by Isabelle TOURNÉ PARIS, France (AFP) — With new versions forcing vaccine makers to re-test jabs, the virus that causes Covid-19 has proven highly unpredictable. But the latest variant to sweep the globe has persuaded some experts that long hoped-for collective immunity is in sight, and that the virus may be evolving into a relatively benign seasonal illness. Omicron has proven particularly contagious, infecting people thought to have immunity conferred by vaccines or a bout […]