"The groundwork of all happiness is health." - Leigh Hunt

More evidence suggests there’s a “long flu.”

December 19, 2023 – You can have never heard of it, but perhaps you've had it before. Further evidence suggests that the “long flu” is an actual phenomenon. A big study shows that some people's symptoms last at the least 4 weeks or longer after they're hospitalized for the flu flu.

Researchers compared the long flu to the long COVID-19 illness and located that the long flu occurred less incessantly and was less severe overall. This difference could possibly be because flu (also called influenza) primarily affects the lungs, while COVID can affect quite a lot of organ systems within the body.

Researchers were surprised that each long flu and long COVID were related to a greater burden of antagonistic health effects in comparison with each primary infections.

“I think that COVID and long-COVID have made us realize that infections have long-term consequences and that the consequences of these long-term consequences are often much greater than the consequences of acute illness,” said Ziyad Al-Aly, MD, senior writer of the study and director of research and development on the VA St. Louis Health Care System.

“I know I shouldn’t be surprised after dealing with long-COVID for the last four years. But I am in awe of the impact these infections can have on the long-term health of those affected,” said Al-Aly, who can also be a clinical epidemiologist at Washington University in St. Louis.

Al-Aly and his colleagues Yan Xie, PhD, and Taeyoung Choi, MS, analyzed medical records from the U.S. Department of Veterans Affairs. They compared 81,280 people hospitalized with COVID to 10,985 people hospitalized with flu before the COVID pandemic. They checked as much as 18 months after the initial infections to see who developed long flu or long COVID symptoms.

The The study was published online this month in The Lancet Infectious Diseases Diary.

“It's an interesting study,” said Aaron E. Glatt, MD, chair of the department of medication and hospital epidemiologist at Mount Sinai South Nassau in Oceanside, N.Y., who was not involved within the research.

“The concern with many viruses is that they can have long-term consequences,” said Glatt, who can also be a member of the Infectious Diseases Society of America. He said the potential of long-term flu symptoms isn't recent, “but it's nice to have more data.”

People hospitalized with COVID had a 50% higher risk of death throughout the study period than people hospitalized with flu. Put one other way, for each 100 people hospitalized with COVID, about eight more people died in the next 18 months than those hospitalized with flu. Hospitalizations and ICU admissions were also higher within the long COVID group – 20 people more and nine people more, respectively, per 100 people hospitalized with COVID.

Further research is required, said Glatt. “For many of these viruses, we don't understand what they do to the body.” A prospective study to see, for instance, whether antiviral treatments make a difference could be useful, he noted.

Al-Aly and colleagues would really like to conduct further studies.

“We need to better understand how and why acute infections cause long-term illness,” he said, noting that he also desires to explore ways to stop and treat the long-term effects.

“There is still much work to be done and we are committed to doing our best to develop these answers.”