Why didn't people get vaccinated against COVID-19? Results from a nationwide survey among Mexican adults.

Background: Mexico is one of the countries with the highest case-fatality ratio due to COVID-19.

Objective: Explore the reasons for not getting vaccinated against COVID-19.

Material and methods: A nationwide telephone survey, comprising all 32 states of Mexico, was conducted to examine associations between inoculation against COVID-19 and other characteristics, the chi-square test and logistic regression analysis were applied.

Results: Out of 3 126 adults, 68% reported complete vaccination, 21% the first dose, 11% remained unvaccinated. Using logistic regression models: place of residence -Other central state and State of Mexico-, being single, lower education level, younger age, lower BMI, not getting tested for COVID-19, and the perception of COVID-19 as unreal and not severe, were all significantly associated with non-vaccination, i.e. not receiving any dose of anti-COVID vaccine. The predominant reasons for not getting vaccinated were: 63% "external barriers" (e.g., not being able to attend an appointment), and 37% "internal motives" (e.g., considering that the vaccine does not work).

Conclusions: The causes of non-vaccination against COVID-19 are related to social and geographical determinants. Addressing external barriers is necessary to promote equity in vaccination. Reviewing the results in the context of earlier studies on the willingness to vaccinate, the gap between intention and vaccination is notable.