America faces a storm of 4 deadly viruses amid holiday travel

As millions return to work after the holiday season, the US is grappling with an alarming surge in respiratory illnesses and gastrointestinal infections - a phenomenon that experts are calling the “quad-demic.”  

A combination of flu - Covid-19, RSV (respiratory syncytial virus) and norovirus (sometimes called the stomach flu) - has seen a significant uptick since Christmas, with these viruses continuing to spread across the country.