Research Summaries

This RECOVER study looked at how a child’s race or ethnicity might affect their chances of developing long-term health problems after getting COVID-19. Researchers studied data from 225,723 children and teens across 13 US hospitals and clinics from March 2020 to October 2022. They compared children who were diagnosed with COVID-19 or had a positive COVID-19 test to those who never tested positive. The study found that children with COVID-19 were more likely to develop many health problems weeks or months after getting COVID-19 than those who never had it. These problems included trouble breathing, feeling very tired (fatigue), and mental health problems.

Researchers also found that the chance of having these problems was different depending on a child's race or ethnicity. For example, Hispanic children with severe COVID-19 were more likely to have hair loss after getting sick than Non-Hispanic White children with severe cases. Non-Hispanic Black children with less severe COVID-19 were more likely to experience cognitive symptoms (related to thinking, memory, or concentration) than Non-Hispanic White children with less severe COVID-19. In children with less severe COVID-19, Asian American/Pacific Islander children were more likely to have more fever, chills, and respiratory symptoms (related to breathing) than Non-Hispanic White children. This study shows that long-term health problems in children and teens after COVID-19 may be different between racial and ethnic groups. This can help doctors better understand and treat Long COVID in people who are more likely to get it.

This RECOVER study looked at how well the Pfizer COVID-19 vaccine, called BNT162b2, protected children and teens from long-term health problems after having COVID-19, also known as Long COVID. Researchers studied the electronic health records (EHRs) from more than 385,000 children and adolescents across 13 hospitals and clinics during the Delta and Omicron waves. In the Delta wave, researchers studied the EHRs of 112,590 adolescents ages 12 to 20. Of these, 88,811 adolescents were vaccinated before getting COVID-19. In the Omicron wave, they studied the EHRs of 188,894 children ages 5 to 11 years old, and 84,735 adolescents ages 12 to 20. Of these, 101,277 children, and 37,724 adolescents were vaccinated before getting COVID-19. In the Delta period, the researchers found that vaccinated adolescents were 95% less likely to develop Long COVID. In the Omicron period, the vaccine lowered the risk of Long COVID by 60% in children and 75% in adolescents. The study also showed that the vaccine’s main benefit in preventing Long COVID in children and adolescents came from preventing them from getting COVID-19 in the first place.

This RECOVER study focused on a problem that happens when scientists study rare events. When scientists have very few cases of rare events to study, the usual ways of studying data can give misleading results. One way to fix this is to combine data from many hospitals or clinics so there are more cases to study. But, sharing detailed patient information raises concerns about privacy, so patient privacy must be protected when combining data from multiple healthcare centers.

In this study, RECOVER researchers created a new tool called ODAP-B, which combines information more accurately without sharing patient details. This is because it only needs a summary of patient data, not full health records. By using ODAP-B, researchers can better understand what increases the chance of a rare event happening while protecting patient privacy.

Metformin is a drug that many doctors prescribe as treatment for type 2 diabetes mellitus (T2DM). Past studies have found that taking metformin before and while having COVID-19 helps lower the chances of getting very sick with COVID-19. These studies also found that taking metformin can lower the chance of a person being sick many months after getting COVID-19, which is called Long COVID. In this study, RECOVER researchers were interested in understanding if people with diabetes who were on different medications got Long COVID or died. They looked at electronic health records (EHRs), or computer-based versions of patient health records, for 88,342 adults with T2DM. The study looked at 2 groups. The first group used metformin to control their diabetes, while the second group used other medications to control their diabetes. The researchers found that the chances of getting Long COVID or dying were a little bit lower in the group that took metformin compared to the group taking other medications. Since being on metformin may help only a little bit with Long COVID for adults with T2DM, people taking diabetes medications do not need to change their treatment plans unless told by their doctor.

This RECOVER study looked at how a child or young adult’s body weight, measured by body mass index (BMI), might impact their risk of developing Long COVID. Researchers studied medical records from over 172,000 children and young adults across 26 hospitals between March 2020 and May 2023. They found that children and young adults with obesity (a high BMI) were 25% more likely to have long-term health problems after getting COVID-19 than those with a healthy weight. The findings also show that children with severe obesity (a very high BMI) were about 42% more likely to experience these long-term problems. They also checked if these links were different for children and young adults, but did not find significant differences. This study highlights that the BMI of children and young adults before getting COVID-19 is an important factor in their risk for developing Long COVID.

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.