Doctors have long been concerned regarding the potential impact of a “twindemic” — with influenza cases rising as covid-19 cases threaten to overwhelm hospitals — and called on people to get flu shots and coronavirus vaccinations. On the other hand, “flurona” refers to when one person has both respiratory infections at the same time — which health officials say is a possibility as cases of the highly contagious omicron variant of the coronavirus surge this winter across the world.