Characterisation of COVID-19 disease throughout the three waves: an insight on 300 patients evaluated at the Emergency Department

The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) was initially detected in China in December 2019. From there, it spread across all six continents and was declared a pandemic by the World Health Organisation (WHO) in March 11th 2020. As of June 1st, 2021 it has caused 170.724.858 cases and 3.550.179 deaths worldwide. The illness caused by SARS-CoV-2 was named Coronavirus Disease 2019 (COVID-19) and its presentation ranges from asymptomatic to severe. Common symptoms include fever, fatigue, dry cough and anosmia or ageusia; however, pneumonia, respiratory failure and even acute respiratory distress syndrome (ARDS), multiorgan failure (MOF) and death can occur. In addition, extrapulmonary manifestations are common and because of this the concept of COVID-19 as a systemic disease is gaining attention and approval by the scientific community. During the past year, scientific knowledge on COVID-19 profoundly evolved. On one hand, better understanding of the best therapeutic approach determined an improvement in the prognosis of patients. At the same time, enhanced monitoring activity by family doctors and USCA (Unità Speciali di Continuità Assistenziale) allowed to treat patients with mild disease at home, so that only at later and more severe stages would they require hospital admission. Further progress was made on the development and distribution of vaccines, whose beneficial effects include reduce morbidity and mortality rate. Lastly, the emergence of concerning viral variants posed a considerable risk on the evolution of the disease and the progress made in the previous months. In our study, we retrospectively evaluated the clinical presentation, biochemical profile, echographic pattern and prognosis of patients who presented at the Emergency Department of IRCCS Policlinico San Matteo during the three COVID-19 waves. Specifically, data of 300 patients, equally divided for each epidemiological wave, were analysed, with periods running from February 2020 to April 2020, from October 2020 to December 2020 and from February 2021 to April 2021. Results were compared to determine the behaviour and evolution of COVID-19 throughout the past year, from the point of view of the reality of Emergency physicians.