COVID-19 vaccines were never promised to be 100% effective, and experts are united in saying they remain the best way to combat the pandemic.
But a growing number of breakthrough cases - the term used to describe people who become infected by the coronavirus despite being fully vaccinated - is drawing attention to how much research is still needed to better understand the virus.
Breakthrough infections were thrust further into the spotlight this past week as more high-profile, fully vaccinated individuals across the nation - including Chattanooga Mayor Tim Kelly - announced they had tested positive for COVID-19. Kelly, 54, tweeted Wednesday that he had "mild, allergy-like symptoms" thanks to the vaccine preventing a more serious case.
"We knew we were going to see these breakthrough infections, but the important thing is to look at what's happening to these people," said Dr.