LAS VEGAS, NEVADA -- A California couple says they were fully vaccinated, but still contracted COVID-19 while on vacation as experts say breakthrough cases are possible, especially with the delta ...

MARIN COUNTY, Calif. -- As the Delta variant spreads, we are learning more about breakthrough COVID-19 cases. Numbers from California's state health department help put into perspective what the ...

NEW YORK -- As Americans brace for the possibility of another difficult winter ahead in the nation's fight against coronavirus, there is a renewed sense of urgency to get as many people inoculated and ...

In an interview with WRAL News, Dr. Anthony Fauci said the Delta variant will cause some breakthrough cases in vaccinated people, but he doubts the CDC will issue a central recommendation for ...

Professional sports leagues are uniquely positioned to track breakthrough Covid cases because they test thousands of athletes consistently, according to Dr. Robby Sikka, a physician who has worked ...

More than 99.99% of people fully vaccinated against Covid-19 have not had a breakthrough case resulting in hospitalization or death, according to the latest data from the US Centers for Disease ...

The true prevalence of breakthrough COVID-19 cases is difficult to track due to a lack of comprehensive testing and surveillance, but a new analysis from The Wall Street Journal suggests infections ...

In the phase 3 AZD1222 COVID-19 vaccine trial, anti-Spike (vaccine-matched and Delta) binding IgG antibody concentration and neutralizing antibody (nAb) titer (vaccine-matched+D614G and Delta), ...

The poet Marjory Wentworth, who normally moves at roadrunner speed, languished at home last week exhausted and coughing. It felt surreal. She couldn't possibly have COVID-19. The longtime South ...

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center. At a recent town hall meeting in Cincinnati, Ohio, President Joe Biden was asked about COVID-19 ...