaccine episode with long-term protection was reported.

No impact of community vaccine coverage on vaccination decisions was observed in participants with severely negative reactions to vaccination. In contrast, participants who were relatively less reluctant to get vaccinated or not to vaccinate were seen to have a positive impact of community vaccine coverage on vaccine-related decision-making.

Population subgroups based on vaccine preference

Six subgroups were identified based on vaccine preferences. Approximately 8% of the participants in the “single dose” group, 15% of the participants in the “single dose” group and 22% of the participants in the “vaccine once” group showed strong negative preferences for the two-dose vaccination, single-dose vaccination and annual vaccination, respectively.

About 9% of participants in the fourth group showed a strong preference for immediate service rather than a long wait (1 or 2 hours) in vaccination centers. In addition, around 13% of the participants in the “Social Proof” group stated that their willingness to vaccinate would increase if at least a few people in their community were vaccinated first.

About 32% of the participants in the “control averse” group showed a strong and consistently negative preference for the enforcement of vaccines. Vaccine enforcement was found to be the leading cause of hesitation and aversion to vaccines, especially among young people, Black / African American, and Republicans.

Study significance

According to the study results, promoting voluntary vaccination and offering a choice of brands and locations could increase public preference for COVID-19 vaccination.

* Important NOTE

medRxiv publishes preliminary scientific reports that are not peer-reviewed and therefore should not be considered conclusive, guide clinical practice / health-related behavior, or treated as established information.

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