All the research
Long Covid Learning collects research from scientists worldwide and summarizes the findings to make takeaways more accessible to those outside the research community. Study summaries can be shared as links or images in messages and social media.
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Lung damage even without symptoms
Magnetic resonance images showed lung damage in children and adolescents after Covid infection in both those reporting Long Covid symptoms and those who do not. These children had both lower functional breathing volume and blood supply volume to the lungs compared with the never-infected healthy controls, which still persisted one year after infection.
Magnetic resonance images showed lung damage in children and adolescents after Covid infection in both those reporting Long Covid symptoms and those who do not.
These children had both lower functional breathing volume and blood supply volume to the lungs compared with the never-infected healthy controls, which still persisted one year after infection.
Source: Pulmonary Dysfunction after Pediatric COVID-19 | Radiology (rsna.org)
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Persistent systemic infection for months
In people who died of Covid, the virus was found in various tissues throughout the body, including the brain, as late as 230 days following the symptom onset of an acute infection. In some patients, the virus can cause systemic infection and persist in the body for months. Among the other affected organs and tissues are the heart and blood vessels, lungs and the respiratory system, muscles, skin, thyroid, esophagus, spleen, appendix, adrenal glands, ovaries, testes, and womb.
In people who died of Covid, the virus was found in various tissues throughout the body, including the brain, as late as 230 days following the symptom onset of an acute infection.
In some patients, the virus can cause systemic infection and persist in the body for months. Among the other affected organs and tissues are the heart and blood vessels, lungs and the respiratory system, muscles, skin, thyroid, esophagus, spleen, appendix, adrenal glands, ovaries, testes, and womb.
Source: SARS-CoV-2 infection and persistence in the human body and brain at autopsy | Nature
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Long-term heart and lung issues
Adults under 55 years old hospitalized for Covid continue to suffer from long-term heart and lung issues. Two months after being released from the hospital, about 8% of patients studied had pulmonary hypertension (high blood pressure of the lungs), while 10% of them had a heart defect related to pulmonary hypertension. Including those who had borderline conditions inconsistent with their age, at least 1 in 5 were found to have abnormalities of either the heart or lungs.
Adults under 55 years old hospitalized for Covid continue to suffer from long-term heart and lung issues.
Two months after being released from the hospital, about 8% of patients studied had pulmonary hypertension (high blood pressure of the lungs), while 10% of them had a heart defect related to pulmonary hypertension. Including those who had borderline conditions inconsistent with their age, at least 1 in 5 were found to have abnormalities of either the heart or lungs.
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Virus in stool 10 months later
SARS-CoV-2 particles are found in the stool of 13% of patients even 7 months after mild to moderate Covid. This "fecal shedding" can continue even 10 months after the initial infection and is associated with gastrointestinal symptoms like abdominal pain, nausea, and vomiting, suggesting prolonged infection of the gastrointestinal tract.
SARS-CoV-2 particles are found in the stool of 13% of patients even 7 months after mild to moderate Covid.
This "fecal shedding" can continue even 10 months after the initial infection and is associated with gastrointestinal symptoms like abdominal pain, nausea, and vomiting, suggesting prolonged infection of the gastrointestinal tract.
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Risk remains after vaccines
This study selected a predominantly healthy, younger adult population and used a limited survey-based methodology. For this population it reported that receiving two doses of a Covid vaccine at least two weeks before infection lowered the risk of Long Covid symptoms 12 weeks later by 41%. The risk of those symptoms being severe enough to limit daily activity dropped by 37%. While this study shows that significant risk of Long Covid remains after vaccination, additional studies are needed to confirm how much vaccines reduce this risk.
⚠️ This study selected a predominantly healthy, younger adult population and used a limited survey-based methodology.
For this population it reported that receiving two doses of a Covid vaccine at least two weeks before infection lowered the risk of Long Covid symptoms 12 weeks later by 41%.
The risk of those symptoms being severe enough to limit daily activity dropped by 37%. While this study shows that significant risk of Long Covid remains after vaccination, additional studies are needed to confirm how much vaccines reduce this risk.
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Damaged immune system
Even patients never hospitalized for Covid have dramatically reduced T cells counts (a key part of the body's immune system), and the surviving T cells and appear less capable of fighting disease due to cellular exhaustion. Those whose T cell counts drop very low after Covid infection may require urgent help even if their initial infection was milder, as this damage to the immune system was found to put patients at higher risk of deteriorating health or even death.
Even patients never hospitalized for Covid have dramatically reduced T cells counts (a key part of the body's immune system), and the surviving T cells and appear less capable of fighting disease due to cellular exhaustion.
Those whose T cell counts drop very low after Covid infection may require urgent help even if their initial infection was milder, as this damage to the immune system was found to put patients at higher risk of deteriorating health or even death.
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Insulin resistance and diabetes
Even those without a prior history of diabetes demonstrate abnormal insulin resistance and glycemic abnormalities 2 months after infection. Even a mild Covid infection is associated with 28% higher risk of developing type 2 diabetes in the year after initial infection. This suggests the need for diabetes screening even after mild Covid cases.
Even those without a prior history of diabetes demonstrate abnormal insulin resistance and glycemic abnormalities 2 months after infection.
Even a mild Covid infection is associated with 28% higher risk of developing type 2 diabetes in the year after initial infection.
This suggests the need for diabetes screening even after mild Covid cases.
Sources: Incidence of newly diagnosed diabetes after Covid-19 | SpringerLink and Acute and long-term disruption of glycometabolic control after SARS-CoV-2 infection | Nature Metabolism
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24 million affected in the U.S.
The U.S. CDC estimates that of the 24 million adults in the U.S. currently suffering from Long Covid, more than 80% are having some trouble carrying out daily activities. 1 in 4 say they are experiencing significant limitations in their activity due to Long Covid. Nearly 30% of all adults previously infected with Covid reported having Long Covid symptoms at some point.
The U.S. CDC estimates that of the 24 million adults in the U.S. currently suffering from Long Covid, more than 80% are having some trouble carrying out daily activities.
1 in 4 say they are experiencing significant limitations in their activity due to Long Covid. Nearly 30% of all adults previously infected with Covid reported having Long Covid symptoms at some point.
Source: Long COVID - Household Pulse Survey - COVID-19 (cdc.gov)
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48% affected 6-18 months later
48% of those in a population-level study reported persistent symptoms, impaired daily activities, and reduced health-related quality of life in the 6-18 months after Covid infection across sociodemographic factors and pre-existing health conditions. 1 in 20 had not recovered at all and 1 in 9 had worsening symptoms over the course of the study. Being vaccinated before infection reduced the risk of 7 of the 26 symptoms evaluated by 25-40%.
48% of those in a population-level study reported persistent symptoms, impaired daily activities, and reduced health-related quality of life in the 6-18 months after Covid infection across sociodemographic factors and pre-existing health conditions.
1 in 20 had not recovered at all and 1 in 9 had worsening symptoms over the course of the study. Being vaccinated before infection reduced the risk of 7 of the 26 symptoms evaluated by 25-40%.
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77% affected 12 months later
12 months after mostly mild Covid infections, only 23% were symptom-free. Patients reported significantly reduced physical and mental quality of life from symptoms like reduced exercise capacity (56%), fatigue (53%), breathing problems (38%), and trouble concentrating (40%) and finding words (32%). Researchers also found signs of the immune system attacking healthy cells.
12 months after mostly mild Covid infections, only 23% were symptom-free.
Patients reported significantly reduced physical and mental quality of life from symptoms like reduced exercise capacity (56%), fatigue (53%), breathing problems (38%), and trouble concentrating (40%) and finding words (32%). Researchers also found signs of the immune system attacking healthy cells.
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53% affected 6-12 months later
53.1% of those with a confirmed Covid infection reported symptoms like mental and physical exhaustion, sleep problems, and cognitive problems 6-12 months later, as compared to 11.5% of those without a confirmed infection. 1 in 14 patients was newly diagnosed with depression, anxiety, chronic fatigue symptom (CFS), fibromyalgia, or PTSD within the first year after a confirmed Covid infection.
53.1% of those with a confirmed Covid infection reported symptoms like mental and physical exhaustion, sleep problems, and cognitive problems 6-12 months later, as compared to 11.5% of those without a confirmed infection.
1 in 14 patients was newly diagnosed with depression, anxiety, chronic fatigue symptom (CFS), fibromyalgia, or PTSD within the first year after a confirmed Covid infection.
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Damage to multiple organs
59% of those with Long Covid — most of whom were not hospitalized at the time of infection — were found to have suffered organ damage (spanning heart, lungs, kidneys, liver, pancreas, and spleen) in a longitudinal and prospective study. Organ impairment and symptoms like fatigue, breathlessness and cognitive dysfunction continued to have high prevalence after 12 months, with significant impact on quality-of-life.
59% of those with Long Covid — most of whom were not hospitalized at the time of infection — were found to have suffered organ damage (spanning heart, lungs, kidneys, liver, pancreas, and spleen) in a longitudinal and prospective study.
Organ impairment and symptoms like fatigue, breathlessness and cognitive dysfunction continued to have high prevalence after 12 months, with significant impact on quality-of-life.
Source: Multi-organ impairment and Long COVID: a 1-year prospective, longitudinal cohort study | medRxiv
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1 in 4 kids and teens affected
25% of kids and teens with symptomatic Covid later reported Long Covid symptoms, per an analysis of 21 studies. While the studies used a variety of methodologies (yielding a wide range of estimates), the most common symptoms consistently included mood changes (e.g., sadness, tension, anger, depression, and anxiety), fatigue, sleep disorders, headache, respiratory symptoms, congestion, and cognition problems such as difficulty learning and concentrating, confusion, and memory loss. Relative to control groups, those infected were also at higher risk of difficulty breathing, loss of smell and taste, and persistent fever.
25% of kids and teens with symptomatic Covid later reported Long Covid symptoms, per an analysis of 21 studies.
While the studies used a variety of methodologies (yielding a wide range of estimates), the most common symptoms consistently included mood changes (e.g., sadness, tension, anger, depression, and anxiety), fatigue, sleep disorders, headache, respiratory symptoms, congestion, and cognition problems such as difficulty learning and concentrating, confusion, and memory loss. Relative to control groups, those infected were also at higher risk of difficulty breathing, loss of smell and taste, and persistent fever.
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Damaged immune system
Those reporting Long Covid symptoms showed measurable abnormalities in their immune system that can persist at least 8 months. Patients with Long Covid had evidence of ongoing inflammation including highly activated immune cells, lack of inactivated T and B cells, and elevated presence of cytokines that are signatures of ongoing active immune response. This provides further evidence of physical damage from Long Covid.
Those reporting Long Covid symptoms showed measurable abnormalities in their immune system that can persist at least 8 months.
Patients with Long Covid had evidence of ongoing inflammation including highly activated immune cells, lack of inactivated T and B cells, and elevated presence of cytokines that are signatures of ongoing active immune response. This provides further evidence of physical damage from Long Covid.
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Millions unable to work
Of the 16 million working-age Americans currently suffering from Long Covid, 2-4 million are out of work because of their illness, according to analysis by the Brookings Institution based on U.S. Census Bureau data. The annual cost of those lost wages is $170 billion a year, not including reduced productivity from people working while sick, health care costs, or stopping work to care for family.
Of the 16 million working-age Americans currently suffering from Long Covid, 2-4 million are out of work because of their illness, according to analysis by the Brookings Institution based on U.S. Census Bureau data.
The annual cost of those lost wages is $170 billion a year, not including reduced productivity from people working while sick, health care costs, or stopping work to care for family.
Source: New data shows long Covid is keeping as many as 4 million people out of work (brookings.edu)
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Symptoms can take 6-9 months
Long Covid symptoms including fatigue, difficulty breathing, difficulty concentrating, and trouble sleeping occur in a large fraction of patients and last over 12 months after the initial infection. The most common symptoms occur in 20-45% of patients. Findings from the 250,000 patients studied suggest that some symptoms become more common over time, first appearing 6-9 months after infection. While there were considerable differences in how the 63 studies analyzed were conducted, Long Covid is now recognized as a complex systemic disease with substantial morbidity.
Long Covid symptoms including fatigue, difficulty breathing, difficulty concentrating, and trouble sleeping occur in a large fraction of patients and last over 12 months after the initial infection. The most common symptoms occur in 20-45% of patients.
Findings from the 250,000 patients studied suggest that some symptoms become more common over time, first appearing 6-9 months after infection. While there were considerable differences in how the 63 studies analyzed were conducted, Long Covid is now recognized as a complex systemic disease with substantial morbidity.
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Risk remains after vaccines
Vaccines offer only limited protection against a few Long Covid consequences, reducing risk by less than 30%. The chances of most consequences are reduced only marginally — or not at all. Risks of all Long Covid symptoms together, as well as new cognitive symptoms, heart problems, kidney disease, liver disease, sleep disorders, abnormal breathing, diabetes, obesity, chest pain, joint pain, hypertension, abdominal pain, anxiety, depression, headache, and other symptoms did not differ between those with and without prior vaccination.
Vaccines offer only limited protection against a few Long Covid consequences, reducing risk by less than 30%. The chances of most consequences are reduced only marginally — or not at all.
Risks of all Long Covid symptoms together, as well as new cognitive symptoms, heart problems, kidney disease, liver disease, sleep disorders, abnormal breathing, diabetes, obesity, chest pain, joint pain, hypertension, abdominal pain, anxiety, depression, headache, and other symptoms did not differ between those with and without prior vaccination.
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Life-long neurological issues
Covid infection increases the risk of neurological disorders by 42% regardless of age, race, sex, and prior health, according to a study of 11.6 million people with mostly mild initial infections. This study of neurologic outcomes after 12 months suggests that 7 people in every 100 Covid infections will suffer potentially life-long consequences, with even higher risks of memory, cognitive, sensory, and other disorders in younger adults.
Covid infection increases the risk of neurological disorders by 42% regardless of age, race, sex, and prior health, according to a study of 11.6 million people with mostly mild initial infections.
This study of neurologic outcomes after 12 months suggests that 7 people in every 100 Covid infections will suffer potentially life-long consequences, with even higher risks of memory, cognitive, sensory, and other disorders in younger adults.
Source: Long-term neurologic outcomes of COVID-19 | Nature Medicine
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Difficulty and stigma at work
Half (49.5%) of patients with mild Covid still suffered from health problems a month later, including 29% reporting trouble with their performance at work. 43% of those surveyed experienced stigma and discrimination, raising the question of whether it's common for those suffering from Long Covid to hide their illness from colleagues and friends.
Half (49.5%) of patients with mild Covid still suffered from health problems a month later, including 29% reporting trouble with their performance at work.
43% of those surveyed experienced stigma and discrimination, raising the question of whether it's common for those suffering from Long Covid to hide their illness from colleagues and friends.
Source: Long COVID occurrence in COVID-19 survivors | Scientific Reports (nature.com)
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Accelerated biological aging
Covid adds years or decades to "biological age," such that the DNA of a 25yo can look like that of a 50yo after even a mild infection. Multiple measures of age were studied including methylation and telomere shortening. Telomeres are protective caps on DNA strands that are useful as cellular biomarkers for aging and have been linked to aging related diseases such as cancer, heart disease, and more. These were significantly shorter for all age groups after Covid. The average biological aging effect due to a Covid infection was 10 years, with the greatest changes in younger patients.
Covid adds years or decades to "biological age," such that the DNA of a 25yo can look like that of a 50yo after even a mild infection.
Multiple measures of age were studied including methylation and telomere shortening. Telomeres are protective caps on DNA strands that are useful as cellular biomarkers for aging and have been linked to aging related diseases such as cancer, heart disease, and more. These were significantly shorter for all age groups after Covid. The average biological aging effect due to a Covid infection was 10 years, with the greatest changes in younger patients.
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