High attack rate of COVID-19 in an organized tour group of vaccinated travellers to Iceland.

In a COVID-19 outbreak in a group of 25 twice-vaccinated Israeli travellers, the attack rate was 84%, despite negative preflight polymerase chain reaction tests. This extremely high breakthrough infection rate is attributed mainly to close and prolonged exposures during long bus drives. Masking, distancing and personal responsibility are required to avoid such outbreaks.