You are leaving Medscape Education
Cancel Continue
Log in to save activities Your saved activities will show here so that you can easily access them whenever you're ready. Log in here CME & Education Log in to keep track of your credits.


How Effective Are COVID-19 Vaccines in Preventing Long COVID?

  • Authors: WebMD Health News Author: Carolyn Crist; CME Author: Charles P. Vega, MD
  • CME / ABIM MOC / CE Released: 4/1/2022
  • Valid for credit through: 4/1/2023
Start Activity

  • Credits Available

    Physicians - maximum of 0.25 AMA PRA Category 1 Credit(s)™

    ABIM Diplomates - maximum of 0.25 ABIM MOC points

    Nurses - 0.25 ANCC Contact Hour(s) (0 contact hours are in the area of pharmacology)

    Pharmacists - 0.25 Knowledge-based ACPE (0.025 CEUs)

    Physician Assistant - 0.25 AAPA hour(s) of Category I credit

    IPCE - 0.25 Interprofessional Continuing Education (IPCE) credit

    You Are Eligible For

    • Letter of Completion
    • ABIM MOC points

Target Audience and Goal Statement

This activity is intended for primary care physicians, infectious disease specialists, internal medicine clinicians, nurses, physician assistants, pharmacists, and other members of the healthcare team who care for patients at risk of COVID-19.

The goal of this activity is that members of the healthcare team will be able to understand whether COVID-19 vaccination is protective against long COVID.

Upon completion of this activity, participants will:

  • Analyze the transmissibility of SARS-CoV-2 variant Omicron BA.2
  • Evaluate the efficacy of COVID-19 vaccination against long COVID
  • Outline implications for the healthcare team


Medscape, LLC requires every individual in a position to control educational content to disclose all financial relationships with ineligible companies that have occurred within the past 24 months. Ineligible companies are organizations whose primary business is producing, marketing, selling, re-selling, or distributing healthcare products used by or on patients.

All relevant financial relationships for anyone with the ability to control the content of this educational activity are listed below and have been mitigated according to Medscape policies. Others involved in the planning of this activity have no relevant financial relationships.

WebMD Health News Author

  • Carolyn Crist


    Disclosure: Carolyn Crist has disclosed no relevant financial relationships.

CME Author

  • Charles P. Vega, MD

    Health Sciences Clinical Professor of Family Medicine
    University of California, Irvine School of Medicine


    Disclosure: Charles P. Vega, MD, has disclosed the following relevant financial relationships:
    Served as an advisor or consultant for: GlaxoSmithKline; Johnson & Johnson Pharmaceutical Research & Development, L.L.C.

Editor/Compliance Reviewer

  • Yaisanet Oyola, MD

    Associate Director, Accreditation and Compliance, Medscape, LLC


    Disclosure: Yaisanet Oyola, MD, has no relevant financial relationships.

Compliance Reviewer

  • Esther Nyarko, PharmD

    Director, Accreditation and Compliance
    Medscape, LLC


    Disclosure: Esther Nyarko, PharmD, has disclosed no relevant financial relationships.

PA Planner

  • Jennifer Hakkarainen, PA-C

    Medical Education Director, Medscape, LLC


    Disclosure: Jennifer Hakkarainen, PA-C, has disclosed no relevant financial relationships.

Peer Reviewer

This activity has been peer reviewed and the reviewer has disclosed no relevant financial relationships.

Accreditation Statements

In support of improving patient care, Medscape, LLC is jointly accredited by the Accreditation Council for Continuing Medical Education (ACCME), the Accreditation Council for Pharmacy Education (ACPE), and the American Nurses Credentialing Center (ANCC), to provide continuing education for the healthcare team.

This activity was planned by and for the healthcare team, and learners will receive 0.25 Interprofessional Continuing Education (IPCE) credit for learning and change.

    For Physicians

  • Medscape, LLC designates this enduring material for a maximum of 0.25 AMA PRA Category 1 Credit(s)™ . Physicians should claim only the credit commensurate with the extent of their participation in the activity.

    Successful completion of this CME activity, which includes participation in the evaluation component, enables the participant to earn up to 0.25 MOC points in the American Board of Internal Medicine's (ABIM) Maintenance of Certification (MOC) program. Participants will earn MOC points equivalent to the amount of CME credits claimed for the activity. It is the CME activity provider's responsibility to submit participant completion information to ACCME for the purpose of granting ABIM MOC credit.

    Contact This Provider

    For Nurses

  • Awarded 0.25 contact hour(s) of continuing nursing education for RNs and APNs; none of these credits is in the area of pharmacology.

    Contact This Provider

    For Pharmacists

  • Medscape, LLC designates this continuing education activity for 0.25 contact hour(s) (0.025 CEUs) (Universal Activity Number JA0007105-0000-22-077-H01-P).

    Contact This Provider

  • For Physician Assistants

    Medscape, LLC has been authorized by the American Academy of PAs (AAPA) to award AAPA Category 1 CME credit for activities planned in accordance with AAPA CME Criteria. This activity is designated for 0.25 AAPA Category 1 CME credits. Approval is valid until 4/1/2023. PAs should only claim credit commensurate with the extent of their participation.

For questions regarding the content of this activity, contact the accredited provider for this CME/CE activity noted above. For technical assistance, contact [email protected]

Instructions for Participation and Credit

There are no fees for participating in or receiving credit for this online educational activity. For information on applicability and acceptance of continuing education credit for this activity, please consult your professional licensing board.

This activity is designed to be completed within the time designated on the title page; physicians should claim only those credits that reflect the time actually spent in the activity. To successfully earn credit, participants must complete the activity online during the valid credit period that is noted on the title page. To receive AMA PRA Category 1 Credit™, you must receive a minimum score of 75% on the post-test.

Follow these steps to earn CME/CE credit*:

  1. Read the target audience, learning objectives, and author disclosures.
  2. Study the educational content online or printed out.
  3. Online, choose the best answer to each test question. To receive a certificate, you must receive a passing score as designated at the top of the test. We encourage you to complete the Activity Evaluation to provide feedback for future programming.

You may now view or print the certificate from your CME/CE Tracker. You may print the certificate but you cannot alter it. Credits will be tallied in your CME/CE Tracker and archived for 6 years; at any point within this time period you can print out the tally as well as the certificates from the CME/CE Tracker.

*The credit that you receive is based on your user profile.


How Effective Are COVID-19 Vaccines in Preventing Long COVID?

Authors: WebMD Health News Author: Carolyn Crist; CME Author: Charles P. Vega, MDFaculty and Disclosures

CME / ABIM MOC / CE Released: 4/1/2022

Valid for credit through: 4/1/2023


Note: The information on the coronavirus outbreak is continually evolving. The content within this activity serves as a historical reference to the information that was available at the time of this publication. We continue to add to the collection of activities on this subject as new information becomes available. It is the policy of Medscape Education to avoid the mention of brand names or specific manufacturers in accredited educational activities. However, manufacturer names related to COVID-19 vaccines may be provided in this activity to promote clarity. The use of manufacturer names should not be viewed as an endorsement by Medscape of any specific product or manufacturer.

Clinical Context

The world is still reeling from the most recent surge of COVID-19 related to the Omicron variant. Nonetheless, the global incidence rate of COVID-19 has declined substantially during February. At the same time, there is concern that the Omicron BA.2 subvariant will promote the next global surge in infections. A preprint study by Lyngse and colleagues[1] assessed the ability of the BA.2 subvariant to infect household contacts, as well as vaccine efficacy against BA.2.

The study was conducted in Denmark during late December 2021 and January 2022. Of 8541 cases of COVID-19, about one-quarter were due to the BA.2 subvariant. The secondary attack rate of infection associated with the Omicron BA.1 and BA.2 subvariants were 29% and 39%, respectively, indicating increased transmissibility associated with BA.2.

Moreover, BA.2 was associated with a higher risk for transmission among household contacts regardless of their vaccination status; however, BA.2 was not more transmissible than BA.1 in cases in which the primary case had been fully vaccinated or had received a COVID-19 booster vaccine.

One of the most common significant consequences of any SARS-CoV-2 infection is prolonged symptoms over months after the infection. There have been multiple studies that evaluated the effect of COVID-19 vaccination and the risk for long COVID, and the current review by the UK Health Security Agency summarizes the findings from this body of research. Long COVID, also known as post acute sequalae of a SARS-CoV-2 infection and post COVID-19 syndrome, has several definitions, but most often includes having persistent symptoms of COVID-19, usually for weeks but potentially for months or years . Symptoms commonly include fatigue, shortness of breath and a persistent cough, although many other symptoms have been reported.

Study Synopsis and Perspective

Vaccination against COVID-19 reduces the risk of developing long COVID and improves long COVID symptoms among persons who were unvaccinated when infected, according to a new comprehensive review by the UK Health Security Agency.[2]In all studies, fully vaccinated is defined as 2 doses of any 2-dose vaccine or 1 dose or a single dose vaccine, and partially vaccinated is defined as a single dose of a 2-dose vaccine.

The review includes data from 15 UK and international studies, with 7 studies examining whether COVID-19 vaccination before infection protects against developing long COVID and 7 studies looking at the impact of vaccination among people who already had long COVID. One study examined both.

In 6 studies, persons who received 1 or 2 vaccine doses before SARS-CoV-2 infection were less likely to develop symptoms of long COVID after infection.

In 2 studies, fully vaccinated people were less likely than unvaccinated people to develop medium- or long-term symptoms, such as fatigue, headache, weakness in the arms and legs, persistent muscle pain, hair loss, dizziness, shortness of breath, loss of smell, or lung scarring.

In addition, 3 studies comparing long COVID symptoms before and after vaccination found that most people reported an improvement in symptoms after vaccination, either immediately or over several weeks. A few cases reported a worsening in symptoms after vaccination.

“There is also evidence that unvaccinated people with long COVID who were subsequently vaccinated had, on average, reduced long COVID symptoms, or fewer long COVID symptoms than those who remained unvaccinated,” the review said.

Scientists are not yet sure why vaccination leads to an improvement in symptoms for some people, according to The Guardian.[3] Additional research is being conducted.

“The term ‘long COVID’ covers a wide range of post-COVID conditions and so we don’t yet fully understand all the processes involved,” Deborah Dunn-Walters, chair of the British Society for Immunology’s COVID-19 Taskforce, told the Science Media Centre.[4]

“The immune system is thought to play a role in symptom development in a significant number of cases, likely as a result of an overreactive and/or slightly misdirected immune response during the acute COVID infection,” she said.

Study Highlights

  • The current update from the UK Health Security Agencyevaluated research available up to January 12, 2022, which focused on the efficacy of COVID-19 vaccination against long COVID.
  • 15 studies reported on the efficacy of vaccination against long COVID; 8 of these studies were conducted in the United Kingdom or United States.
  • 7 studies assessed the evidence of vaccination against long COVID among patients who had not been infected, and 7 studies assessed vaccine efficacy against long COVID after an initial infection; 1 study combined both of these patient cohorts.
  • The definition of long COVID was variable in different studies.
  • In a study of 16,800 participants, the odds ratio (OR) for COVID-19 symptoms ≥ 28 days’ duration among fully vaccinated vs unvaccinated participants was 0.51 (95% CI: 0.32, 0.82). The respective OR for partially vaccinated vs unvaccinated participants was 1.04 (95% CI: 0.86, 1.25).
  • Vaccination was particularly effective in the prevention of long COVID among young adults in this study.
  • In another study, the HR for long COVID of ≥ 6 months of duration was 0.87 (95% CI: 0.83, 0.92) in comparing vaccinated and unvaccinated individuals.
  • In one study focused on olfactory dysfunction, vaccination was effective in the prevention of this symptom at the outset of illness but not at 4 weeks.
  • A study that assessed individual symptoms of long COVID found that vaccination was most effective in preventing fatigue, persistent muscle pain, hair loss, dizziness, and dyspnea.
  • In contrast, a large case-control study failed to find that vaccination was protective against long COVID lasting ≥ 6 months. This study used a composite of 9 symptoms to define long COVID cases, and full vaccination was still associated with improved rates of 6 of these symptoms at 6 months after infection.
  • In a study of 6729 participants who had COVID-19 (23.7% of whom had long COVID), both doses of the COVID-19 vaccine were associated with improvement of symptoms. There was little difference in this outcome in comparing the mRNA-based and adenovirus-based vaccines.
  • In a study using online survey data among 380 participants with long COVID, 31% reported a worsening of symptoms after vaccination; 22% reported improved symptoms after vaccination, and 47% had no change in symptoms after vaccination.
Study Limitations
  • There is a risk in all these studies that factors other than vaccination status may have influenced the results (in any directions).
  • Participation in the study may been chosen by individuals who either had good or poor experiences with long COVID and vaccination and for studies that recruited from hospitals where participants may have had more severe disease or comorbidities.
  • The studies were conducted at different points in the pandemic and in different countries and notably no studies accounted for, or reported on the COVID-19 variant in their analyses.
  • The studies where vaccination occurred before infection only include people who were infected with COVID-19, meaning no effect of vaccination on preventing COVID-19 infection in the first place was included in the results. As a result, the total effect of vaccination on prevention of long COVID will have been underestimated.
  • All studies were observational so the results may be from differences other than vaccination, and there was large heterogeneity between various studies in the definition of long COVID.

Clinical Implications

  • A preprint study by Lyngse and colleagues found that the Omicron BA.2 subvariant spread more efficiently in households compared with the BA.1 subvariant, regardless of the vaccination status of household contacts; however, the increased transmission of BA.2 was obviated when the index case of COVID-19 was vaccinated.
  • The current review by the UK Health Security Agency suggests that vaccination before contracting COVID-19 can prevent long COVID, even for symptoms persisting for 6 months. There is mixed evidence as to whether vaccination against COVID-19 can improve long COVID among persons with COVID-19, with a preponderance of evidence suggesting vaccination might help these patients.
  • Implications for the healthcare team: The healthcare team should use the prevention of long COVID as a tool to inform patients on the benefits of the COVID-19 vaccine.


Earn Credit

  • Print