As Connecticut surpasses the 50% mark for Connecticut residents ages 16 and over who are now fully vaccinated, the Department of Public Health today released data on vaccine breakthrough cases, which clearly show that the COVID-19 vaccines are highly effective at fighting the virus. So-called “vaccine breakthrough cases” occur when a person who has completed their vaccine series becomes infected with the COVID virus. The data show that cases of COVID-19 in fully vaccinated individuals are rare, with less than 0.1 percent of Connecticut’s fully vaccinated persons reported to DPH as having contracted the virus.