Study: Repeat COVID Infection Is Riskier than First

A new study has found that the risk of death, hospitalization and serious health issues from COVID-19 increases with reinfection regardless of vaccination.

The study examined U.S. Department of Veterans Affairs data collected from March 1, 2020 through April 6, 2022. It included information on 443,588 patients with one SARS-CoV-2 infection, 40,947 with two or more infections, and 5.3 million who were not infected. Most of the study subjects were male.

"Reinfection with COVID-19 increases the risk of both acute outcomes and long COVID," said Dr. Ziyad Al-Aly of Washington University School of Medicine in St. Louis. He added that this was clear "in unvaccinated, vaccinated and boosted people."

Reinfected patients had a doubled risk of death and a tripled risk of hospitalization compared with individuals infected only once. The patients also had increased risks for a number of other health problems, the study, reported in Nature Medicine, found. The problems affected the lungs, heart, blood, kidneys, bones and muscles. Reinfection also increased the risk of mental health, brain and nerve disorders.

"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," said Al-Aly. He was the lead writer of the study.

Susceptible means easily affected or harmed by something.

People with repeat infections were three times more likely to develop lung problems, three times more likely to suffer heart conditions and 60 percent more likely to have brain or nerve disorders, the study found. The risks were highest in the first month after reinfection but were still clear six months later.

The total risks of repeat infection increased with the number of infections, even after examining differences in COVID-19 variants such as Delta, Omicron and BA.5, the researchers said.

"We had started seeing a lot of patients coming to the clinic with an air of invincibility," Al-Aly told Reuters. "They wondered, 'Does getting a reinfection really matter?' The answer is yes, it absolutely does."

He added that ahead of a season that often involves travel and indoor gatherings, people should be aware that reinfection is serious and should take steps to avoid getting infected.

Al-Aly explained that researchers are not suggesting serious measures, "but maybe if you're going on a plane, wear a mask." Or, if a person is in a food store, "consider that the person near you may have a weak immune system, and if you wear a mask you might help to protect them," he said.

I'm John Russell.

Nancy Lapid reported on this story for Reuters. John Russell adapted it for VOA Learning English.

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acute – adj. very serious or dangerous : requiring serious attention or action

prior – adj. existing or happening before the present time

adverse – adj. bad or unfavorable : not good

invincibility – n. impossible to defeat or overcome

immune – adj. relating to the way your body fights disease