Rep. Jason Crow (D-Colo.) announced on Sunday night that he tested positive for a breakthrough COVID-19 infection but is experiencing mild symptoms. “I just returned from an official congressional delegation visit to Ukraine and tested positive for a breakthrough COVID infection,” Crow, who is vaccinated, wrote on Twitter. “I’m thankful to be fully vaccinated and boosted and experiencing only mild symptoms (the vaccine is safe and effective).” While COVID-19 vaccines are somewhat effective at preventing infection, serious illness, and death, they are not 100 percent effective, and some individuals who are fully vaccinated can still contract the disease, the Centers for Disease Control and Prevention (CDC) has said. This is referred to as a “vaccine breakthrough infection.” An individual with a vaccine breakthrough infection is still at risk of spreading the virus to others but is less likely to develop serious side effects compared to someone who is unvaccinated, as per the CDC. Crow, a Democrat, also …