Predicting people's decision to get vaccinated in times of Covid-19

The concept of vaccine hesitancy predates COVID-19 and has existed for as long as vaccines have existed (Ray, 2021). The World Health Organization has identified vaccine hesitancy as one of the ten greatest threats to public health, highlighting the need to study, understand, and target this construct. The success of COVID-19 vaccines will depend on vaccinating a large percentage of the population to achieve herd immunity, taking into account that there is a group of individuals who cannot be inoculated for various reasons related to their health. This goal highlights the need for rigorous public health campaigns that speak to individuals who are hesitant about the vaccine and to do so it is necessary to understand what leads to vaccine hesitancy (WHO, 2019). Furthermore, vaccine hesitancy has increasingly become part of the news alongside those about the COVID-19 pandemic. Despite the rapid development of a COVID-19 vaccine, its wide acceptance is still worrying, representing a barrier to achieving herd immunity (Ray, 2021). Vaccination, indeed, is recognized as one of the most successful public health measures, yet it is perceived as dangerous and unnecessary by an increasing number of individuals (Dubè et al., 2013).

The World Health Organization, its COVID-19 Vaccines Working Group and with the support of the Strategic Advisory Group of Experts (SAGE) on Immunization, continue to review the emerging evidence on the need for and timing of a booster dose for the currently available COVID-19 vaccines. The goal of a booster dose is to restore the efficacy of the vaccine when this is no longer deemed sufficient. In fact, booster doses are administered to a vaccinated population that has completed a series of primary vaccinations and over time immunity and clinical protection have fallen below a rate deemed sufficiently adequate. Evidence of both public and individual health benefits, and obligations to ensure global equity in access to vaccines as a means of reducing the prolongation of the pandemic should guide policy decisions on the booster dose (www.who.int).

Vaccine hesitancy can affect motivation, causing people to refuse vaccines for themselves or their children. It can be caused by an individual, group, and contextual influences, as well as any vaccine-specific problems. In addition, vaccine hesitancy can rapidly undermine vaccination coverage in specific settings, and it is important that all countries put their efforts to understand both the extent and nature of hesitancy on an ongoing basis. Consequently, each country should develop a strategy to increase vaccine acceptance through continued community involvement and trust-building, active hesitancy prevention, regular national assessments of concerns, and crisis response planning. This process can play a key role in improving the quality of services in a way that builds trust and will create benefits for vaccination coverage (MacDonald, 2015). Furthermore, all interventions that aim to increase vaccine acceptance and demand should be systematically monitored and evaluated to guide adjustments and any expansion of successful strategies (www.who.int).

One of the difficulties encountered by health promoters in the development of effective programs to change health-related habits, specifically vaccine-related to prevent Covid- 19, is the lack of sufficient information regarding the main determinants of such a behavior in a certain population. This information is needed to change the influencing factors in the desired direction. Consequently, it is necessary to initiate studies on the determinants of certain behavior intentions based on behavioral theories and their related models (www.who.int).