COVID-19 Evidence Alerts
from McMaster PLUSTM

Current best evidence for clinical care (more info)

Primary Prevention Notarte KI, Catahay JA, Velasco JV, et al. Impact of COVID-19 vaccination on the risk of developing long-COVID and on existing long-COVID symptoms: A systematic review. EClinicalMedicine. 2022 Aug 27;53:101624. doi: 10.1016/j.eclinm.2022.101624. eCollection 2022 Nov.
PICO Terms
adult (P) Breakthrough infection; post-vaccination COVID-19 (P) Comirnaty; Pfizer vaccine; BNT162b2; BioNTech/Fosun Pharma; mRNA (I/C) fully vaccinated (I/C) health care workers (HCW) (P) influenza vaccine (I/C) Johnson & Johnson vaccine; Janssen Pharmaceutical Companies; Ad26.COV2.S; non-replicating viral vector (I/C) Long COVID; PASC (post-acute sequelae SARS-CoV-2 infection); post-COVID-19 condition (O) partially vaccinated (I/C) previously infected (P) Spikevax; Moderna vaccine; mRNA-1273 SARS-CoV-2; ModernaTX; mRNA (I/C) unvaccinated (I/C) vaccine effectiveness (O) Vaxzevria; AstraZeneca vaccine; ChAd0x1 nCOV-19; non-replicating viral vector; adenovirus; University of Oxford/AstraZeneca; AZD1222 (I/C)

Background: Although COVID-19 vaccination decreases the risk of severe illness, it is unclear whether vaccine administration may impact the prevalence of long-COVID. The aim of this systematic review is to investigate the association between COVID-19 vaccination and long-COVID symptomatology.

Methods: MEDLINE, CINAHL, PubMed, EMBASE, and Web of Science databases, as well as medRxiv and bioRxiv preprint servers were searched up to June 20, 2022. Peer-reviewed studies or preprints monitoring multiple symptoms appearing after acute SARS-CoV-2 infection either before or after COVID-19 vaccination collected by personal, telephone or electronic interviews were included. The methodological quality of the studies was assessed using the Newcastle-Ottawa Scale.

Findings: From 2584 studies identified, 11 peer-reviewed studies and six preprints were included. The methodological quality of 82% (n=14/17) studies was high. Six studies (n=17,256,654 individuals) investigated the impact of vaccines before acute SARS-CoV-2 infection (vaccine-infection-long-COVID design). Overall, vaccination was associated with reduced risks or odds of long-COVID, with preliminary evidence suggesting that two doses are more effective than one dose. Eleven studies (n=36,736 COVID-19 survivors) investigated changes in long-COVID symptoms after vaccination (infection-long-COVID-vaccine design). Seven articles showed an improvement in long-COVID symptoms at least one dose post-vaccination, while four studies reported no change or worsening in long-COVID symptoms after vaccination.

Interpretation: Low level of evidence (grade III, case-controls, cohort studies) suggests that vaccination before SARS-CoV-2 infection could reduce the risk of subsequent long-COVID. The impact of vaccination in people with existing long-COVID symptoms is still controversial, with some data showing changes in symptoms and others did not. These assumptions are limited to those vaccines used in the studies.

Funding: The LONG-COVID-EXP-CM study supported by a grant of Comunidad de Madrid.

Discipline / Specialty Area Score
Family Medicine (FM)/General Practice (GP)
General Internal Medicine-Primary Care(US)
Public Health
Internal Medicine
Comments from MORE raters

Internal Medicine rater

This is definitely an important question as it may influence the uptake of COVID-19 vaccination and the public health information that practitioners like myself provide to our patients. However, this article also clearly points out that much more research is still required to begin to answer the question if vaccines are able to prevent long-Covid-19 symptoms.

Internal Medicine rater

As an Internal Medicine physician, I find this article/review highly relevant, especially in the province where I am currently located in the Philippines. Vaccination information is not well defined nor well disseminated here, particularly its uses and benefits. Also, people/patients are not very compliant with getting Covid vaccinations were it not for the government limiting the benefits they receive if they are not vaccinated. In summary, with the review stating the benefits of the Covid vaccine, it gives us better understanding and a tool that can help physicians better educate our patients and, hopefully, convince them to get vaccinated.

Internal Medicine rater

As a generalist, the benefit of this article to me is that it provides evidence when I am asked to give an opinion or advice to my colleagues.