COVID-19 can present as a life-threatening disease characterised by respiratory failure
and high circulating levels of inflammatory cytokines. Beta-glucans comprise a
heterogeneous group of natural polysaccharides consisting of D-glucose monomers linked by
a beta-glycosidic bond. They represent key structural elements of the cell wall and may
serve as energy storage in bacteria, fungi including yeast, algae, and plants. In this
triple-masked randomised trial, hospitalised patients requiring treatment with
supplemental oxygen because of a laboratory-confirmed infection by SARS-CoV-2 will
receive supplementation with 1-3 beta-glucans or placebo as part of their standard
treatment. The primary endpoint of this trial is the intensity of clinical symptoms as
detected by the Wisconsin Upper Respiratory Symptom Survey (WURSS).

Patients requiring mechanical ventilation at baseline will be excluded, as will those
with cognitive impairment that precludes the use of clinical assessment scales, patients
in which an order to limit therapeutic efforts has been issued, pregnant or breastfeeding
women and those who decline to participate in this study. Secondary outcomes will include
clinical deterioration requiring admission to an intensive care unit, requirement of
high-flow nasal cannula or invasive mechanical ventilation and overall survival. Patients
will be followed-up until hospital discharge or up to fifteen days after randomisation.
Statistical analyses will be undertaken by a statistician unaware of treatment allocation
under the intention-to-treat principle.