Health officials are worried about a severe “twindemic” this year, when influenza and coronavirus cases increase at the same time. What parallel surges could mean for an already exhausted health-care system and efforts to end the pandemic.Read more:Last year, similar warnings were made about a potential “twindemic.” Instead, the flu practically vanished. Health officials say this year could be different: Much of the country is up and running again, and 2020’s mild flu season means population immunity is probably lower. That’s why officials are urging Americans to get the flu shot. “The flu shot is proven effective and has been shown year after year to save lives,” says health reporter Fenit Nirappil. “And that's going to be particularly acute this year when we're also dealing with a new strain of coronavirus.”