A new study from Washington
University School of Medicine in St. Louis and the Veterans Affairs St. Louis
Health Care system shows the health consequences of reinfection with
SARS-Cov-2. The researchers found that repeat SARS-CoV-2 infections contribute
significant additional risk of adverse health conditions in multiple organ
systems.

Such outcomes include
hospitalization; 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.

The findings are published
Nov. 10 in Nature Medicine.

Since the COVID-19 pandemic
began almost three years ago, scientists have learned that an initial infection
can lead to short- and long-term health risks affecting nearly every organ
system in the body. They’ve also determined that people can get COVID-19 a
second or a third time, despite acquiring natural antibodies after the first
infection and receiving vaccination and booster shots.

“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, MD, a clinical epidemiologist at the School of Medicine. “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.”

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.”

Limiting exposure to the
virus is especially important as the U.S. heads into the winter months, with
new variants emerging, mutating and already causing an upswing in infections in
some parts of the country, Al-Aly said. “People should do their best to prevent
repeat infections by masking, for example, getting all of their eligible
boosters, staying home when sick. Also, get a flu shot to prevent illness. We
really need to do our best to reduce the chance we will have a twin-demic of
both COVID-19 and the flu this winter season.”

For this study, the
researchers analyzed 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. Patients represented multiple ages,
races and sexes.

The researchers created a
controlled data set of 5.3 million people who did not test positive for
COVID-19 infection from March 1, 2020, through April 6, 2022. Using the same
time frame, the researchers also compiled a control group of more than 443,000
people who had tested positive for one COVID-19 infection, and another group of
nearly 41,000 people who had two or more documented infections. Of the latter
group, most people had two or three infections, with a small number having had four
infections and no one with five or more infections.

Statistical modeling was
used to examine the health risks of repeat COVID-19 infections within the first
30 days after contracting the virus and up to six months after.

The study accounted for
COVID-19 variants such as delta, omicron and BA.5. Negative outcomes occurred
among the unvaccinated as well as those who had received shots prior to
reinfection.

Overall, the researchers
found that people with COVID-19 reinfections were twice as likely to die and
three times more likely to be hospitalized than those with no reinfection.

Additionally, people with
repeat infections were 3½ 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.

“Our findings have broad
public health implications as they tell us that strategies to prevent or reduce
the risk of reinfection should be implemented,” Al-Aly said. “Going into the
winter season, people should be aware of the risks and practice vigilance to
reduce their risk of infection or reinfection with SARS-CoV-2.”

Reference:

Ziyad Al-Aly et al,Acute
and post-acute sequelae associated with SARS-CoV-2 reinfection, Nature Medicine, DOI 10.1038/s41591-022-02051-3

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