Discover what the latest science from the RECOVER Initiative means for our ability to understand, treat, and prevent 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.
Researchers wanted to see if patients who had difficulty breathing while sleeping (Obstructive Sleep Apnea; OSA) were at higher risk for developing Long COVID compared to people without OSA. By comparing the electronic health record (EHR) data of COVID positive patients, researchers looked at the risk of developing Long COVID in patients with and without a previous diagnosis of OSA.
Researchers found that adults with a previous diagnosis of OSA had an increased chance of developing Long COVID when compared to patients that did not have a previous diagnosis of OSA.
Long COVID patients, caregivers, and community members contribute to all parts of RECOVER, including scientific research. These chosen members of the community are known as RECOVER Representatives. This paper, written by a team of RECOVER Representatives and researchers, talks about why they chose to work together and how their partnership has improved the study. They summarize some of the impacts of Long COVID and highlight the roles that patient advocacy can play in research. They also discuss what progress has been made so far in studying Long COVID and what challenges lie ahead. The authors state that the result of Representatives working together with researchers on study design, ways to include patients, and sharing community concerns has set a new example for the design of future biomedical research studies.
To understand Long COVID, researchers must be able to figure out which patients have it. Our understanding of Long COVID is evolving and it has been difficult to know who had Long COVID, especially in children. We need a reliable method to identify who might have Long COVID using existing health data.
The purpose of this study was to create and test a computer program, called an algorithm, to find out which children have Long COVID based on their electronic health records (EHRs). EHRs (digital medical charts that have health data like doctor visits, lab results, and other health history) are an important source of data for research studies on Long COVID. The algorithm looks at EHRs to find patterns in the diagnoses, prescribed medications, procedures, and lab tests children received after having COVID-19. These patterns can be described as a phenotype, or a set of measured or visible traits, that can tell us who had Long COVID.
The algorithm correctly identified 67% of the patients who had a Long COVID diagnosis from the EHRs. Among the patients who the algorithm said had Long COVID, 91% had a Long COVID diagnosis. Overall, the algorithm was correct in identifying whether a patient had a Long COVID diagnosis 99% of the time. This means the phenotype can be used to recognize which children have Long COVID in EHR data for future studies, or to screen patients to participate in clinical trials.
RECOVER researchers used data from the RECOVER observational cohort study in adults ages 18 and over. They compared symptoms reported in surveys by participants who did and did not have COVID.
Researchers found 37 symptoms that participants who had COVID reported more often after having COVID compared to participants who never had COVID. 12 of these symptoms could identify participants with Long COVID, including feeling tired and unwell after activity, feeling weak and tired (fatigue), and brain fog. A definition of Long COVID based on symptoms is important for future research, including to find treatments.
To find another way to know if children had COVID, researchers compared health records of 2 groups of children: children who only had a positive antibody test and children who had a positive PCR test. A positive antibody test means a child had COVID in the past, had the COVID vaccine, or both. A positive PCR test means a child currently has COVID. Researchers used data from children’s hospitals in the National Pediatric Learning Health System (PEDSnet) network.
Antibody tests found 2,714 children who had COVID and didn’t have a positive PCR test or COVID vaccine. If researchers used only PCR tests, they wouldn’t have known these children had COVID. Knowing if children had COVID is the first step to know their risk of Long COVID and if symptoms could be related to Long COVID.
RECOVER researchers wanted to understand whether being vaccinated before having COVID lowered the chance of developing Long COVID. They used electronic health records (EHR) to study the effect of vaccination using EHR for two groups of people who had COVID. One group was based on clinic data and represented more than 47,000 people. In this group, 695 were diagnosed with Long COVID in clinics and more than 26,000 were fully vaccinated. The other group represented almost 200,000 individuals who had COVID. The researchers used a computer program to estimate who might have Long COVID in this group based on their medical and symptom information. In this group, more than 86,000 people represented were fully vaccinated. The researchers made sure that the people in the vaccinated and unvaccinated groups were as similar to each other as possible in terms of the same sex, age, race, and medical history.
To test whether vaccination lowered the chance of developing Long COVID, they made comparisons within each group. They used several different definitions of Long COVID and several different statistical tests to figure out whether vaccination status affected Long COVID. For both of the study groups and for all definitions of Long COVID and each statistical test in the analysis, the researchers got the same answer: people who were vaccinated before having COVID were less likely to develop Long COVID.
This paper summarizes some work of the RECOVER Mechanistic Pathways Task Force. This group does research on what happens in body systems when people have Long COVID. In this study, the authors reviewed existing research about why and for how long SARS-CoV-2, the virus that causes COVID-19, stays in the body. The authors also reviewed research on whether SARS-CoV-2 might become dormant (inactive) and then reactivate later as part of its natural lifecycle. They discuss whether the amount of time the virus stays in the body, also known as the “persistence” of the virus, could be related to whether or not people develop Long COVID. They also describe what is known so far about this topic, what we still need to find out, and the types of research studies that may help answer these questions.
People who had COVID-19 may develop Long COVID, which is when someone may experience various health issues after having COVID. Many of these problems are due to a strong reaction to the SARS-CoV-2 virus by the immune system (the body’s defense system that fights infections). This reaction can happen a long time after the virus is no longer in the body.
A healthy immune system can tell the difference between our body’s healthy cells and the harmful ones that can make us sick. However, an overactive immune system can make mistakes and cause harm because it may attack healthy organs and tissues. The immune system response to diseases like COVID is complex and different for each person.
It is important to understand how the immune system works after having COVID for many different people, and this may require large, long-term studies. This paper reviews researchers’ current knowledge and the gaps in their understanding about the immune response after a COVID infection and how that may lead to both short-term and long-term problems.
RECOVER researchers explored Multisystem Inflammatory Syndrome in Children (MIS-C), a Long COVID symptom where there is inflammation (swelling) of multiple organ systems. Researchers looked to see if MIS-C can be identified and managed in the home (outpatient) instead of in the hospital (inpatient).
An organ system is a collection of organs in your body dedicated to maintaining necessary functions. For example, your heart, arteries, and veins make up the Cardiovascular System--the system responsible for maintaining blood flow and delivering oxygen throughout the body.
Researchers were able to identify that in some patients, their MIS-C symptoms were mild enough to be treated at home and not require hospitalization. These results raise awareness that MIS-C can present in milder forms with the option to treat it at home if directed by a physician.
