Serial Intervals for SARS-CoV-2 Omicron and Delta Variants, Belgium, November 19-December 31, 2021., Kremer, Cécile, Braeye Toon, Proesmans Kristiaan, André Emmanuel, Torneri Andrea, and Hens Niel , Emerg Infect Dis, 2022 Aug, Volume 28, Issue 8, (2022)