Comprehensive assessment of the impact of universal rotavirus vaccination program on the burden of diarrheal disease in children after 10 years of implementation in Argentina

Abstract

[ABSTRACT]: Background: In 2015, Argentina introduced the monovalent rotavirus vaccine into its National Immunization Program with a two-dose schedule at 2 and 4 months of age. This study assessed the impact of the universal rotavirus vaccination program on the burden of diarrheal disease in children under five years of age over a ten-year period, including the effects of the COVID-19 pandemic.

Methods: A mixed ecological time-trend analysis was conducted using national and regional secondary data from surveillance and health information systems. Six indicators were evaluated: outpatient acute diarrhea cases, hospitalizations due to diarrhea, diarrhea-related deaths, intussusception hospitalizations in infants, laboratory-confirmed rotavirus cases, and rotavirus vaccine coverage. Trends were compared across four periods: pre-vaccination (2010-2014), post-vaccination pre-COVID-19 (2016-2019), during COVID-19 (2020-2021), and post-COVID-19 (2022-2024).

Results: Compared to the pre-vaccination period, acute diarrhea rates declined by 59.6%, hospitalizations by 47.6%, and mortality by 59.7%. Laboratory-confirmed rotavirus positivity fell by 55.2%, with the most pronounced reductions observed in infants under one year of age. Although partial rebounds were noted post-COVID-19, all indicators remained below baseline levels. Intussusception hospitalizations in infants decreased by over 30% nationally, and no region showed rates exceeding pre-vaccine levels. Vaccine coverage declined during the pandemic and showed incomplete recovery. Statistical analyses confirmed significant differences by age group and period for most indicators, particularly highlighting the persistent vulnerability of infants to severe outcomes.

Conclusions: Ten years after the introduction of universal rotavirus vaccination in Argentina, a substantial and sustained reduction in the burden of diarrheal disease was observed across multiple indicators. While regional variability and post-pandemic fluctuations were noted, the overall benefit-risk profile of the vaccine remains strongly favorable. Continued efforts to strengthen vaccine coverage and surveillance systems are essential for consolidating these gains and ensuring timely detection of potential adverse trends.