By Conn Hastings, science writer

Image: Corona Borealis Studio/Shutterstock.com

A new study shows the long-term implications of severe Covid-19 infection, with such patients demonstrating significantly increased chances of death in the 12 months following the illness. The majority of deaths occurred for a wide variety of reasons, suggesting that severe infection damages overall health. The stark findings highlight the need to reduce the numbers of severe infections through vaccination.

Can long Covid kill? Striking findings presented in a new study published to Frontiers in Medicine show that patients who survive severe Covid-19 have more than twice the risk of dying over the following year, compared with those who experience mild or moderate disease or remain uninfected. Unusually, the increased risk of dying was greater for patients who are under 65, and only 20% of the severe Covid-19 patients who died did so because of typical Covid complications, such as clotting disorders or respiratory failure. The study suggests that severe Covid-19 may significantly damage long-term health and highlights the importance of preventing severe disease through vaccination.         

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Reality of long Covid

Covid-19 can cause severe symptoms and death for vulnerable people, particularly older patients and those with certain underlying conditions. You have likely also heard of long Covid, where symptoms such as fatigue and shortness of breath can linger for months after the infection has passed.

But how do Covid-19 patients fare in the long-term? Researchers have been tracking patients to understand the long-term impacts of the disease. “We conducted a previous study that showed that patients with severe Covid-19 who recovered were at significantly greater risk of being hospitalized in the subsequent six months,” explained Prof Arch Mainous of the University of Florida, lead author on the study. “This new study extended that to investigate mortality risk over the next 12 months.”

The researchers tracked electronic health records of 13,638 patients who underwent a PCR test for Covid-19 within the University of Florida health system, with 178 patients experiencing severe Covid-19, 246 mild or moderate Covid-19 and the rest testing negative. All patients included in the study recovered from the disease, and the researchers tracked their outcomes over the next 12 months.

Need to be more vigilant

The study found that patients who had recovered from severe Covid-19 had a significantly greater chance of dying over the next year, compared with the uninfected and mild or moderate Covid-19 patients. Some surprising trends emerged from the data, with severe Covid-19 patients aged under 65 demonstrating a 233% increased chance of dying, compared with the uninfected. This was larger than the increased chance of dying experienced by severe Covid-19 patients aged over 65, compared with the uninfected. As these deaths frequently occurred long after the initial infection had passed, they may never have been linked to Covid-19 by the patients’ families or doctors.

Moreover, most of the deaths that occurred in severe Covid-19 survivors were not linked with common complications from the disease, such as respiratory or cardiovascular issues. In fact, 80% of such deaths occurred for a wide variety of reasons that are not typically associated with Covid-19. This suggests that the patients had experienced an overall decline in their health that left them vulnerable to various ailments. Mild or moderate Covid-19 patients did not have a significantly increased mortality risk compared with the uninfected, highlighting the importance of reducing the chances of severe disease through vaccination.

“Since we now know that there is a substantial risk of dying from what would likely be considered to be an unrecognized complication of Covid-19, we need to be even more vigilant in decreasing severe episodes of Covid-19,” said Mainous. “Taking your chances and hoping for successful treatment in the hospital doesn’t convey the full picture of the impact of Covid-19. Our recommendation at this point is to use preventive measures, such as vaccination, to prevent severe episodes of Covid-19.” 

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