Reinfection of Covid-19 may increase the likelihood of new health problems

“Maybe if I asked me about reinfection a year and a half ago, I would tell you that there might be a patient here or there, but that’s really, really rare,” Al-Aly said. .. But that is no longer true.

“So, if I had a previous Covid infection and now I have a second infection, I asked a simple question if this really increases the risk. The simple answer is that.”

Aggregate the risk of reinfection

Al-Aly and his team have recorded the health records of more than 250,000 people who tested positive for Covid-19 at one time, and the records of 38,000 people who had more than one Covid-19 infection in their medical records. I compared. More than 5.3 million people with no record of Covid-19 infection were used as controls.

Of the re-infected individuals, 36,000 were infected twice with Covid-19, about 2,200 were infected with Covid-19 three times, and 246 were infected four times.

Common new diagnoses after reinfection included chest pain, arrhythmias, heart attacks, inflammation of the heart muscle or sac around the heart, heart failure, and blood clots. Common lung problems include shortness of breath, low blood oxygen, lung disease, and fluid buildup around the lungs, Al-Aly said.

The study also found that the risk of new health problems was highest during the reinfection of Covid-19, but persisted for at least 6 months. There was an increased risk, regardless of whether someone was vaccinated, and it was assessed in stages. In other words, the risk increased with each subsequent infection.

Al-Aly said that people do not expect it to happen when they infect Covid a second or third time.

“If you had Covid before, the idea is that your immune system is trained to recognize it and you’re ready to fight it, and if you get it, it’s less influential. It may not be, but it isn’t. It’s really true. “

Al-Aly said it doesn’t mean that no one has Covid and is doing well. There are many of them. Rather, his research shows that each infection poses a new risk, which increases over time.

He said that even if the risk of developing persistent health problems during the second infection is half that of the first infection, the risk of the problem is 50% higher than those who did not get Covid-19. rice field. Second time.

There are some important caveats to this study. Al-Aly says reinfection was more common among people who were at existing risk due to age and underlying health. This indicates that the reinfection may not be random. The health risks associated with reinfection may not be the same.

“People who are sick or have immune dysfunction are at increased risk of reinfection and can adversely affect their health after reinfection,” Al-Aly said.

He wasn’t interested in trying to isolate the pure effects of reinfection, but wanted to understand how repeated infections affect those who get them.

“The most relevant question in people’s lives is, if you are re-infected, does it increase your risk of acute complications and long Covids, and the answer is clearly yes and yes,” he said. Told.

This study is observational and means that the cause and effect cannot be identified.

Before Al-Aly was infected with Covid-19, researchers weighted the data to explain the effects of age, gender, drug use, and the person’s basic health, but researchers are still at these risks. Says he saw an increase in.

Covid-19 continues to be surprised

Experts who weren’t involved in the study say it’s compelling.

“Many people have the idea that if you survive the first infection, the second one will really be fine.” It shouldn’t really be a problem, “he said. Daniel Griffin, a clinical medicine instructor at Columbia University.

“The general wisdom is correct, reinfection is mild, don’t worry, there’s nothing to see here,” Griffin said of his study on the podcast “Virology of the Week.” But that’s not really backed up, he said.

This is not the way it is supposed to work. Even when the form of the virus changes, such as the flu, our immune system generally retains a memory of how to recognize and repel some of the virus. They may still make us sick, but the idea is that our previous immunity is there to implement some kind of defense and protect us from serious harm.

Coronaviruses, especially SARS-CoV-2 coronaviruses, continue to be hit.

“After a year, you can be infected twice with the same coronavirus. The second infection can be milder because the coronavirus is inherently capable of interfering with long-lasting lifelong immunity. Is not clear, “Griffin told CNN.

Griffin says he saw a bidirectional reinfection of Covid-19. Sometimes the second or third is milder for his patient, but sometimes it isn’t.

How is it compared to other respiratory infections?

In the early days of the pandemic, he said, three months had passed when people were infected with Covid and they were fairly well protected. But now there is no doubt that these reinfections occur more frequently due to the rapid changes in the virus. He says he has seen people infected four times in the last two years.

“We don’t see that much with the flu,” Griffin said.

Regarding what people should do now about this risk, Dr. Michael Osterholm, who heads the Center for Infectious Diseases Research Policy at the University of Minnesota, says Americans have really ended up in a pandemic. But that doesn’t mean that a pandemic will take place with us.

Osterholm said he had three close friends who recently went to the restaurant for the first time since the pandemic began. All of them were tested positive within 72 hours of the restaurant visit.

He says it’s a good time to wear an N95 mask in public places if you are at high risk of serious illness or just want to avoid getting sick.

“People don’t want to hear it, but it’s a reality. We’re seeing this resurrection, and the number of vaccine failures is increasing. Obviously, that’s a big concern,” he said.