After only a few months of the COVID-19 pandemic, scientists and clinicians knew that the virus could cause myriad health problems in various organs throughout the body. While a SARS-CoV-2 infection begins as in the nose, airways, and lungs, it can go on to disrupt the function of blood vessels, interfere with senses of taste and smell, and cause gastrointestinal distress, for some examples. There can also be a host of long-term effects that are so common in patients who have recovered from an initial COVID-19 infection, there is a term form it - long COVID, or post acute coronavirus syndrome (discussed in the video below).
While people can develop immunity to SARS-CoV-2 from an infection, a vaccine shot, or a combination of those things, the virus has continued to mutate, which it is still doing, and it can infect people multiple times. Scientists have now found that repeat SARS-CoV-2 infections significantly increases the likelihood of other health problems, which can affect the brain, heart, lungs, gastrointestinal system, mucoskeletal system, and mortality. Repeat infections also increase the risk of kidney disease, mental health issues, and diabetes. The findings have been reported in Nature 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," said senior study author Ziyad Al-Aly, MD, a clinical epidemiologist at the School of Medicine.
The risks appear to increase with every infection. So if you have already had COVID-19, two or even three times, it's still best to avoid getting it again, said Al-Aly, who added that people who have been vaccinated, been sick with COVID-19, or both, should not feel invincible. Prevention continues to be very important.
If you can be in well-ventilated areas, try to do so, and take precautions. Anyone who is eligible should wear a mask, get boosted, and get a flu shot, said Al-Aly. This is particularly important as the winter season arrives, and new variants keep emerging.
The study authors assessed about 5.8 million medical records from a U.S. Department of Veterans Affairs database, with multiple races, ages, and sexes represented. Of those, about 5.3 million did not get COVID-19 between March 2020 and April 2022, so they served as controls. Another 443,000 people did get one COVID-19 infection during that time, while almost 41,000 had two documented infections, or more. Most of them had been sick two or three times, while a small number of people had four infections (no one had five documented cases, according to the database).
Taking several factors into account, including vaccination status and the variant causing the infection, the researchers found that people who had COVID-19 reinfections were twice as likely to die and three times as likely to be hospitalized with a subsequent COVID-19 case compared to people who had not been reinfected. Repeat infections also made people 3.5 times more likely to develop problems in their lungs, three times as likely to have heart problems, and 1.6 times more likely to have brain disorders compared to people who only got COVID-19 once.
One thing that is unclear is how researchers might be able to account for very mild or asymptomatic cases of COVID-19 that might not have been diagnosed or documented. Unfortunately, a lack of routine testing in the United States has made data on those mild cases impossible to ascertain.
Sources: Washington University in St. Louis, Nature Medicine