Important update: Healthcare facilities

CDC has updated select ways to operate healthcare systems effectively in response to COVID-19 vaccination. Learn more

Find the latest information:
Recommendations for Fully Vaccinated People
COVID-19 Homepage

UPDATE

Given new evidence on the B.1.617.2 (Delta) variant, CDC has updated the guidance for fully vaccinated people. CDC recommends universal indoor masking for all teachers, staff, students, and visitors to K-12 schools, regardless of vaccination status. Children should return to full-time in-person learning in the fall with layered prevention strategies in place.

UPDATE

The White House announced that vaccines will be required for international travelers coming into the United States, with an effective date of November 8, 2021. For purposes of entry into the United States, vaccines accepted will include FDA approved or authorized and WHO Emergency Use Listing vaccines. More information is available here.

UPDATE

Travel requirements to enter the United States are changing, starting November 8, 2021. More information is available here.

CDC Science behind Long COVID

How CDC is using science to learn more about Long COVID

Updated Sept. 25, 2023

For the General Public: Long COVID (Post-COVID Conditions)

CDC is analyzing healthcare data, partnering with clinicians, and working with researchers to learn more about Long COVID.

Long COVID includes a wide range of new, returning, or ongoing health problems people can experience 4 or more weeks after being infected with SARS-CoV-2, the virus that causes COVID-19.

What CDC Is Doing to Learn about Long COVID

CDC and partners are working to learn more about Long COVID in a variety of populations and settings. These partnerships are essential for expanding the base of evidence needed for addressing Long COVID. CDC and its partners are working to:

Characterize and assess Long COVID to estimate both the risk of experiencing Long COVID and the numbers of people experiencing these conditions by demographic group.
Identify risk factors to better understand how to prevent Long COVID.
Identify groups disproportionately affected by Long COVID.
Assess the burden (health and financial costs) of Long COVID.
Identify successful interventions to prevent and lessen the effect of Long COVID. This research includes:
- Assessing if COVID-19 vaccinations and treatment reduce the occurrence of Long COVID, and
- Promoting equity in healthcare access and utilization for people with Long COVID.
Disseminate clinical guidance and other education materials for healthcare providers, patients, and the public to improve understanding of Long COVID.

Science at CDC

Scientific articles and manuscripts about COVID-19 and Long COVID

MMWR COVID-19 Reports CDC Scientific Publications on COVID-19

CDC and partners are collecting and analyzing information about Long COVID and health problems through several public health activities, including:

Prospective cohort studies that observe people over time,
Sentinel surveillance to collect information from select public health sources on cases of Long COVID,
Medical chart abstraction to understand the health and medical care of patients with Long COVID,
Analyses of electronic healthcare data and large patient databases,
State and national health surveys, and
Evaluation of models of care.

Inclusion of data and analyses of Long COVID by race/ethnicity, age, sex, and other factors are a CDC priority.

Related Research

Select examples of research on Long COVID conducted by CDC and partners

FindCOVID

Follows people infected with SARS-CoV-2 and their household members to measure initial clinical presentation, viral shedding, transmission, immune response, and ongoing symptoms from the time of infection up to 8 months.

Population: Children and adults

Partner: University of California, San Francisco (UCSF)

COVID-19 within American Indian Communities at High Risk in the Southwest U.S.

Followed people for up to 12 months who were infected with SARS-CoV-2 to assess the development and duration of symptoms, complications from infection, and immune response over time.

Population: Navajo and White Mountain Apache communities

Partners: Johns Hopkins University, Bloomberg School of Public Health, Center for American Indian Health

COVID: Research on COVID Long-Term Illness, Effects, and Risk Factors (COVID-RELIEF)

Tracks electronic health records of patients who test positive and negative for SARS-CoV-2 and documents symptoms and medical conditions for an average of 2 years after acute infection. A subgroup of patients who previously tested positive for SARS-CoV-2 provides self-reported data on health and biospecimens to investigate genetic and other risk factors for delayed recovery.

Population: Adults receiving care in a university health system

Partner: University of Washington, Seattle, WA

COVID-19: Understanding the Post-Viral Phase (COVID-UPP)

Assesses participants’ health over time using surveys and, for a subset of participants, using physical exams and medical tests to compare differences and similarities of the post-viral phase of SARS-CoV-2 infection with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Adults who tested positive for SARS-CoV-2 and continue to have symptoms more than 3 months after infection are compared with those who fully recovered.

Population: Adults, with a focus on persons who are Hispanic/Latino and who tested positive for SARS-CoV-2 and continue to have symptoms more than 3 months after infection

Partner: Nova Southeastern University, Fort Lauderdale, FL

Support for Patients With SARS-CoV-2 Infections Registry (INSPIRE)

Adults who test positive for SARS-CoV-2 and a comparison group of adults who test negative for SARS-CoV-2 are contacted every 3 months for up to 18 months. Participants complete detailed surveys, including information on social determinants of health, and provide linked electronic health information.

Population: Adults tested for SARS-CoV-2 infection

Partners: Rush University, Yale University, Jefferson Medical, University of Washington, UCLA, UCSF, UT Southwestern, UT Houston

COVID – Standardized Evaluation of Long-term Effects (COVID-SELECT)

Asks patients at risk of or who have Long COVID about their health through online questionnaires, with follow-up on their health one year later. Information will be used to identify and describe those who have long-term symptoms after having COVID-19 and whose results on routine medical tests and physical examination are normal.

Population: Adults from a demographically diverse population receiving care in a large, integrated health system in northern and central California

Partners: Public Health Foundation Enterprises, Inc.; California Emerging Infections Program; Kaiser Permanente Northern California, Oakland, CA

Multi-Site Study of Post-COVID Conditions (MPCC)

Collects and describes the health and medical care of patients at clinics designed for Long COVID care to help classify types of Long COVID health problems and care needed and highlights unmet needs for care in other medical settings.

Population: Adult patients receiving care in Long COVID clinics at participating medical centers through September 30, 2021

Partners: Rainmaker Strategic Solutions, LLC; University of Texas Southwestern Medical Center; Dallas, TX; Creighton University Medical Center, Omaha, NE; Mt. Sinai Health System, New York, NY

Post-COVID Conditions among Patients Seen in Outpatient Settings – American Family Cohort

Analyzes electronic health record data from COVID-19 patients seen at over 800 primary care and family medicine practices to assess frequency of new symptoms and conditions among patients with COVID-19 diagnosis compared with patients with other respiratory diagnoses. Study will assess Long COVID by race/ethnicity, age, sex, geography (urban/rural), and indices of social vulnerability.

Population: Children and adults

Partner: American Board of Family Medicine; Stanford University Center for Population Health Sciences

Post-COVID Conditions among Patients Seen in Outpatient and Inpatient Settings – PCORnet

Analyzes electronic health record data from COVID-19 patients seen in ambulatory, emergency department, and hospital settings in 40 U.S. healthcare systems to assess frequency of new symptoms and conditions among patients who tested positive for SARS-CoV-2 compared with patients who tested negative.

Population: Children and adults

Partner: PCORnet, the National Patient-Centered Clinical Research Network

Frequency of and Risk Factors for Post-COVID Conditions – Various Healthcare Data Sources

Analyzes several large healthcare data sources to provide estimates of new symptoms and conditions following COVID-19 diagnosis in outpatient and inpatient settings by patient demographic and clinical characteristics.

Population: Children and adults

Data Sources: HealthVerity, Premier Healthcare Database Special COVID-19 Release, Cerner Health eData Lab

National Health Interview Survey

Collects information about Long COVID symptoms through a cross-sectional household survey to estimate the national prevalence of Long COVID.

Population: Adults and children

Data Source: National Center for Health Statistics, CDC

Behavioral Risk Factor Surveillance System

Collects information about symptoms of Long COVID through a survey to produce state/territorial-level estimates of prevalence.

Population: Adults

Data Source: National Center for Chronic Disease Prevention and Health Promotion, CDC; participating state and territorial health departments

Multi-state Long Covid Survey

Surveyed adults who tested positive for SARS-CoV-2 for self-reported acute and Long COVID symptoms lasting 4 weeks or more to estimate prevalence of Long COVID and identify demographic and disease-specific risk factors for developing Long COVID.

Population: Adults who tested positive for SARS-CoV-2 in Maine, Wisconsin, New York, and New Jersey

Partners: State health departments

Long COVID and Fatiguing Illness Recovery Program (LC&FIRP)

Evaluates whether educational interventions for primary healthcare providers through a distance-learning platform improve health outcomes of patients with Long COVID and other complex chronic conditions with similar symptoms, such as myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and other illnesses that cause post-infectious fatigue.

Population: Adults who are uninsured, with lower incomes, and who are medically underserved

Partners: Family Health Centers of San Diego (FHCSD), San Diego, California; Project ECHO, Albuquerque, NM; University of Washington Post-COVID Clinic Rehabilitation and Recovery, Seattle, WA; University of Colorado, Denver, CO; ATA Health Strategies, Washington, DC

Tracking the Burden, Distribution, and Impact of Post COVID-19 Conditions in Diverse Populations for Children, Adolescents, and Adults (Track PCC)

TrackPCC is a multi-year sentinel surveillance project that will investigate the burden and impact of Long COVID in diverse populations within the United States. TrackPCC entails both passive and active surveillance and long-term follow-up of cohorts in collaboration with public health, academic, and healthcare partners.

As part of passive surveillance, TrackPCC investigators will collect information from patients who test positive for SARS-CoV-2 infection at four surveillance sites for up to 18 months using electronic health records to estimate incidence of symptoms and conditions occurring after SARS-CoV-2 infection. New cohorts of patients who tested positive for SARS-CoV-2 will be added every 3 months to the surveillance system. People who previously tested positive will be followed to identify those who develop Long COVID symptoms.

As part of active surveillance, TrackPCC investigators will survey a sample of patients who test positive for SARS-CoV-2 from the four surveillance sites for ongoing symptoms 3 months after infection, and then every 6 months for up to 18 months. This will provide estimates of the prevalence of symptoms that continue for more than 3 months after COVID-19 illness and provide information on symptom duration, severity of symptoms, impact on daily activities, and associated health disparities.

Population: Children and adults who test positive for SARS-CoV-2 infection

Partners: Abt Associates, Indiana University, Temple University, University of Arizona, and Comagine Health (Collaborative: Boise State University, Utah Health Information Network, and Bronx Regional Health Information Organization)

How can I Participate in Long COVID Research?

The National Institutes of Health (NIH) created the RECOVER Initiative, a research project that aims to understand how people recover from a SARS-CoV-2 infection and why some people do not fully recover and develop Long COVID or post-acute sequelae of SARS-CoV-2 (PASC). Anyone can participate in the RECOVER project, including those who have COVID-19 now, had COVID-19 before, or never had COVID-19. People of all races and ethnicities, genders, ages, and locations will be included in the research project to better understand how Long COVID affects people.

To learn more, including enrollment, visit the RECOVER web page.

Clinical Outreach and Communication Activity (COCA) Calls

The purpose of COCA continuing education opportunities is to increase clinicians’ knowledge of threats to the public’s health and provide information on clinical evaluation management strategies to address these threats. COCA continuing education is free. Learn about receiving continuing education (CE) credit for COCA calls.

Featured Webinars

September 20, 2023: Evaluating and Supporting Patients Presenting with Cardiovascular Symptoms Following COVID
June 15, 2023: Evaluating and Supporting Patients with Long COVID in Returning to Work
February 23, 2023: Evaluating and Supporting Children and Adolescents Presenting with Post-COVID Conditions
May 5, 2022: Evaluating and Supporting Patients Presenting with Cognitive Symptoms Following COVID

More COCA Calls/Webinars

CDC Publications

CDC is publishing the results of studies aimed at better understanding Long COVID and how best to support people experiencing Long COVID symptoms and related health problems.

Select CDC publications on Post-COVID Conditions and related topics:

Prospective Cohort Studies

O’Laughlin KN, Thompson M, Hota B, Gottlieb M, Plumb ID, Chang AM, Wisk LE, Hall AJ, Wang RC, Spatz ES, Stephens KA, Huebinger RM, McDonald SA, Venkatesh A, Gentile N, Slovis BH, Hill M, Saydah S, Idris AH, Rodriguez R, Krumholz HM, Elmore JG, Weinstein RA, Nichol G; INSPIRE Investigators. Study protocol for the Innovative Support for Patients with SARS-COV-2 Infections Registry (INSPIRE): A longitudinal study of the medium and long-term sequelae of SARS-CoV-2 infection. PLoS One. 2022 Mar 3;17(3).
Han JH, Womack KN, Tenforde MW, Files DC, Gibbs KW, Shapiro NI, Prekker ME, Erickson HL, Steingrub JS, Qadir N, Khan A, Hough CL, Johnson NJ, Ely EW, Rice TW, Casey JD, Lindsell CJ, Gong MN, Srinivasan V, Lewis NM, Patel MM, Self WH; Influenza and Other Viruses in the Acutely Ill (IVY) Network. Associations between persistent symptoms after mild COVID-19 and long-term health status, quality of life, and psychological distress. Influenza Other Respir Viruses. 2022 Mar 28.
Michael Gottlieb, Erica S Spatz, Huihui Yu, Lauren E Wisk, Joann G Elmore, Nicole L Gentile, Mandy Hill, Ryan M Huebinger, Ahamed H Idris, Efrat R Kean, Katherine Koo, Shu-Xia Li, Samuel McDonald, Juan Carlos C Montoy, Graham Nichol, Kelli N O’Laughlin, Ian D Plumb, Kristin L Rising, Michelle Santangelo, Sharon Saydah, Ralph C Wang, Arjun Venkatesh, Kari A Stephens, Robert A Weinstein, INSPIRE Group. Long COVID Clinical Phenotypes up to 6 Months After Infection Identified by Latent Class Analysis of Self-Reported Symptoms
Michael Gottlieb, Ralph C Wang, Huihui Yu, Erica S Spatz, Juan Carlos C Montoy, Robert M Rodriguez, Anna Marie Chang, Joann G Elmore, Paavali A Hannikainen, Mandy Hill, Ryan M Huebinger, Ahamed H Idris, Zhenqiu Lin, Katherine Koo, Samuel McDonald, Kelli N O’Laughlin, Ian D Plumb, Michelle Santangelo, Sharon Saydah, Michael Willis, Lauren E Wisk, Arjun Venkatesh, Kari A Stephens, Robert A Weinstein, for the Innovative Support for Patients with SARS-CoV-2 Infections Registry (INSPIRE) Group. Severe Fatigue and Persistent Symptoms at 3 Months Following Severe Acute Respiratory Syndrome Coronavirus 2 Infections During the Pre-Delta, Delta, and Omicron Time Periods: A Multicenter Prospective Cohort Study
Erica S Spatz, Michael Gottlieb, Lauren E Wisk, Jill Anderson, Anna Marie Chang, Nicole L Gentile, Mandy J Hill, Ryan M Huebinger, Ahamed H Idris, Jeremiah Kinsman, Katherine Koo, Shu-Xia Li, Samuel McDonald, Ian D Plumb, Robert M Rodriguez, Sharon Saydah, Benjamin Slovis, Kari A Stephens, Elizabeth R Unger, Ralph C Wang, Huihui Yu, Bala Hota, Joann G Elmore, Robert A Weinstein, Arjun Venkatesh. Three-Month Symptom Profiles Among Symptomatic Adults With Positive and Negative Severe Acute Respiratory Syndrome Coronavirus 2 Tests: A Prospective Cohort Study From the INSPIRE Group
Lauren E. Wisk, PhD1,2; Michael A. Gottlieb, MD3; Erica S. Spatz, MD, MHS4,5; et al. Association of Initial SARS-CoV-2 Test Positivity With Patient-Reported Well-being 3 Months After a Symptomatic Illness

Analysis of Electronic Healthcare Data

Hernandez-Romieu AC, Leung S, Mbanya A, Jackson BR, Cope JR, Bushman D, Dixon M, Brown J, McLeod T, Saydah S, Datta D, Koplan K, Lobelo F. Health Care Utilization and Clinical Characteristics of Nonhospitalized Adults in an Integrated Health Care System 28-180 Days After COVID-19 Diagnosis – Georgia, May 2020-March 2021. MMWR Morb Mortal Wkly Rep. 2021 Apr 30;70(17):644-650.
Hernandez-Romieu AC, Carton TW, Saydah S, Azziz-Baumgartner E, Boehmer TK, Garret NY, Bailey LC, Cowell LG, Draper C, Mayer KH, Nagavedu K, Puro JE, Rasmussen SA, Trick WE, Wanga V, Chevinsky JR, Jackson BR, Goodman AB, Cope JR, Gundlapalli AV, Block JP. Prevalence of Select New Symptoms and Conditions Among Persons Aged Younger Than 20 Years and 20 Years or Older at 31 to 150 Days After Testing Positive or Negative for SARS-CoV-2. JAMA Netw Open. 2022 Feb 1;5(2).
Barrett CE, Koyama AK, Alvarez P, Chow W, Lundeen EA, Perrine CG, Pavkov ME, Rolka DB, Wiltz JL, Bull-Otterson L, Gray S, Boehmer TK, Gundlapalli AV, Siegel DA, Kompaniyets L, Goodman AB, Mahon BE, Tauxe RV, Remley K, Saydah S. Risk for Newly Diagnosed Diabetes >30 Days After SARS-CoV-2 Infection Among Persons Aged <18 Years – United States, March 1, 2020-June 28, 2021. MMWR Morb Mortal Wkly Rep. 2022 Jan 14;71(2):59-65.
Chevinsky JR, Tao G, Lavery AM, Kukielka EA, Click ES, Malec D, Kompaniyets L, Bruce BB, Yusuf H, Goodman AB, Dixon MG, Nakao JH, Datta SD, MacKenzie WR, Kadri SS, Saydah S, Giovanni JE, Gundlapalli AV. Late Conditions Diagnosed 1-4 Months Following an Initial Coronavirus Disease 2019 (COVID-19) Encounter: A Matched-Cohort Study Using Inpatient and Outpatient Administrative Data-United States, 1 March-30 June 2020. Clin Infect Dis. 2021 Jul 15;73(Suppl 1):S5-S16.
Lyudmyla Kompaniyets, PhD; Lara Bull-Otterson, PhD; Tegan K. Boehmer, PhD; Sarah Baca; Pablo Alvarez, MPH; Kai Hong, PhD; Joy Hsu, MD; Aaron M. Harris, MD; Adi V. Gundlapalli, MD, PhD; Sharon Saydah, PhD. CDC Morbidity and Mortality Weekly (MMWR), Aug. 5, 2022. Post–COVID-19 Symptoms and Conditions Among Children and Adolescents — United States, March 1, 2020–January 31, 2022
Lara Bull-Otterson, PhD; Sarah Baca; Sharon Saydah, PhD; Tegan K. Boehmer, PhD; Stacey Adjei, MPH; Simone Gray, PhD; Aaron M. Harris, MD. CDC MMWR, May 27, 2022. Post–COVID Conditions Among Adult COVID-19 Survivors Aged 18–64 and ≥65 Years — United States, March 2020–November 2021

Health Surveys

Wanga V, Chevinsky JR, Dimitrov LV, Gerdes ME, Whitfield GP, Bonacci RA, Nji MAM, Hernandez-Romieu AC, Rogers-Brown JS, McLeod T, Rushmore J, Lutfy C, Bushman D, Koumans E, Saydah S, Goodman AB, Coleman King SM, Jackson BR, Cope JR. Long-Term Symptoms Among Adults Tested for SARS-CoV-2 – United States, January 2020-April 2021. MMWR Morb Mortal Wkly Rep. 2021 Sep 10;70(36):1235-1241.
Nicole D. Ford, PhD; Douglas Slaughter, MPH; Deja Edwards, MPH; Alexandra Dalton, PhD; Cria Perrine, PhD; Anjel Vahratian, PhD; Sharon Saydah, PhD. CDC Morbidity and Mortality Weekly (MMWR), Aug. 11, 2023. Long COVID and Significant Activity Limitation Among Adults, by Age — United States, June 1–13, 2022, to June 7–19, 2023

Electronic Medical Chart Abstraction

Rogers-Brown JS, Wanga V, Okoro C, Brozowsky D, Evans A, Hopwood D, Cope JR, Jackson BR, Bushman D, Hernandez-Romieu AC, Bonacci RA, McLeod T, Chevinsky JR, Goodman AB, Dixon MG, Lutfy C, Rushmore J, Koumans E, Morris SB, Thompson W. Outcomes Among Patients Referred to Outpatient Rehabilitation Clinics After COVID-19 diagnosis – United States, January 2020-March 2021. MMWR Morb Mortal Wkly Rep. 2021 Jul 9;70(27):967-971. Erratum in: MMWR Morb Mortal Wkly Rep. 2021 Aug 20;70(33):1126. PMID: 34237048; PMCID: PMC8312758.

Commentary

Saydah SH, Brooks JT, Jackson BR. Surveillance for Post-COVID Conditions Is Necessary: Addressing the Challenges with Multiple Approaches. J Gen Intern Med. 2022 Feb 15:1–3.
Datta SD, Talwar A, Lee JT. A Proposed Framework and Timeline of the Spectrum of Disease Due to SARS-CoV-2 Infection: Illness Beyond Acute Infection and Public Health Implications. JAMA. 2020 Dec 8;324(22):2251-2252.