Covid-19 is still deadlier for patients than influenza, finds study

By Jason Gale

Covid-19 isn’t “just a flu,” with a study of hospital patients finding that the virus was still 60% deadlier than influenza last winter.
 

Greater immunity against the coronavirus, better treatments, and different virus variants lowered Covid’s mortality risk to about 6% among adults hospitalized in the US last winter from 17-21% in 2020, researchers at the Clinical Epidemiology Center of the Veterans Affairs St. Louis Health Care System in Missouri found. That was still much higher than the flu’s death rate of 3.7%.

“This finding should be interpreted in the context of a two-to-three times greater number of people being hospitalized for Covid-19 versus influenza in the US in this period,” epidemiologist Ziyad Al-Aly and colleagues wrote in a letter Thursday in the journal JAMA. The research is based on an analysis of electronic health records in databases kept by the Department of Veterans Affairs, which operates the largest nationally integrated health care system in the US.

Covid has frequently drawn comparisons with influenza, another viral respiratory disease, including by former US president Donald Trump. The Centers for Disease Control and Prevention estimates that about 22,000 Americans died from influenza in the 2019-2020 flu season, whereas Covid killed about 350,000 in 2020. 

Compared with flu patients, those hospitalized with Covid had a greater risk of acute kidney injury, severe septic shock, life-threatening blood clots, and a range of dangerous cardiovascular complications, Al-Aly showed in a study in 2020. 

Bleeding and clotting complications, which can lead to stroke and heart attack, are more common in Covid patients, said Lekshmi Santhosh, an associate professor of clinical medicine at the University of California, San Francisco.

“People who are hospitalized with Covid often tend to have more multi-organ system complications than with influenza,” said Santhosh, a pulmonary and critical-care physician and medical director of a post-Covid clinic. “When folks are hospitalized with Covid, they sometimes are ‘tipping over’ from a fragile baseline state of health.”

Al-Aly’s analysis found the mortality risk was greater among unvaccinated users of the VA health system compared with those who had been immunized and boosted, underscoring the importance of the shots in reducing the risk of dying from Covid. VA users are mostly older, white males, which might limit how generalizable the findings are to other groups, the authors said.