Fatigue is the most common persistent symptom of COVID-19 in different variants of the virus

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A research group led by the Rey Juan Carlos University (URJC) and in which the University of Valencia (UV) and the Complutense University of Madrid (UCM) participate has for the first time compared the symptoms at the beginning and six months after three groups of patients infected with different variants (Wuhan, alpha and delta) of SARS-CoV-2 who required hospitalisation. One of the main conclusions of the research, published in the journal Pathogens, is that fatigue is a symptom that affects patients in a similar proportion regardless of the variant of the virus.

"By remaining constant through the variants, it may be one of the key clinical criteria for defining this disease", says César Fernández de las Peñas, professor at the Department of Physiotherapy, Occupational Therapy, Rehabilitation and Physical Medicine at the URJC. However, the large number of symptoms associated with SARS-CoV-2 "makes it difficult to establish a single diagnostic criterion", he adds.

According to the study, patients infected with the Wuhan variant had on average more symptoms in the acute phase of the disease than the rest of the variants, among which fever, dyspnea - difficulty breathing - and gastrointestinal symptoms were the most common, while that with the delta variant there was more headache and anosmia - loss of smell - "These differences have been observed in the clinic throughout the different waves, but we have been the first to systematically compare them in a scientific study", says Fernández de las Peñas.

"Our work has consisted of analysing the data of the different variants to see if there are significantly different differences between the symptoms and sequelae of the different variants of the virus", highlights José David Martín, Professor of Electronic Engineering at the University of Valencia, and signatory of the article together with another researcher from the same department, Óscar Pellicer. This research is part of a broader collaboration, fundamentally with the Rey Juan Carlos University, in which UV experts analyse data sets of patients affected by COVID in the Community of Madrid, to draw conclusions about the varieties, dependence of symptoms in the short and long term with gender or with the permanence of more specific effects.

Telephone follow-up six months later

To carry out the study, the researchers reviewed the data of the 200 patients during their hospitalisation. Six months after the acute condition, telephone interviews were conducted to learn about the situation and symptoms of these people after hospitalisation. Fatigue had a similar persistence in the three groups of patients, although there were multiple symptoms with all variants of the virus.

Those infected with the Wuhan variant had a higher number of persistent symptoms (3 versus 2 for the rest of the variants), and dyspnea was the most frequent one. Patients with delta reported more alopecia.

"It seems that the incidence of persistent COVID may be lower as time goes by and in the presence of new variants such as omicron, probably conditioned by vaccination, but it is still a serious problem given the large number of infections that occur", says Juan Torres Macho, researcher at the UCM Department of Medicine and co-author of the work.

In addition to the UV, the URJC and the UCM, the San Carlos Clinical Hospital, the Infanta Leonor-Virgen de la Torre University Hospital, and the University of Aalborg (Denmark) have participated in the research.

Article: Fernández-de-las-Peñas, C.; Cancela-Cilleruelo, I.; Rodríguez-Jiménez, J.; Gómez-Mayordomo, V.; Pellicer-Valero, O.J.; Martín-Guerrero, J.D.; Hernández-Barrera, V.; Arendt-Nielsen, L.; Torres-Macho, J. ’Associated-Onset Symptoms and Post-COVID-19 Symptoms in Hospitalized COVID-19 Survivors Infected with Wuhan, Alpha or Delta SARS-CoV-2 Variant’. Pathogens 2022, 11, 725. DOI: 10.3390/pathogens11070725. Link: https://www.mdpi.com/2076-081­7/11/7/725

Annex photo caption : José David Martín and Óscar Pellicer, researchers at Department of Electronic Engineering of the University of Valencia.