What doesn't kill you might actually make you weaker if it's COVID-19, a new study has found.
Researchers in the US who tracked hundreds of patients for 12 months, and found those who'd been ill enough to require hospital care were more than twice as likely to die in the months after they recovered than those who never caught the virus.
The effect was strongest in people under 65, who were 233 percent more likely to die in the year after their hospitalisation for any reason, many of which GPs probably didn't realise could be linked back to their infection.
"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," the researchers said on Thursday, following the publication of the research in journal Frontiers in Medicine.
"In fact, 80 percent 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."
It's not clear yet how many people who recover from COVID-19 go on to suffer 'long COVID' - symptoms lasting for months after the initial infection is cleared. Some studies have estimated as many as half of those who contract the virus have at least one symptom of long COVID, even after mild infections, and it's not clear yet whether vaccines reduce its likelihood or severity.
The good news out of the latest study is that those who only had a mild infection didn't have a corresponding increase in risk of post-infection death, "highlighting the importance of reducing the chances of severe disease through vaccination".
"Taking your chances and hoping for successful treatment in the hospital doesn't convey the full picture of the impact of COVID-19," said Arch Mainous of the University of Florida, study lead author.
"Our recommendation at this point is to use preventive measures, such as vaccination, to prevent severe episodes of COVID-19."
