With flu season approaching in the US, murmurs of a potential "twindemic" brewing are once again starting to surface. "This could very well be the year," Vanderbilt infectious disease expert Dr. William Schaffner told NPR's Up First on Friday, "we have a surge in COVID, and simultaneously an increase in influenza." One big reason that infectious disease experts are especially worried this year is because Australia's 2022 flu season was pretty bad, and what happens during the Southern Hemisphere's winter flu surge often forshadows the US flu season well.