Changing patterns and clinical outcomes of hospitalized patients with COVID-19 severe pneumonia treated with remdesivir according to vaccination status: results from a real-world retrospective study

Since the beginning of Coronavirus Disease 2019 (COVID-19) pandemic, many drugs have been purposed for the treatment of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). Remdesivir emerged as an encouraging antiviral drug for patients with documented severe COVID-19-related pneumonia. Although several studies about remdesivir effectiveness exist, no study investigated the effect of the combination of remdesivir with the vaccination status. The aim of this study was to assess whether the administration of remdesivir could show some differences in terms of clinical outcomes in patients vaccinated against SARS-CoV-2 versus those who were not. The primary outcome was the in-hospital mortality. The secondary outcomes were 30-days mortality, the need for ICU admission and for oxygen supplementation. This is a retrospective cohort study including all consecutive adult patients hospitalized for severe COVID-19 at the Padua University Hospital (Italy), between September 1st, 2020, and January 31st, 2022, and who received a 5-days course of remdesivir. A total of 708 patients were included, 467 (66%) were male, and the median age was 67 (IQR: 56-79) years. To better estimate the outcomes of interest, a propensity score weighted approach was implemented for vaccination status. A total of 605/708 patients (85.4%) did not complete the vaccination schedule. In-hospital mortality rate was 5.1% (n = 36), with no statistically significant difference between the unvaccinated (n=29, 4.8%) and vaccinated (n=7, 6.8%; p=0.4) patients. After propensity score matching, mortality between the two groups remained similar. However, both the need for ICU and oxygen supplementation were significantly lower in the vaccinated group. Our finding suggests that a complete vaccination course could have an impact in reducing the need for transfer in ICU and for high-flow therapy in moderate-to-severe COVID-19 patients treated with remdesivir.