The SIOG COVID-19 working group recommendations on the rollout of COVID-19 vaccines among older adults with cancer. Issue 5 (June 2021) - Mislang, Anna Rachelle; Soto-Perez-de-Celis, Enrique; Russo, Chiara; Colloca, Giuseppe; Williams, Grant R.; O'Hanlon, Shane; Cooper, Lisa; O'Donovan, Anita; Audisio, Riccardo A.; Cheung, Kwok-Leung; Sarrió, Regina Gironés; Stauder, Reinhard; et al.