Our survey revealed the attitudes of a Japanese population toward COVID-19 vaccination as of December 2020, in which nearly 60% of the respondents were willing to become vaccinated. Safety concerns regarding the vaccines were most common among respondents unwilling to get vaccinated. These results support findings in previous studies conducted after our survey, in which 62.1% of the participants in January 2021 (Machida et al. 2021) and 74% of the participants in February 2021 agreed to receive COVID-19 vaccines in Japan (Lacey 2021). Therefore, there appears to be an increasing trend in the demand for vaccines among individuals that began prior to the start of the vaccination programs in Japan, and it has continued to increase. Nonetheless, many of our respondents were still undecided, given that only 10.5% said they “definitely agree” to receive COVID-19 vaccines. Among the national affiliations of participants responding to a global survey administered in December 2020, Japan showed the lowest proportion of those who “strongly agreed” to receive the COVID-19 vaccine (11%) (Boyon 2020).
The Japanese might consider the available data carefully before making a final decision. The second most common reason given by our respondents unwilling to get vaccinated was “lack of information on safety and efficacy.” More than 80% of the respondents willing to get vaccinated did not want to receive it immediately, because they were waiting for clearer data on the vaccines’ adverse effects and efficacy. Safety concerns are a critical consideration for individuals in the decision-making stage of COVID-19 vaccination (SteelFisher et al. 2021). Before Japan experienced the human papillomavirus vaccination crisis (Larson 2020) and other medication-related health injuries, several people stated that they were skeptical of vaccines in general (de Figueiredo et al. 2020). In addition, information with no scientific evidence has spread to support the perception that COVID-19 vaccines are unsafe (Horton 2020). More information on the COVID-19 vaccine and how it is administered can influence attitudes. The provision of information on vaccines will need to be transparent and updated frequently to keep pace with accumulating evidence.
Vaccine acceptance will change in each country depending on various factors, including the spread of COVID-19 infection, approval status of vaccines or rollout, and access to COVID-19 vaccines (Johns Hopkins Center for Communication Programs 2021). In Japan, the COVID-19 vaccine acceptance rate has continued to increase after our survey due to the implementation of vaccination programs, the spread of COVID-19 infection among younger people, and mass media reports of other countries’ high completed vaccination rates. Our data also provided information on the rate of acceptance of COVID-19 vaccines prior to the implementation of vaccination programs in Japan.
According to our survey, the younger group’s willingness to vaccinate was less than the older group’s willingness, which was similar to the findings of previous studies on COVID-19 vaccine acceptance (Machida et al. 2021). Among the possible reasons are the features of COVID-19, in which older individuals and those with underlying medical conditions tend to develop severe cases more frequently than individuals with other demographic characteristics (World Health Organization 2020a). Furthermore, more than 90% of our respondents knew this information, which might have contributed to enhanced vaccine acceptance among the older group; conversely, it could have enhanced the younger group’s perception that the vaccine did not concern them. Our survey showed that the hesitation to receive COVID-19 vaccines among the younger group included “I do not think that I will become seriously ill even if I get infected with COVID-19” (n = 38, 10.9% of the respondents in the younger group who were not willing to receive the COVID-19 vaccine). Another potential reason could be people’s past experiences with vaccination. Many respondents in the older group in our survey could have accumulated more experience receiving vaccinations than in the younger group (Shahrabani and Benzion 2012). For instance, our survey showed that a higher proportion of respondents in the older group had a seasonal influenza shot in the past year than those in the younger group. The Immunization Act, which had required Japanese citizens to take specific vaccines, was amended in 1994 after class action suits relating to several vaccinations were filed against the Japanese government. Accordingly, vaccination policies shifted from mandatory to a best effort obligation for Japanese citizens. Elderly respondents could have experienced mandatory vaccination according to the former Immunization Act. In contrast, younger people might not have enough vaccination experience to have developed a trust in vaccine safety and efficacy. Younger respondents who disagreed being vaccinated were more likely than older people to select the following reasons regarding the need for vaccination: “I do not think that I will become seriously ill even if I become infected with COVID-19” or “I do not think the COVID-19 pandemic is as serious as people say.” The younger respondents in our survey did not appear to prioritize vaccination as an approach to defeating the COVID-19 pandemic. The older group’s more preferable attitudes toward the public interest and the literacy gap of vaccines between the age groups could have led to differences in their attitudes.
The COVID-19 pandemic situation has been changing rapidly. Mutations in the virus strains have led to a significant increase in severe cases among young people who were previously not considered to be at high risk. This change might influence younger people to take greater precautions against COVID-19 as they realize their own risk of becoming severely ill from COVID-19. If these risks become less significantly different between age groups, the current prioritization of COVID-19 vaccination for older people as a higher priority should be reconsidered (Matsui et al. 2021). The ethical principle supporting the prioritization of high risk cases is the “rule of rescue,” which aims to rescue identifiable individuals facing avoidable death or serious harm (McKie and Richardson 2003). Under this principle, a person has a determined obligation of beneficence toward another person when each of the following conditions is satisfied: the other person is at risk of significant loss of or damage to life, health or some other interest; a rescuer’s action is needed to prevent the other person’s loss; a rescuer’s action has a high probability of preventing the other person’s loss; a rescuer’s action would not present significant risks, costs, or burdens to the other person; and the benefit that the other person can be expected to gain outweighs any harms, costs, or burdens that person is likely to incur (Beauchamp and Childress 2001). If all people were at the same risk of severe conditions, the current prioritization of COVID-19 vaccination would not be supported by the “rule of rescue” principle. Adjustment of vaccination priority according to the current COVID-19 pandemic situation might be based on other ethical principles, such as the “fair innings argument,” which states that everyone has an equal chance to experience a certain span of years, called the “fair innings,” which we consider a reasonable lifespan (Persad et al. 2009). Following this principle, people in the fair innings stage should be treated equally, whereas those who are experiencing life beyond the fair innings stage have lower priority. In our survey, most respondents generally supported the current vaccination priority policy. However, a higher proportion of respondents in the younger group than those in the older group responded that they thought their priority was inappropriate. These opinions could change if the age group of the people who become seriously ill changes. Given that the younger group tended to place more importance on personal interests than on public interests, it will be necessary to evaluate public opinions, including those of younger people, about priorities because the target age groups’ potential for severe COVID-19 infection can change.
In terms of future perspectives, we can first reconsider vaccine policies during the global pandemic era. Most countries have left the decision to receive COVID-19 vaccination to the individual. The World Health Organization has said that persuading people on the merits of a COVID-19 vaccine would be far more effective than attempting to make it mandatory (World Health Organization 2020b; WHO Ethics and COVID-19 Working Group 2021). In contrast, certain countries have introduced a mandatory vaccination policy. Italy approved an emergency decree on April 2021 to make the COVID-19 vaccination mandatory for healthcare workers (Paterlini 2021). In the USA, hospital employees resigned or were fired after refusing to receive the COVID-19 vaccine (Allen 2021). Furthermore, the Philippine president threatened to order the arrest of Filipinos who refused to receive the COVID-19 vaccination (Associated Press 2021). Our survey revealed that only 17% of respondents agreed to a mandatory COVID-19 vaccination law, which suggests that it might be hard to gain broad public support. Nevertheless, more than 60% of respondents agreed to the vaccination of the entire population regardless of legal mandate. The requirement for an immunity passport introduces similar challenges regarding controversial mandatory vaccinations (Kofler and Baylis 2020). The idea is that such certificates would be issued to those who have recovered from COVID-19 and have tested positive for antibodies to SARS-CoV-2. Authorities would lift restrictions on those who are presumed to have immunity in their daily life. This approach is not a direct legal mandate for vaccination but indirectly presses it by placing societal disadvantages, including risks of discrimination. The opposition to a mandatory vaccination policy stems from the belief that it violates an individual’s right to refuse unwanted treatment. It could be ethically preferable to incentivize COVID-19 vaccine uptake rather than implementing a direct or indirect mandatory vaccination requirement (Savulescu 2021).
There have been immense efforts to promote COVID-19 vaccine development and distribution globally and in specific communities where there is a high rate of vaccine hesitancy (World Health Organization 2021). Considering the scientific evidence and public support for COVID-19 vaccination, interventions to enhance vaccination rates would be acceptable. Besides disseminating appropriate information on COVID-19 vaccination to the public, the nudge approach has been suggested as an alternative to mandatory vaccination (Patel 2021). Nudges are subtle changes in how choices are offered without mandates, which can avoid the ethical challenges related to mandatory vaccination (Dubov and Phung 2015). If a large number of individuals are unwilling to vaccinate due to normalcy bias, which is based on the fact that they did not get infected with COVID-19, then a nudge approach is likely to be acceptable. If we need to take the vaccine continuously, we need to present the same nudge several times to promote it. However, repeating nudges can be difficult to sustain because people show decreased responses to the same stimulations, a phenomenon known as “habituation” (Thompson and Spencer 1966). Assuming that the supply of vaccines will stabilize and that continuous vaccination will be recommended, it is necessary to consider ways to promote vaccination, including nudging approaches that can avoid habituation.
Second, there appears to be a gap between participants in COVID-19 vaccine trials and the prioritized population in real-world vaccination. Currently, younger people take on the burden of clinical trials, whereas older people receive the benefits of the clinical trials before younger people. Given that the clinical trials have included a small proportion of participants aged over 70 or 75 years, the safety and efficacy for older people needs to be evaluated more precisely. From safety and ethical perspectives, the population who takes on the burden of vaccine clinical trials and those who receive benefits with high priority should be matched as much as possible. Regarding COVID-19 vaccination, older people would be more confident in taking a vaccine when the data on the safety and efficacy of the vaccines are demonstrated by the clinical trials in which an older population is enrolled. As shown in our survey and previous research (SteelFisher et al. 2021), concerns about adverse reactions to vaccines and lack of information on their safety and efficacy are primary reasons for not being willing to take them. Vaccine clinical trials for specific groups, such as children and pregnant women, have been conducted (Pfizer and BioNTech 2021a, b). Due to Japan lagging behind other countries in vaccine development, a strategy might need to be developed to balance the unfairness of sharing the research burden among participants of vaccine clinical trials and the top-priority population for the vaccination. Given that the older population is a high priority for COVID-19 vaccination efforts, Japanese research teams can evaluate the safety and efficacy of the vaccines in the older population by conducting clinical trials.