Abstract
Effective vaccination against coronavirus mitigates the risk of hospitalisation and mortality; however, it is unclear whether vaccination status influences long COVID symptoms in patients who require hospitalisation. The available evidence is limited to outpatients with mild disease. Here, we evaluated 412 patients (age: 60 ± 16 years, 65% males) consecutively admitted to two Hospitals in Brazil due to confirmed coronavirus disease 2019 (COVID-19). Compared with patients with complete vaccination (n = 185) before infection or hospitalisation, those with no or incomplete vaccination (n = 227) were younger and had a lower frequency of several comorbidities. Data during hospitalisation revealed that the no or incomplete vaccination group required more admissions to the intensive care unit (ICU), used more corticosteroids, and had higher rates of pulmonary embolism or deep venous thrombosis than the complete vaccination group. Ninety days after hospital discharge, patients with no or incomplete vaccination presented a higher frequency of symptoms (≥ 1) than patients with complete vaccination (40 vs. 27%; p = 0.013). After adjusting for confounders, no or incomplete vaccination (odds ratio [OR] 1.819; 95% confidence interval [CI] 1.175-2.815), female sex (OR 2.435; 95% CI 1.575-3.764) and ICU admission during hospitalisation (OR 1.697; 95% CI 1.062-2.712) were independently associated with ≥ 1 symptom 90 days after hospital discharge. In conclusion, even in patients with severe COVID-19, vaccination mitigates the probability of long COVID symptoms.