Long COVID, also known as Post-Acute Sequelae of SARS-CoV-2 infection (PASC), refers to health issues that can persist or reappear following an initial COVID-19 infection. These problems are considered Long COVID when experienced four or more weeks after the first onset of infection. The condition includes a wide spectrum of symptoms, some similar to acute COVID-19, while others are new. These effects can impact multiple organ systems and vary in presentation and duration.
Overall Prevalence Rates and Data
The prevalence of Long COVID varies across studies due to differences in methodologies, populations surveyed, and definitions. According to a 2023 CDC report based on 2022 data, about 6.9% of U.S. adults reported ever having Long COVID, with 3.4% reporting current symptoms. A more recent 2023 CDC report indicated that 6.4% of noninstitutionalized U.S. adults experienced Long COVID, with nearly 20% reporting significant daily activity limitations.
Global estimates from the World Health Organization (WHO) suggest that about 6 in 100 people who contract COVID-19 develop post-COVID-19 condition. These figures largely derive from infections occurring earlier in the pandemic. While more recent research indicates a reduction in the likelihood of developing Long COVID, such data are primarily from high-income countries.
Demographic Factors Influencing Prevalence
Demographic characteristics play a role in who is more likely to experience Long COVID. Data from the 2022 National Health Interview Survey show distinct patterns across different age groups. Adults aged 35–49 years had the highest reported rates of ever having Long COVID, at 8.9%, and currently having Long COVID, at 4.7%. In contrast, adults aged 65 and older reported the lowest rates, with 4.1% ever experiencing Long COVID and 2.3% currently affected. This suggests that while Long COVID can affect individuals of all ages, it is most frequently reported among working-age adults.
Women consistently show a higher prevalence of Long COVID compared to men. In 2022, 8.5% of women reported ever having Long COVID, compared to 5.2% of men. Similarly, 4.4% of women reported currently having Long COVID, while 2.3% of men did. This disparity highlights a significant finding in the epidemiology of Long COVID, indicating that biological or social factors may contribute to this gender difference.
Role of Initial Infection and Pre-existing Conditions
The severity of the initial COVID-19 illness significantly influences the likelihood of developing Long COVID. Individuals who experienced severe acute infections, particularly those requiring hospitalization or intensive care, face a higher risk of persistent symptoms. For example, one study found that Long COVID was diagnosed in 1% of non-hospitalized patients, 6% of hospitalized patients, and 32% of patients treated in the intensive care unit. Even mild initial infections can lead to Long COVID, but the risk increases with greater acute illness severity.
Certain pre-existing health conditions, or comorbidities, also heighten an individual’s susceptibility to Long COVID. People with chronic illnesses such as cardiovascular diseases, diabetes, and autoimmune conditions are at increased risk. Studies have identified several conditions statistically associated with an increased risk for Long COVID, including:
Asthma
Chronic constipation
Reflux
Rheumatoid arthritis
Seasonal allergies
Depression/anxiety
The presence of multiple comorbidities can further exacerbate this risk, suggesting a complex interplay between a person’s underlying health status and vulnerability to long-term post-viral effects.
Impact of Vaccination and Viral Variants
Vaccination against COVID-19 plays a role in reducing the risk of developing Long COVID. Studies indicate that being vaccinated before contracting SARS-CoV-2 lowers the likelihood of experiencing long-term symptoms. Research has shown that COVID-19 vaccines can reduce the risk of Long COVID by an estimated 40% to 50%. This protective effect is partly attributed to vaccines reducing the severity of acute infections.
Viral variants have also influenced the prevalence of Long COVID over time. Research suggests that the risk of Long COVID was lower with the Omicron variant compared to earlier variants like Delta. An analysis found that 4.5% of individuals infected during the Omicron period reported Long COVID symptoms, compared to 10.8% of those infected during the Delta period. Despite the reduced per-infection risk with Omicron, its higher transmissibility meant that the overall number of people experiencing Long COVID could still increase due to the sheer volume of infections.