The definition of ‘long-COVID syndrome’ (LCS) is still debated and describes the persistence of symptoms after viral clearance in hospitalized or non-hospitalized patients affected by coronavirus disease 2019 (COVID-19).

In this study, we examined the prevalence and the risk factors of LCS in a cohort of patients with previous COVID-19 and followed for at least 6 months of follow-up.

We conducted a prospective study including all hospitalized patients affected by COVID-19 at our center of Infectious Diseases (Vercelli, Italy) admitted between 10 March 2020 and 15 January 2021 for at least 6 months after discharge. Two follow-up visits were performed: after 1 and 6 months after hospital discharge. Clinical, laboratory and radiological data were recorded at each visit.

A total of 449 patients were included in the analysis. The LCS was diagnosed in 322 subjects at Visit 1 (71.7%) and in 206 at Visit 2 (45.9); according to the post-COVID-19 functional status scale we observed 147 patients with values 2–3 and 175 with values >3 at Visit 1; at Visit 2, 133 subjects had the score between 2–3 and 73 > 3. In multivariate analysis, intensive care unit (ICU) admission (OR = 2.551; 95% CI = 1.998–6.819; P = 0.019), time of hospitalization (OR = 2.255; 95% CI = 1.018–6.992; P = 0.016) and treatment with remdesivir (OR = 0.641; 95% CI = 0.413–0.782; P < 0.001) were independent predictors of LCS.

Treatment with remdesivir leads to a 35.9% reduction in LCS rate in follow-up. Severity of illness, need of ICU admission and length of hospital stay were factor associated with the persistence of PCS at 6 months of follow-up.