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COVID Impacts

Detailed information and resources on the long-term health consequences of COVID-19 infection and the broad social impacts of the COVID-19 pandemic

Post-Covid Conditions by Severity

Clinical Spectrum of COVID-19 Infection

According to the NIH COVID-19 Treatment Guidelines, the clinical spectrum of infection for adults with confirmed COVID-19 acute infection includes presymptomatic/asymptomatic infection, mild illness, moderate illness, severe illness, and critical illness.

  • Asymptomatic or presymptomatic infection Individuals who test positive for SARS-CoV-2 using a virologic test (i.e., a nucleic acid amplification test [NAAT] or an antigen test) but have no symptoms consistent with COVID-19.
  • Mild illness Individuals who have any of the various signs and symptoms of COVID-19 (e.g., fever, cough, sore throat, malaise, headache, muscle pain, nausea, vomiting, diarrhea, loss of taste and smell) but do not have shortness of breath, dyspnea, or abnormal chest imaging.
  • Moderate illness Individuals who show evidence of lower respiratory disease during clinical assessment or imaging and who have an oxygen saturation measured by pulse oximetry (SpO2) ≥94% on room air at sea level.
  • Severe illness Individuals who have SpO2 <94% on room air at sea level, a ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (PaO2/FiO2) <300 mm Hg, a respiratory rate >30 breaths/min, or lung infiltrates >50%.
  • Critical illness Individuals who have respiratory failure, septic shock, and/or multiple organ dysfunction.

Prevalence of Long COVID

A large number of studies have shown that between 10-20% of people with acute COVID-19 infections go on to develop post-acute conditions (aka "Long COVID"). And that each infection increases individual risk of developing Long COVID. Although post-COVID conditions are more common in patients who were hospitalized with acute COVID-19 infection, it is clear that even patients who had mild or asymptomatic acute infections still can develop a wide range of debilitating symptoms, including neurocognitive, respiratory, and cardiovascular complications.

While the rates of Long Covid symptoms appears to be lower for patients with reported Omicron infections (compared to earlier variants), the risks posed by repeated infections could be catastrophic. It is also unclear what future variants might cause, or the possibility of developing complications in the months and years following an acute COVID-19 infection.

A January 2023 study published in BMJ found that "patients who were diagnosed with mild COVID-19 were up to 4.6 times more likely than uninfected patients to have some symptoms associated with post–COVID-19 condition (PCC) for 6 to 12 months." Symptoms associated with post-COVID conditions were more significant for altered sense of smell and/or taste, cognitive issues, shortness of breath, weakness, and heart palpitations. There was also a lower but still significant risk for dizziness. Risks were more apparent from 30 to 180 days after infection compared to 180 to 360 days, suggesting that many symptoms subsided in these patients within a year after infection.

Post-COVID Conditions in Children

The signs and symptoms of SARS-CoV-2 infection in symptomatic children may be similar to those in adults; however, a greater proportion of children may be asymptomatic or have only mild illness when compared with adults. The most common signs and symptoms of COVID-19 in hospitalized children are fever, nausea/vomiting, cough, shortness of breath, and upper respiratory symptoms.

The signs and symptoms of COVID-19 may overlap significantly with those of influenza and other respiratory and enteric viral infections. Critical disease, including respiratory failure, acute respiratory distress syndrome, and, less commonly, shock, may occur in children with COVID-19. The overall incidence of SARS-CoV-2 infection and, by extension, COVID-19-related hospitalizations among children has increased substantially with the the emergence of the Omicron variant and its descendants.

Long Covid Kids

The reported clinical manifestations and duration of post-COVID conditions in children are highly variable. Not all pediatric studies included controls without SARS-CoV-2 infection, which makes determining the true incidence a challenge. However, the incidence of post-COVID symptoms appears to increase with age.

The most common symptoms reported include persistent fatigue, headache, shortness of breath, sleep disturbances, and altered sense of smell.