Determinants of COVID-19 Vaccine Hesitancy in Portuguese-Speaking Countries: A Structural Equations Modeling Approach

"[O]bjective and assertive approaches are needed to overcome misinformation about vaccines, particularly on social networks....Messages are crucial but not sufficient, especially depending on the source. Therefore, bringing vaccine development processes closer to people, from the beginning, may be useful."

COVID-19 vaccine hesitancy (VH) has caused concerns among health authorities, including those in Portuguese-speaking countries. Misinformation and the massive spread of false information, conspiracy theories, and rumours about COVID-19 vaccines, in addition to political polarisation, are among the main factors that have been worrying countries, even before the beginning of vaccination, and have directly and indirectly strengthened VH and contributed to delayed reach of collective immunity. This study aimed to estimate the prevalence and factors associated with COVID-19 VH in Portuguese-speaking countries in an effort to inform the creation of more effective strategies for increased vaccine acceptance.

An observational, analytical study was conducted through online data collection (Web survey) with 6,843 individuals from seven countries whose official language is Portuguese (Angola, Brazil, Cape Verde, Guinea-Bissau, Mozambique, Portugal, and São Tomé and Príncipe) from May to August 2020. A Directed Acyclic Graph (DAG) was constructed to represent the conceptual structure and the study hypotheses. Key elements/definitions:

• COVID-19 misinformation (MIS): misinformation caused by incorrect information related to the COVID-19 pandemic, with or without any purpose of intentionally causing harm to someone. It ranges from the dissemination of incorrect general beliefs (GB) related to COVID-19, such as advice on the ingestion of medicines or herbal medicines without scientifically proven efficacy, to politically motivated conspiratorial beliefs (CB) about, for example, the ineffectiveness of prevention and control measures. COVID-19 misinformation has been shown to increase fear, induce suffering, produce high levels of stress, intensify social conflicts, and cause direct damage to people's health, with social networks being important sources of this content.
• COVID-19 individual responses (CIR): COVID-19 coping strategies adopted by people daily, which depend on people's perception of risk and are strongly influenced by the type of information received - whether from close family and peers, social networks, or official government agencies. It is noteworthy that MIS can generate disastrous responses at the individual level. Thus, individual responses guided by quality information are considered crucial to the success of the global response to the COVID-19 crisis.
• COVID-19 suffering (COVS): anguish, fear, anxiety, and stress that may result from the risk experienced by people in their daily lives of being infected by SARS-CoV-2 or even from preventive measures, such as social isolation.
• Vaccine conspiracy beliefs (VB): ideas intended to diminish trust in vaccines, governments, healthcare professionals, and the pharmaceutical industry. VB accentuate fear and mistrust about vaccines and, combined with MIS, can make people decide to forgo vaccination. These conspiracy theories are widespread on social networks and contribute to VH.
• Perceived stress (PS): high levels of COVID-19-related perceived stress associated, for example, with ineffective communication on the part of authorities - to the detriment of scientific recommendations.

Having used Measurement Models, Exploratory Factor Analysis, Exploratory Structural Equation Models, and Confirmatory Factor Analysis for the data analysis, the researchers found that the overall prevalence of COVID-19 VH in Portuguese-speaking countries was 21.1%, with the following showing a statistically significant direct effect for VH: VB, PS, MIS, and CIR.

The effect of MIS and CIR for VH was greater among men and of PS and VB among women; the effect of PS was greater among the youngest and of VB and CIR among the oldest. Women, older adults, people with a high educational level, and people who had lost a family member or a friend due to COVID-19 were more likely to hesitate to be vaccinated. Per the researchers, these characteristics differ from studies carried out in developed countries and reinforce the fact that, although VH is a global problem, specificities of different population groups must be considered and understood.

In short, VB were identified as the construct most strongly associated with VH in the general model and seem to relate to a recently observed global pattern in which availability and access to information foster in individuals a (false) sense of control over diseases that outweigh the need for vaccines that people worry are produced by "suspicious laboratories and countries". Notably, among the VB, the belief that "the vaccine can cause other diseases, such as autism or autoimmune diseases" (19.1%) stood out.

Reflecting on the findings, the researchers note that, in the context of COVID-19-related VH, social media contributes to the creation of affective-informational bubbles of disinformation guided by an algorithmic logic, in which people seek information that reinforces their precepts and alleviates their fears and tensions, even if they are based on error. It may have been because of this factor that the variables CB and GB together formed a superior construct that may have determined, in this study, the individual response of the subjects and the results regarding VH. For example, a low level of effective CIR resulted in VH because risk perceptions (beliefs about potential harms) are predictors of adult vaccination behaviour.

In conclusion: "The expanded understanding of factors such as misinformation and individual practice/response affecting the collective immunization of COVID-19, especially in a pandemic condition, requires different response strategies....It is necessary to respond quickly, fast, and accurately to the challenges posed by vaccination hesitation, especially in Portuguese-speaking countries, as the determinants are configured as socio-cognitive vulnerabilities added to acquired, poorly substantiated, and distorted knowledge. In addition to a health surveillance discussion, the governance systems of these countries must act in an articulated manner, modulating and softening these factors to obtain better results, an active immunization of the population, and to demystify beliefs."