Long COVID-associated symptoms prevalent in both SARS-CoV-2 positive and negative individuals: A prospective follow-up study

Anu Kantele; Juuso Paajanen; Jukka-Pekka Pietilä; Olli Vapalahti; Sari H Pakkanen; Tinja Lääveri

doi:10.1016/j.nmni.2023.101209

Long COVID-associated symptoms prevalent in both SARS-CoV-2 positive and negative individuals: A prospective follow-up study

New Microbes New Infect. 2023 Dec 7:56:101209. doi: 10.1016/j.nmni.2023.101209. eCollection 2024 Jan.

Authors

Anu Kantele^{1

2

3}, Juuso Paajanen⁴, Jukka-Pekka Pietilä^{1

3}, Olli Vapalahti^{5

6}, Sari H Pakkanen^{1

3}, Tinja Lääveri^{1

3

2

6

7}

Affiliations

¹ Meilahti Infectious Diseases and Vaccine Research Center, MeiVac, Biomedicum 1, Haartmaninkatu 8, Helsinki University Hospital and University of Helsinki, 00290, Helsinki, Finland.
² Department of Infectious Diseases, Helsinki University Hospital, Helsinki, Finland.
³ Human Microbiome Research Program, Faculty of Medicine, Haartmaninkatu 4, 00014, University of Helsinki, Helsinki, Finland.
⁴ Department of Pulmonary Medicine, Heart and Lung Center, Helsinki University Hospital and University of Helsinki, Finland.
⁵ Viral Zoonoses Research Unit, Departments of Virology and Veterinary Biosciences, Faculties of Medicine and Veterinary Medicine, 00014, University of Helsinki, Helsinki, Finland.
⁶ Helsinki University Hospital Diagnostic Center, HUSLAB, Clinical Microbiology, Topeliuksenkatu 32, 00290, Helsinki, Finland.
⁷ Department of Computer Science, Aalto University, PO Box 15400, FI-00076, AALTO, Finland.

Abstract

Background: Research into persistent symptoms among SARS-CoV-2-positive i.e. CoV(+) patients mostly focuses on hospitalized individuals. Our prospective follow-up study compares long COVID-associated symptoms among laboratory-confirmed CoV(+) and SARS-CoV-2 negative [CoV(-)] individuals.

Methods: SARS-CoV-2 RT-PCR-tested volunteers were recruited into four cohorts: 1) CoV(+) outpatients, 2) CoV(-) outpatients, 3) CoV(+) intensive care unit (ICU) inpatients, and 4) CoV(+) non-ICU inpatients. Neutralizing antibodies were assessed and questionnaires filled in at enrolment and days 90-120, 121-180, 181-270, 271-365, and 365-533.

Results: Of the 1326 participants, 1191 were CoV(+): 46 ICU, 123 non-ICU, and 1022 outpatients; 135 were CoV(-) outpatient controls. Both CoV(+) outpatients and CoV(-) controls showed high overall symptom rates at all time points. More prevalent among CoV(+) than CoV(-) outpatients were only impaired olfaction and taste; many others proved more frequent for CoV(-) participants. At ≥181 days, fatigue, dyspnoea, various neuropsychological symptoms and several others were recorded more often for CoV(+) inpatients than outpatients.

Conclusions: Long COVID-associated symptoms were more frequent among hospitalized than non-hospitalized CoV(+) participants. As for outpatients, only impaired olfaction and taste showed higher rates in the CoV(+) group; some symptoms proved even more common among those CoV(-). Besides suggesting low long COVID prevalences for outpatients, our results highlight the weight of negative controls.

Keywords: Follow-up study; Long covid; SARS-CoV-2.