Homologous and Heterologous Prime-Boost Vaccination: Impact on Clinical Severity of SARS-CoV-2 Omicron Infection among Hospitalized COVID-19 Patients in Belgium, Meurisse, Marjan, Catteau Lucy, Van Loenhout Joris, Braeye Toon, De Mot Laurane, Serrien Ben, Blot Koen, Cauët Emilie, Van Oyen Herman, Cuypers Lize, et al. , Vaccines, Feb-07-2023, Volume 11, Issue 2, (2023)