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. 2022 Dec 21;10(6):e0253722.
doi: 10.1128/spectrum.02537-22. Epub 2022 Nov 9.

Self-Reported Long COVID and Its Association with the Presence of SARS-CoV-2 Antibodies in a Danish Cohort up to 12 Months after Infection

Kamille Fogh  1   2   3 , Tine Graakjær Larsen  4 , Cecilie B Hansen  5   3 , Rasmus B Hasselbalch  1   2   3 , Alexandra R R Eriksen  1   2   3 , Henning Bundgaard  6   3 , Ruth Frikke-Schmidt  7   3 , Linda M Hilsted  3 , Lars Østergaard  8   9 , Isik S Johansen  10   11 , Ida Hageman  12 , Peter Garred  5   3 , Kasper Iversen  1   2   3
Affiliations

Self-Reported Long COVID and Its Association with the Presence of SARS-CoV-2 Antibodies in a Danish Cohort up to 12 Months after Infection

Kamille Fogh et al. Microbiol Spectr. .

Abstract

The majority of long coronavirus disease (COVID) symptoms are not specific to COVID-19 and could be explained by other conditions. The present study aimed to explore whether Danish individuals with a perception that they suffer from long COVID have antibodies against the nucleocapsid antigen, as a proxy for detecting previous infection. The study was conducted in February and March 2021, right after the second surge of the COVID-19 pandemic in Denmark. All members of the social media group on Facebook "Covidramte med senfølger" ("long COVID sufferers'') above the age of 17 years and living in Denmark were invited to participate in a short electronic questionnaire about long COVID risk factors and symptoms. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid (N) protein was detected in blood samples as a proxy for natural SARS-CoV-2 infection. The final study population comprised 341 participants (90.6% females) who completed blood sampling and answered the questionnaire. A total of 232 (68%) were seropositive (median age, 49.5 years; interquartile range [IQR], 41 to 55 years; 90.1% females). There was no significant difference between sexes and serostatus. Seronegative and seropositive individuals had a similar burden of symptoms that could be attributed to long COVID. Time since perceived COVID-19 was significantly longer in the group of seronegative individuals than the seropositive ones (P < 0.001). This study suggests that long-COVID sufferers are mostly women and showed that a third of the participants did not have detectable anti-N-protein antibodies. It emphasizes the importance of early confirmation of COVID-19, as this study indicates an overlap between long-COVID symptoms and symptoms that are possibly of another origin. IMPORTANCE This cohort study included questionnaire data as well as anti-nucleocapsid antibody analysis, allowing us to determine whether participants were seropositive due to vaccination or natural infection. The study emphasizes the importance of early confirmation of COVID-19, as antibodies recede with time, and it indicates an overlap between long COVID symptoms and symptoms possibly of another origin.

Keywords: N protein; PASC; SARS-CoV-2; SARS-CoV-2 antibodies; antibodies; long COVID; nucleocapsid antigen; post-COVID syndrome; post-acute-phase COVID-19; prolonged COVID.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

FIG 1
FIG 1
Mean change in symptoms.
FIG 2
FIG 2
Serostatus and time since COVID-19.
FIG 3
FIG 3
Feelings in the previous 4 weeks.
FIG 4
FIG 4
Consort flow diagram.
See this image and copyright information in PMC

References

    1. National Institute for Health and Care Excellence. 2020. COVID-19 rapid guideline: managing the long-term effects of COVID-19. https://www.nice.org.uk/guidance. - PubMed
    1. Lamontagne SJ, Winters MF, Pizzagalli DA, Olmstead MC. 2021. Post-acute sequelae of COVID-19: evidence of mood & cognitive impairment. Brain Behav Immun Health 17:100347. doi: 10.1016/j.bbih.2021.100347. - DOI - PMC - PubMed
    1. Yelin D, Wirtheim E, Vetter P, Kalil AC, Bruchfeld J, Runold M, Guaraldi G, Mussini C, Gudiol C, Pujol M, Bandera A, Scudeller L, Paul M, Kaiser L, Leibovici L. 2020. Long-term consequences of COVID-19: research needs. Lancet Infect Dis 20:1115–1117. doi: 10.1016/S1473-3099(20)30701-5. - DOI - PMC - PubMed
    1. World Health Organization. 2021. In the wake of the pandemic: preparing for long COVID. https://www.euro.who.int/en/health-topics/health-emergencies/coronavirus.... - PubMed
    1. Stengel A, Malek N, Zipfel S, Goepel S. 2021. Long haulers—what is the evidence for post-COVID fatigue? Front Psychiatry 12:677934. doi: 10.3389/fpsyt.2021.677934. - DOI - PMC - PubMed

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