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 children and teens who had COVID-19 were more likely to have stomach problems later. To do this, researchers compared electronic health record (EHR) data from over 1.5 million US children and teens who had COVID-19 with those who didn’t. The study found that kids who had COVID-19 were 25% more likely to have stomach issues, like belly pain, even after recovering from COVID-19. Specifically, 8.64% of kids who had COVID-19 experienced new stomach problems within a few months of having COVID-19 while only 6.85% of kids who didn’t have COVID-19 had stomach problems. This was true not only a few months after getting COVID-19 but also up to 2 years later. Doctors should be aware that kids who had COVID-19 might have more stomach problems. Knowing this can help doctors check for symptoms early and provide the right care.
In this RECOVER study, researchers aimed to improve a large national database on COVID-19 patients from many hospitals to better answer research questions about Long COVID. They noticed that the current database was missing the details needed to study Long COVID properly. To fix this, researchers created clear, step-by-step instructions to help hospitals add specific details from patients’ electronic health records (EHRs) to data they submitted to RECOVER. These extra details included notes on patient visits to Long COVID clinics, hospital stays, living situations, jobs, and if they needed extra oxygen while in the hospital. By June 2024, 29 hospitals had added this more complete information to the data they submitted to RECOVER. Having the hospitals submit data this way made it easier for researchers to compare patient information from different places. This study shows that using clear and standard ways to collect data are important for big research studies. It also shows that researchers sometimes need more details to study difficult research questions, like those about the long-term effects of COVID.
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.
Scientists updated a prior RECOVER study to explore Long COVID symptoms reported by participants in the RECOVER-Adult Observational Cohort Study. They compared symptoms in people who had COVID-19 to those who did not have COVID-19 to find the symptoms that were most different. The updated study included 13,647 participants, compared to 9,764 in the original, and added 8 new symptoms based on patient and community feedback. Symptoms that were most different between people with and without COVID-19 include post-exertional malaise, fatigue, brain fog, dizziness, palpitations, smell or taste change, thirst, chronic cough, chest pain, shortness of breath, and sleep apnea. In addition, this research update classifies Long COVID symptoms into 5 groups of symptoms called clusters. The previous study focused on 4 clusters. This study update is important because it highlights the wide range of symptoms experienced by people with Long COVID. Understanding these symptoms will help researchers study Long COVID and look for treatments.
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.
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.
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.
