Regardless of vaccination status, a study released on Thursday reveals that the risk of hospitalization, serious health problems, and death from COVID-19 increases considerably with reinfection.
Compared to patients who had COVID infection only once, patients who had it again had a risk of hospitalization and death that was more than twice as high.
The results were derived from data collected by the U.S. Department of Veterans Affairs (VA) on 443,588 patients with one SARS-CoV-2 infection, 40,947 patients with two or more illnesses, and 5.3 million uninfected people between March 1, 2020, and April 6, 2022. The majority of study participants were men.
"Reinfection with COVID-19 increases the risk of both acute outcomes and long COVID," Dr. Ziyad Al-Aly of Washington University School of Medicine in St. Louis. said "This was evident in unvaccinated, vaccinated, and boosted people."
"Even if one had prior infection and was vaccinated - meaning they had double immunity from prior infection plus vaccines - they are still susceptible to adverse outcomes upon reinfection," Al-Aly added.
Repeat infections were more than three times more likely to cause lung difficulties, three times more likely to cause cardiac problems, and 60% more likely to cause neurological disorders than people who had only been infected once. Researchers discovered that the increased risks were most prominent in the first month following reinfection but were still present six months later.
According to experts who were not engaged in the study, the VA population does not mirror the overall population.
According to John Moore, a professor of microbiology and immunology at Weill Cornell Medical College in New York, patients in VA health facilities are frequently older, sicker people, and often men, a group that would typically have more than normal health difficulties.
Even after taking into consideration variations in COVID-19 strains like Delta, Omicron, and BA.5, the researchers claimed that cumulative risks and burdens of recurring infection rose with the number of infections.
However, there appeared to be a "plateauing effect with multiple infections," with less of a surge in risk following the second infection, according to Dr. Celine Gounder, an infectious disease epidemiologist and an editor-at-large at Kaiser Health News.
"The good news there is that the better people are protected with immunity, likely the risk of developing some of the complications will be lower over time," she added.
Al-Aly nonetheless urged individuals to keep alert.
"We had started seeing a lot of patients coming to the clinic with an air of invincibility," he told Reuters. "They wondered, 'Does getting a reinfection really matter?' The answer is yes, it absolutely does."
