This study aimed to estimate vaccine effectiveness against SARS-CoV-2 Delta and Omicron infection (VE-infection) and transmission (VE-infectiousness) within households in the Netherlands. Data from the VASCO study (July 2021-August 2022) were analyzed using generalized estimating equations. During the Delta period, VE-infection for primary vaccination was 47% and VE-infectiousness was 70%. During the Omicron period, VE-infection was negative for both primary series and booster vaccinations, while VE-infectiousness was 45% and 64%, respectively. The study concludes that COVID-19 vaccination is effective against infectiousness of Delta and Omicron, supporting booster vaccination for those in close contact with vulnerable individuals.

Christina E Hoeve, Brechje De Gier, Anne J Huiberts, Hester E De Melker, Susan J M Hahné, Susan Van Den Hof, Mirjam J Knol