Vaccine effectiveness against severe acute respiratory infections (SARI) COVID-19 hospitalisations estimated from real-world surveillance data, Slovenia, October 2021

We estimated vaccine effectiveness (VE) against severe COVID-19 during October 2021, using Slovenian surveillance data. For people fully vaccinated with any vaccine in age groups 18-49, 50-64, >= 65 years, VE was 86% (95% CI: 79-90), 89% (85-91), and 77% (74-81). Among >= 65 year-olds fully vaccinated with mRNA vaccines, VE decreased from 93% (95% CI: 88-96) in those vaccinated <= 3 months ago to 43% (95% CI: 30-54) in those vaccinated >= 6 months ago, suggesting the need for early boosters.