Adolescents With Breakthrough COVID-19 Infections Requiring Hospitalization: A Multicenter Retrospective Study

Area of Science:

• Pediatrics
• Infectious Diseases
• Vaccinology

Background:

• Widespread COVID-19 vaccination has led to a significant decline in cases.
• Adolescents (≥12 years) in Turkey were included in a nationwide vaccination program starting August 2021.
• The study evaluates the impact of this program on adolescent hospitalizations for COVID-19 and MIS-C.

Purpose of the Study:

• To determine the effect of the COVID-19 adolescent vaccination program on hospitalizations.
• To compare COVID-19 and MIS-C hospitalizations between the pre-vaccination and vaccination periods.
• To compare clinical features and severity of breakthrough COVID-19 infections versus unvaccinated adolescents.

Main Methods:

• Retrospective multicenter study comparing hospitalization data from two 12-month periods: pre-vaccination (PVP) and vaccination (VP).
• Analysis of hospitalizations for COVID-19 and MIS-C in children aged 0-18 years.
• Comparison of characteristics, risk factors, and outcomes for hospitalized adolescent breakthrough infections (12-18 years) versus unvaccinated peers during the VP.

Main Results:

• Adolescent hospitalizations (12-18 years) decreased from 35.4% in PVP to 18.6% in VP (RR: 0.6467, p < 0.001).
• Breakthrough COVID-19 cases were older, less frequently hospitalized for COVID-19 (OR: 0.347), and predominantly asymptomatic/mild (OR: 5.718).
• Fewer breakthrough cases required Pediatric Intensive Care Unit (PICU) admission (OR: 0.188), with most occurring within three months of the last vaccine dose.

Conclusions:

• The COVID-19 vaccination program significantly reduced adolescent hospitalizations for COVID-19 and MIS-C in Turkey.
• Vaccine breakthrough infections in adolescents are generally less severe than in unvaccinated individuals.
• Findings support the importance of adolescent COVID-19 vaccination and may influence vaccine hesitancy.