Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) promotes challenging immune and inflammatory phenomena. Though various therapeutic possibilities have been tested against coronavirus disease 2019 (COVID-19), the most adequate treatment has not yet been established. Among candidate adjunct treatment options, propolis, produced by honey bees from bioactive plant exudates, has shown potential against viral targets and has demonstrated immunoregulatory properties.

To evaluate the efficacy and safety of oral propolis as an adjunct treatment for SARS-CoV-2 infection, we designed a randomized, double-blind, placebo-controlled trial (Bee-Covid2) (The Use of Brazilian Green Propolis Extract (EPP-AF®) in Patients Affected by COVID-19).

Inclusion Criteria:

• Older than 18 years;
• Diagnosis of coronavirus infection confirmed by polymerase chain reaction - reverse transcriptase testing;
• Symptoms started within 14 days of the randomization date

Exclusion Criteria:

• Pregnant or lactating women;
• Known hypersensitivity to propolis;
• Propolis use less than 30 days from the randomization date;
• Active cancer;
• Human immunodeficiency virus carriers;
• Patients undergoing transplantation of solid organs or bone marrow or who were using immunosuppressive medications;
• Bacterial infection at randomization, sepsis or septic shock related to bacterial infection at randomization;
• Impossibility of using the medication orally or by nasoenteral tube;
• Known hepatic failure or advanced heart failure (New York Heart Association [NYHA] class III or IV).
• End Stage Renal Disease (ESRD).

The data presented in this study are available on request from the corresponding author.

The capsules will be coated, in opaque and equal packaging, so that the researchers involved in the care of patients could not distinguish between propolis and placebo. Neither the participants, nor the principal investigator, nor the health professionals involved in the care will know which group the patients will be allocated.