RESUMEN
OBJECTIVE: This study examines the impact of the COVID-19 pandemic on both routine and non-routine vaccinations in infants during their initial 18 months of life, concurrently exploring the complex influence of sociodemographic factors. METHODS: A cohort study was conducted, involving 2007 children in two distinct periods: pre-pandemic (January-June 2018) and pandemic (March 2020-May 2021). Participants were classified into two cohorts: 962 children in the 2018 group and 1045 children in the 2020-21 group. Utilizing unconditional logistic regression, the association between vaccination (complete or non-routine) and socioeconomic factors was examined, with adjustments for potential confounding variables such as age, breastfeeding, gestational age, and twins. RESULTS: The study's analysis reveals that in the post-pandemic period, mothers were three times more likely to opt for non-routine vaccines (95% CI 2.25-4.23). However, no significant alterations were observed in routine vaccination rates. Protective factors for complete vaccination included having an employed mother, higher education, and a medium-to-high income. Conversely, a higher income was associated with a reduced likelihood of complete vaccination (OR 0.34, 95% CI 0.20-0.59). CONCLUSION: Contrary to initial expectations, this study concludes that the COVID-19 pandemic did not have a substantial impact on childhood complete vaccination rates. Nevertheless, a noticeable increase in the choice of non-routine vaccination was observed. Sociodemographic factors, such as maternal education, income, and employment status, emerged as key influencers, particularly in the context of deciding on non-routine vaccinations.