Background : Coronavirus disease known as COVID-19 is caused by the SARS-CoV-2. Transmission of SARS CoV-2 is spreading from human to human through direct or indirect droplets, this disease then spreads very quickly to various countries until it becomes a pandemic. Rhea® Health Tone is an essential oil made from Gardenia jasminoides, Commiphora myrrha, Boswellia serrata, Daucus carota, Foeniculum vulgarae, and Olea Europeae that have antimicrobial and anti-inflammatory effects. Rhea® Health Tone also has been registed on BPOM. Even so, the efficacy of Rhea® Health Tone still needs to be studied further.

This research aimed to assess the efficacy and safety of healthtone as prophylaxis for COVID-19 in human resources at persahabatan central general hospital.The intervention group received Rhea® Health Tone 2 times supplementation 1 ml a day; meanwhile, the control group received placebo 2 times supplementation 1 ml a day.

This study is a double-blind randomized clinical trial on the human resources population at Persahabatan Central General Hospital, Jakarta.

Subjects who have agreed to be included in the study will undergo an initial examination and a serological examination of IgG SARS-CoV-2 to ensure that there is no adequate immunity against COVID-19 before the study begins. After confirmed that all subjects are not included in the exclusion criteria and not infected with COVID-19, randomization will be conducted to determine who gets the Rhea®️ Health Tone or a placebo.

Evaluation will be carried out until the 84th day of giving the intervention. The subject will be monitored everyday by the research team to ask whether there are symptoms experienced by the subject, both symptoms related to COVID-19 and symptoms related to side effects drugs and adverse events.

The statistical test used in this study was the Chi-square test or Fisher's exact test.

Inclusion Criteria:

• Age 18-65 years old
• Human resources in persahabatan central general hospital while being a research subject
• Wear PPE according to their respective work standards.
• Not previously infected with COVID-19, or have been infected with COVID-19 19 previously with non-reactive IgG serological results.
• Have not received a COVID-19 vaccine or have received 2nd dose of vaccine COVID-19 but manifest non-reactive IgG serological results
• Subject voluntarily gave written consent to participate in this research.

Exclusion Criteria:

• Patients with severe comorbid factors such as: uncontrolled congestive heart disease, renal insufficiency, coronary heart disease, chronic liver disease, diabetes mellitus with complications, uncontrolled hypertension or crisis hypertension, immunocompromised, CNS disorders (such as stroke, epilepsy, Alzheimer's, meningitis) , cancer, HIV, AIDS.
• Subjects who are pregnant or breastfeeding.
• Subjects who cannot be included in the study according to consideration of the researcher.
• Subjects who are in the process of taking other drug clinical trials.
• Subjects with a history of allergy to the components of the test drug.