Repeated Covid infections increase risk of serious health problems, study finds

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People who have had Covid more than once are two or three times more likely to have a range of serious health problems than those who have only had it once, the first major study on the subject said Thursday.

Multiple infections have surged as the pandemic rumbles on and the virus mutates into new strains, but the long-term health effects of reinfection have not been clear.

The US researchers said their new study published in the Nature Medicine journal was the first to look at how reinfection increases the risk of health problems from acute cases as well as long Covid.

The researchers analysed the anonymous medical records of 5.8 million people in the US Department of Veterans Affairs' national healthcare database.

More than 443,000 had tested positive for Covid at least once between March 1, 2020 and April this year.

Nearly 41,000 of that group had Covid more than once. Over 93 percent had a total of two infections, while six percent had three and nearly one percent had four.

The other 5.3 million never contracted Covid.

When the researchers compared the health outcomes of the different groups, they found that "people who got reinfected have an increased risk of all sorts of adverse health problems," Ziyad Al-Aly, an epidemiologist at Washington University in St Louis and the study's senior author, told AFP.

People with repeat infections were twice as likely to die prematurely and three times more likely to be hospitalised with illness than those who had not been reinfected, the study found.


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