A team of US researchers has revealed that repeated Covid infections contribute significant additional risk of adverse health conditions in multiple organ systems, putting people at a high risk of organ failure and death.
The study from Washington University School of Medicine in St. Louis and the Veterans Affairs St. Louis Health Care system in the US, published in the journal Nature Medicine, documented the health consequences of Covid reinfection.
Such outcomes include hospitalisation, disorders affecting the lungs, heart, brain, and the body's blood, musculoskeletal and gastrointestinal systems, and even death.Reinfection also contributes to diabetes, kidney disease and mental health issues, they wrote.
"During the past few months, there's been an air of invincibility among people who have had Covid-19 or their vaccinations and boosters, and especially among people who have had an infection and also received vaccines; some people started to referring to these individuals as having a sort of superimmunity to the virus," said senior author Ziyad Al-Aly, a clinical epidemiologist at Washington University.
Without ambiguity, "our research showed that getting an infection a second, third or fourth time contributes to additional health risks in the acute phase, meaning the first 30 days after infection, and in the months beyond, meaning the long Covid phase," Al-Aly added.
Additionally, the study indicated that the risk seems to increase with each infection."This means that even if you've had two Covid-19 infections, it's better to avoid a third," Al-Aly said. "And if you've had three infections, it's best to avoid the fourth."
For this study, the researchers analysed about 5.8 million de-identified medical records in a database maintained by the U.S. Department of Veterans Affairs, the nation's largest integrated health-care system. The study accounted for variants such as delta, omicron and BA.5.
Overall, the researchers found that people with Covid-19 reinfections were twice as likely to die and three times more likely to be hospitalised than those with no reinfection.Additionally, people with repeat infections were three-and-a-half times more likely to develop lung problems, three times more likely to suffer heart conditions and 1.6 times more likely to experience brain conditions than patients who had been infected with the virus once.
"People should do their best to prevent repeat infections by masking, for example, getting all of their eligible boosters, staying home when sick and getting a flu shot to prevent illness," said the researchers.