Long COVID symptoms persisted for up to two years in more than half of the individuals who experienced the condition, according to new [research](https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-025-03974-7) published in _BMC Medicine_.
Researchers from ISGlobal and the Germans Trias i Pujol Research Institute followed 2,764 adults in Catalonia who were infected with SARS-CoV-2 between 2020 and 2023. They found that 23% of infected individuals developed long COVID, defined as symptoms persisting for at least three months. Significantly, 56% of these patients continued to experience symptoms two years later, highlighting the potential long-term impact of the condition.
“Our results show that a significant percentage of the population has long COVID, which in some cases affects their quality of life,” says Judith Garcia-Aymerich, MD, PhD, Barcelona Institute of Global Health (ISGlobal) and author of the study.
Researchers identified three distinct clinical subtypes of [long COVID](https://www.mcknights.com/news/covid-19-linked-to-lower-physical-function-in-older-women-report-shows/): one primarily affecting the neurological and musculoskeletal systems, another targeting the respiratory system, and a severe form involving multiple organs. The severe multi-organ subtype showed the highest likelihood of symptom persistence.
Several risk factors emerged from the analysis. Women, those who experienced severe COVID-19 infections, and individuals with pre-existing chronic conditions (particularly asthma, mental health disorders and digestive diseases) faced higher risks. Obesity and elevated prevaccination antibody levels also increased susceptibility.
Conversely, the study identified protective factors that reduced long COVID risk. These included vaccination before infection, regular physical activity, adequate sleep (six to eight hours), and infection after the omicron variant became dominant.
By using a population-based cohort rather than clinical data, the research provides broader insights into long-COVID’s impact across a general population.
Manolis Kogevinas, MD, PhD, lead author of the study, emphasized that this approach “allowed us to better estimate the magnitude of long-COVID and identify risk and protective factors.”