Discover what the latest science from the RECOVER Initiative means for our ability to understand, diagnose, prevent, and treat Long COVID.
This page contains descriptions of findings from RECOVER research studies. These descriptions use plain language and a format that is easy to understand.
If you want to learn more about the scientific discoveries described here, you can also browse and search the complete list of RECOVER Publications.
This RECOVER study looked at whether some children were more likely to have long-term breathing or brain/nerve problems after having COVID-19. Researchers studied the electronic health records (EHRs) of 771,725 pediatric patients under the age of 21 across the US. They found that children under 5 years of age and Hispanic White children had a higher chance of having breathing problems linked to Long COVID. This was also true if they lived in low-income areas or had other breathing problems before getting COVID-19. Children ages 12–17 years old and non-Hispanic White children were more likely to have brain and nerve problems related to Long COVID, especially if they already had other problems related to the brain and nerves. These findings show that race and ethnicity may affect how children experience Long COVID. Factors like where children live and how easy it is for them to get healthcare could play a role in these differences. This research shows why it’s important to understand these factors, so all children can get the care they need after having COVID-19.
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.
A RECOVER study looked at whether a person’s sex at birth affects their risk of developing Long COVID. To do this, researchers studied a large group of people enrolled in the RECOVER adult cohort. They found that females were more likely to have Long COVID symptoms than males. Among females, the risk of getting Long COVID changed based on age, pregnancy status while having COVID-19, and if they had gone through menopause. Researchers discovered that the risk of getting Long COVID was higher in females ages 40–54 years and females who had not gone through menopause. On the other hand, females who had already gone through menopause were not at a higher risk compared to males. More research is needed to understand why differences in sex at birth may put someone at higher risk of experiencing the long-term effects of COVID-19. Knowing this and understanding which hormones play a role in Long COVID risk could help researchers develop treatments and ways to prevent Long COVID.
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.
RECOVER researchers studied how COVID affects people over time. They wanted to know if parts of the SARS-CoV-2 virus (which causes COVID-19), called antigens, stay in people's blood long after a COVID infection. They also wanted to see if these antigens are linked to Long COVID. Long COVID is when a person has 1 or more symptoms that last for at least 3 months after getting COVID. First, the researchers took blood samples from adults who had COVID. These samples were taken a few days after getting sick and up to 14 months later. Then, they looked for 3 types of antigens that are usually in the blood after having COVID: the S1 subunit of the spike protein, the nucleocapsid protein, and the full-length spike protein. The full-length spike protein was the most common antigen found in adults who had COVID, especially in those who had blood taken between 4 and 7 months after getting COVID.
The study also looked at 34 common Long COVID symptoms, like trouble breathing, muscle pain, and brain fog. Many participants said that they had at least 1 Long COVID symptom for 1 month or more after getting sick. In the group with the most common kinds of symptoms, 2 out of 5 people had antigens in their blood. In the group without symptoms, about 1 out of 5 people had antigens in their blood. This study shows that the 3 antigens researchers found might be linked to Long COVID. People with symptoms were twice as likely to have these antigens in their blood for a long time. The results also show that parts of the SARS-CoV-2 virus can stay in the blood for up to 14 months after an infection. This is true for people who have long-term symptoms. But, it is also true in some people who do not have long-term symptoms.
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.
