BEIJING, Dec 26 (Reuters) - In more than three decades of emergency medicine, Beijing-based doctor Howard Bernstein said, he has never seen anything like this.

Patients are arriving at his hospital in ever-increasing numbers; almost all are elderly and many are very unwell with COVID and pneumonia symptoms, he said.

Bernstein's account reflects similar testimony from medical staff across China who are scrambling to cope after China's abrupt U-turn on its previously strict COVID policies this month was followed by a nationwide wave of infections.

It is by far the country's biggest outbreak since the pandemic began in the central city of Wuhan three years ago. Beijing government hospitals and crematoriums also have been struggling this month amid heavy demand.

"The hospital is just overwhelmed from top to bottom," Bernstein told Reuters at the end of a "stressful" shift at the privately owned Beijing United Family Hospital in the east of the capital.