Research Summaries

In this RECOVER study, researchers wanted to find out which health conditions were common in people with long-term effects of COVID-19, known as Long COVID. They looked at the medical records of over 14 million patients who had and did not have COVID-19 using a method called topic modeling. Topic modeling is a method to find patterns in groups of documents. Researchers used topic modeling to look at lists of health problems that millions of patients faced over time, including before and after they had COVID-19. This allowed them to find the conditions that were more common in people with Long COVID. Researchers found that health problems related to the lungs, heart, brain, and immune system were more common in people with Long COVID compared to those who didn’t have Long COVID or had not had COVID-19. Common problems included chronic fatigue (feeling tired all the time), headaches, anxiety, and heart issues. They also found that some problems were more common in people of a certain age or sex (whether they are male or female). The study shows that Long COVID can affect many parts of the body and highlights how health problems can differ between groups. It also shows that age and sex can affect the chance of getting certain health conditions after COVID-19.

RECOVER researchers know that there is a lot of important information about COVID-19 and Long COVID in electronic health records (EHRs), especially in the notes that doctors write during care. The researchers used a computer tool called Natural Language Processing (NLP) to find signs and symptoms of different conditions. However, NLP doesn’t always work well, especially with new health problems like COVID-19 or Long COVID, which are always changing. To improve this, researchers created a new NLP system that could collect detailed information about Long COVID signs and symptoms from EHRs. After testing the system at other medical sites, they found it worked well across different locations. The study showed that the new NLP system could successfully find the information they were looking for about COVID-19 and Long COVID in EHRs. The NLP is now available to other researchers and is being used to collect information that can support additional studies on COVID-19 and Long COVID.

This RECOVER study looks at a medicine called nirmatrelvir/ritonavir, which is used to treat COVID-19 in teens and adults who are more likely to be hospitalized from COVID-19. Researchers wanted to understand why doctors might give this medicine to teens ages 12 to 17. They reviewed electronic health records (EHRs) from January 2022 to August 2023 to find which teens got this medicine after testing positive for COVID-19. Out of almost 21,000 teens with COVID-19, only 408 got the medicine within 5 days of diagnosis. The study found that teens with long-term health problems were 2.5 times more likely to get the medicine. Those with comorbidities (more than 1 ongoing health problem) were more likely to receive it. But most teens with 1 or more health problems did not receive this medication. This could be a reason why many teens with COVID-19 need to be hospitalized. The study also found that Hispanic or Latino kids were less likely to get the medicine compared to non-Hispanic, white kids. This study shows that kids with chronic health issues are more likely to get nirmatrelvir/ritonavir, but not many kids are getting this medicine overall.

This RECOVER study looks at how often people get COVID-19 more than once and if they develop Long COVID afterward. The study also looks at whether getting COVID-19 multiple times, also called a reinfection, is worse than the first time getting COVID-19. RECOVER researchers identified a reinfection when a person had a positive COVID-19 test at least 60 days after getting COVID-19 for the first time. They studied the health records of over 3 million patients in different ways to understand COVID-19 reinfections. By studying a large number of patients, the researchers were able to learn key details about COVID-19 reinfections. They found that about 6.9% of people got COVID-19 more than once. Most reinfections happened when the Omicron variant was spreading. Researchers found that Long COVID was more common in people who had COVID-19 for the first time compared to those who were reinfected. This finding suggests that protecting yourself from getting COVID-19 is the best way to prevent Long COVID. People who had a moderate or severe case of COVID-19 the first time were also more likely to get very sick again when they were reinfected. These people were often older and at higher risk of death.

Some people develop new conditions or symptoms after having COVID-19, called Long COVID. This can lead to ongoing health problems. Researchers still don’t fully understand why some people get Long COVID while others do not. In this RECOVER study, researchers wanted to learn what increases someone’s risk of developing Long COVID after getting COVID-19. Researchers studied the electronic health records of 2.1 million people from New York and Florida who either had or had not had COVID-19 between March 2020 and November 2021. Using this data, they created a new computational model (a computer program that imitates how something works in real life) to help identify the things that Long COVID patients had in common. The researchers looked at whether these shared factors increased their risk of developing Long COVID. The model found that the people who were more likely to develop Long COVID if they had severe COVID-19 the first time they got the virus, were underweight, or had other health problems, like cancer or liver disease. The results also show that computational models can help identify people who have a higher chance of developing different symptoms and types of Long COVID. This information is important because it can be used to help researchers find new ways to prevent, diagnose, and treat Long COVID.

Little is known about Long COVID in pregnant women. This study looked at whether getting COVID-19 while pregnant might increase the chances of getting Long COVID. Researchers from the RECOVER Patient-Centered Clinical Research Network (PCORnet) checked health records from 19 health systems across the US. They studied women ages 18–49 years old who had a test showing that they had COVID-19 between March 2020 and February 2022, and looked at 83,915 women who were not pregnant and 5,397 who were. Women who got COVID-19 while pregnant were less likely to get Long COVID than those who weren’t pregnant. Pregnant women with COVID-19 were more likely to develop certain conditions related to Long COVID, like an abnormal heartbeat. But they had a lower risk of getting other conditions, like malaise (feeling unwell). Overall, pregnant women with COVID-19 had a lower chance of getting Long COVID in the 30 to 180 days after they first got sick.

The virus that causes COVID-19 can change over time, creating new virus types called variants. This study explored if problems related to Long COVID were different in people who got different variants of COVID-19. Researchers looked at medical records from 2 databases in New York and Florida. They compared people who had the original type of COVID-19 with those who had a variant called Delta, which was one of the main variants in 2021. The researchers found that some Long COVID conditions were more common in the people who had Delta. For example, some people who got the Delta variant developed clots in the blood vessels in their lungs. People who had Delta were also more likely to have stomach symptoms than people who got the original type of COVID-19. Based on these findings, the researchers concluded that Long COVID symptoms can be different depending on which variant of COVID-19 someone had.

Doctors keep patient information in computer files called electronic health records (EHRs). RECOVER researchers can use these records to learn more about Long COVID, which is when someone feels sick for a long time after having COVID-19. But studying these records is not easy. It can be hard to get certain information from EHRs, when things that might explain why some people get Long COVID happen at different times. It can also be hard to put information from many hospitals together in one place and can cost a lot of money. In this study, RECOVER researchers made a new tool called ODACoR, which stands for “one-shot distributed algorithms for competing risks model.” This tool was used to look at the EHRs of 6.5 million kids and teens from 8 children’s hospitals. Researchers found that ODACoR was able to find information about things that could make children and teens more likely to get Long COVID. ODACoR could also combine information from different hospitals, which did not always work with old ways of studying health information. This tool gave the same results as if all the hospitals had shared all their information in one place, which is hard to do. This study is important because it can help doctors study other kinds of health problems using information from many hospitals.

Research shows that the COVID-19 vaccine lowers the chance of children getting sick from COVID-19. But it is not clear whether the COVID-19 vaccine protects against Long COVID. RECOVER researchers did a study to look at how well vaccines work in protecting children, ages 5–17, against Long COVID. They studied data from a group of more than 1 million children. The vaccine was 42% effective in lowering the chance of getting Long COVID in kids ages 5–11 and 50% effective for kids ages 12–17. The vaccine works best against Long COVID within the first 6 months of getting it. After 6 months, it does not work as well, so getting the vaccine every year is important to prevent Long COVID. These results show that the COVID-19 vaccine can help children 5 years and older to keep from getting very sick. While this study helps scientists understand how vaccines can protect against COVID-19, they still need to do more research to understand how they protect against Long COVID.