This study will be carried out by more than 30 liberal Tunisian doctors, who will submit according to the inclusion / exclusion criteria of people who will receive (free of charge) a capsule of the Nig5 product sublingually, each day. Against a control group which will be followed with the same protocol as the first but which will not receive the product. Randomization (even days: nigella group, odd days: control group)

This study will focus on the evaluation of the natural product Nigella Sativa in the fractalized form. "Lactose Nigelle 5" from the Tunisian company Fractal Tun, in terms of possible contribution to the prevention of influenza-like illnesses, in particular COVID-19

It will be carried out by more than 30 liberal Tunisian doctors, who will submit according to the inclusion / exclusion criteria of people who will receive (free of charge) a capsule of the Nig5 product sublingually, each day. Against a control group which will be followed with the same protocol as the first but which will not receive the product. Randomization (even days: nigella group, odd days: control group)

The monitoring and evaluation will last for 3 weeks with taking the product Nig5, followed by a week without taking the product. That is 4 weeks in all.

More than 30 physicians volunteered to participate in this study without remuneration and without consultation fees for the candidates.

This study will be supervised by Professor Riadh Boukef, head of emergency services at Sahloul University Hospital, who will collect all the data afterwards in order to submit them to the statistical tools in force.

Professor Boukef will be responsible for preparing the abstract and publishing it on his behalf in the scientific journals of his choice, naming the doctors who participated as well as the product in question and the company that markets it in Tunisia.

27 free practice doctors participate in patient recruitment: AMICHE Sondèss BAHA Mohamed BEN AMARA Mohamed Khalil BEN ARBIA Karima BEN AYAD Afef BEN AYED KTARI Fouzia BENTALEB Mourad BESBES Mohamed CHTOUROU Iteb DHOUIB Manel DJAIT Mohamed DJEMAL Najla ELFIDHA Mongi FOURATI Imen FRIH Sabria FRIKHA Fahmi GHARBI Nadia KAMMOUN Naziha KETATA Mourad MHIRI Ikram NJAH Jamil OUARGHI Sameh REGAIEG Mourad SAKKA Samar TRABELSI Hinda ZOUARI Imen ZOUARI Nassira

Inclusion Criteria:

• patients with an age> 40 years

Exclusion Criteria:

• Being positive for COVID or having contracted it previously
• Positive for COVID between D1 and D5 of the study, meaning that there was infection before inclusion.
• Immunocompromised (HIV, other ...)
• Under chemotherapy
• On immunosuppressants
• Pregnant women

Data Statistical analysis

The data will be available after publication

all Criteria will be shared in the accepted article