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 ...

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 ...

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 research from scientists at La Jolla Institute for Immunology (LJI) suggests people who received COVID-19 vaccines and then experienced "breakthrough" infections are especially well armed against ...

A growing proportion of COVID-19 deaths are occurring among the vaccinated, a new ABC News analysis of federal data shows. In August of 2021, about 18.9% of COVID-19 deaths occurred among the ...

In the early days of the coronavirus vaccine rollout, scientists were hopeful it might herald the long-awaited turning point of the pandemic, not only bringing the threat of severe disease, ...

Researchers discovered that people who experienced symptomatic breakthrough infections develop T cells that are better at recognizing and targeting SARS-CoV-2, including the Omicron and Delta variants ...