Brazil's Declining Vaccination Rates
Brazil, a recognized leader in global vaccination campaigns and public health, has observed a decline in vaccination coverage rates since 2017. A study published in the journal Health Policy and Technology analyzed public preferences regarding vaccine characteristics and non-pharmaceutical interventions, as well as the factors influencing individual vaccination decisions.
Background on Declining Coverage
Analysis of data from the Brazilian Ministry of Health indicates a gradual decrease in vaccination coverage rates since 2017. This decline varies across different vaccine types, including Meningococcal C, Hepatitis B, Pentavalent, Pneumococcal, and BCG, and is more pronounced in the North and Northeast regions of the country.
The World Health Organization's (WHO) Immunization Portal has documented the resurgence of some vaccine-preventable diseases.
This situation highlights the urgency of understanding the reasons behind Brazil's declining vaccination coverage, especially amid challenges like political polarization, the prominent role of social media, and the spread of misinformation.
Study Methodology
The research conducted the first Discrete Choice Experiment (DCE) in Brazil, focusing on a hypothetical future respiratory pandemic, similar to COVID-19. The study integrated preferences for government-imposed social restrictions and potential vaccines against respiratory viruses, alongside a broad set of sociodemographic data. This data included moral attitudes, risk perceptions, time preferences, and political opinions.
Between July and September 2022, a sample of 3,001 Brazilian participants was gathered online. The sample was selected to reflect the country's demographic diversity by age, gender, and geographic distribution, though it was primarily composed of individuals with a higher level of education than the average Brazilian population. Participants were presented with various scenarios involving different vaccine characteristics and measures restricting movement or social interaction, and asked to choose their preferred option or decline both.
Key Findings
Participants generally demonstrated high confidence in vaccines and the public health network.
Factors Affecting Vaccination Decisions:- Distrust in the government
- Political orientation
- Perceived risk of a future pandemic
- Social influence from family and friends
- Having a university degree
- Age
- Region of the country
The study identified four heterogeneous groups through latent class analysis, representing different behavior patterns:
- Highly Trusting (32%): Primarily young women with lower incomes, characterized by high trust in authorities and pro-vaccine attitudes.
- Moderately Trusting (29%): Tended to be older men with higher incomes and education, showing moderate trust in authorities but high trust in medical professionals, generally pro-vaccine.
- Highly Hesitant (20%): Young women with lower incomes, exhibiting low trust in authorities and medical professionals, high vaccine hesitancy, and susceptibility to social media influence.
- Moderately Hesitant (19%): Younger men with higher incomes and education, showing low trust in authorities but high trust in medical professionals, moderate vaccine hesitancy, and susceptibility to social media influence.
Implications
The study corroborates findings that political polarization is a critical determinant of health outcomes, as observed with vaccination adherence during the pandemic among more conservative groups.
As new health crises emerge, governments and health authorities will need to rethink communication strategies targeting vaccine-hesitant or resistant populations. Implementing dynamic systems for monitoring population preferences, such as annual state-level vaccine sentiment surveys, could allow public health decision-makers to identify attitude changes in real-time and adapt strategies quickly.
The results also emphasize the importance of building and maintaining public trust in health authorities, particularly when these institutions are perceived as technical, consistent, and politically independent, to mitigate the effects of political polarization on health behaviors.