International journal of infectious diseases : IJID : official publication of the International Society for Infectious DiseasesMay 28, 2026

Long COVID symptoms before and up to 3 years after COVID-19 infection in Norway, comparing different pandemic periods and virus variants

Long Covid Weekly Brief ↗PubMed ↗DOI ↗

Updated Jun 27, 2026

Abstract

Essence

Long COVID symptoms persisted for some Norwegians up to 35 months after infection, but symptom prevalence declined later in the pandemic and after Omicron-period infections.

Evidence

Norwegian prospective cohort study surveyed 115737 adults aged 18-96 years with 1-6 questionnaires 3-35 months after positive and/or negative SARS-CoV-2 tests from 2020-2023.

Caveat

The study relies on questionnaire-reported symptoms after testing, and variant-period comparisons remain observational rather than randomized.

Simplified

OBJECTIVES: Examine long COVID symptoms, prevalence of symptoms over the pandemic, and compare symptoms due to the Omicron variants with symptoms due to earlier variants of the SARS-CoV-2 virus.

METHODS: In the present Norwegian prospective cohort study 115737 persons, 18-96 years, completed 1-6 questionnaires 3-35 months after a positive and/or negative SARS-CoV-2 test between 2020-2023.

RESULTS: The following symptoms were reported more frequently 3-35 months after than before positive SARS-CoV-2 test (n=37400): worsening of health, (OR 1.79 [CI 1.71-1.86]), memory problems (2.21 [2.06-2.37]), concentration problems (1.98 [1.87-2.09]), dyspnea (1.95 [1.84-2.07]), fatigue (1.46 [1.41-1.52]) and smell/taste changes (3.12 [2.84-3.42]). The prevalence of symptoms was lower at the end of 2022 than in 2020. A positive SARS-CoV-2 test during the Omicron-dominated period was associated with lower prevalence of symptoms than a positive test during the period dominated by earlier variants.

CONCLUSIONS: Several symptoms lingered up to 35 months post-SARS-CoV-2 infection. The prevalence of symptoms decreased over the course of the pandemic and were reported less often in those infected with later SARS-CoV-2 variants than earlier variants. The indications of long-term persisting symptoms after COVID-19 and the consequences of new variants should be further monitored.