Vaccine effectiveness against SARS-CoV-2 transmission and infections among household and other close contacts of confirmed cases, the Netherlands, February to May 2021

de Gier, Brechje; Andeweg, Stijn; Joosten, Rosa; ter Schegget, Ronald; Smorenburg, Naomi; van de Kassteele, Jan; Hahné, Susan JM; van den Hof, Susan; de Melker, Hester E; Knol, Mirjam J; Hofhuis, Agnetha; Teirlinck, Anne; van Lier, Alies; Boudewijns, Bronke; Verstraten, Carolien; Willekens, Guido; Veldhuijzen, Irene; Polman, Jan; van de Kassteele, Jan; Alblas, Jeroen; van Heereveld, Janneke; Heijne, Janneke; Bulsink, Kirsten; Wielders, Lieke; van Asten, Liselotte; Jenniskens, Liz; Soetens, Loes; Mulder, Maarten; Schipper, Maarten; de Lange, Marit; Smorenburg, Naomi; Neppelenbroek, Nienke; van den Berg, Patrick; de Oliveira Bressane Lima, Priscila; van Gaalen, Rolina; Wijburg, Sara; van Iersel, Senna; de Bruijn, Siméon; Andeweg, Stijn; Wierenga, Sjoerd; Lanooij, Susan; Keijser, Sylvia; Smit, Tara; Klinkenberg, Don; Backer, Jantien; de Boer, Pieter; McDonald, Scott; Maxwell, Amber; Niessen, Annabel; de Gier, Brechje; Berry, Danytza; van Wees, Daphne; van Meijeren, Dimphey; Vos, Eric R.A.; Dijkstra, Frederika; Kemmeren, Jeanet; Ainslie, Kylie; Middeldorp, Marit; Kooijman, Marjolein; Knol, Mirjam; Zadeh, Shahabeh Abbas; Faber, Timor; van Hoek, Albert Jan; Geubbels, Eveline; de Melker, Hester; Wallinga, Jacco; van Gageldonk-Lafeber, Rianne; Hahne, Susan; van den Hof, Susan

Several studies report high effectiveness of COVID-19 vaccines against SARS-CoV-2 infection and severe disease, however an important knowledge gap is the vaccine effectiveness against transmission (VET). We present estimates of the VET to household and other close contacts in the Netherlands, from February to May 2021, using contact monitoring data. The secondary attack rate among household contacts was lower for fully vaccinated than unvaccinated index cases (11% vs 31%), with an adjusted VET of 71% (95% confidence interval: 63–77).