COVID-19 vaccines are effective at preventing illness and death; rare infections in vaccinated people can still occur, as seen in the Celebrity Millennium cruise
Clinical trials and ongoing monitoring of COVID-19 vaccination campaigns showed that people vaccinated against COVID-19 are less likely to get infected. Given that no vaccine effectiveness is 100% effective, some vaccinated people are expected to get infected nonetheless. Vaccines are still useful even for infected persons as they prevent serious illness and hospitalization.